@article {lee_anomalous_2025,
	title = {Anomalous Sediment Consolidation and Alteration From Buried Incoming Plate Seamounts Along the Cascadia Margin},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {26},
	number = {2},
	year = {2025},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024GC011949},
	pages = {e2024GC011949},
	abstract = {Abstract Oceanic plate seamounts are believed to play an important role in megathrust rupture at subduction zones, although consistent relationships between subducting seamounts and plate interface seismicity patterns are not found. While most studies focus on impacts linked to their topography, seamounts are also sites of heterogeneity in incoming plate sediments that may contribute to megathrust properties. Here, we characterize incoming plate sediments along the Cascadia subduction zone using new high-resolution seismic images and compressional wave (Vp) models from the CASIE21 multi-channel-seismic experiment. Nine fully-to-partially buried seamounts are identified seaward of the deformation front within a region of thick Plio-Pleistocene sediment where the Juan de Fuca plate is bending into the subduction zone. Anomalously high Vp sediment blankets two seamounts offshore Washington-Central Oregon, with wavespeeds reaching 36\% and 20\% higher than adjacent sediment. Fluid seepage and temperatures warm enough for smectite diagenesis extending to shallow depths are inferred from heat flow studies and we attribute Vp anomalies to sediment cementation linked primarily to smectite dehydration. Signatures of fluid seepage above seamounts are also identified offshore Vancouver Island, but anomalously low Vp sediment below distinct reverse polarity reflections are found, indicating trapped fluids, and cooler basement temperatures are inferred. Landward of one seamount, a zone of enhanced sediment compaction is found, consistent with the predicted stress modulating effects of seamount subduction. These new findings of variations in sediment diagenesis and strength around seamounts prior to subduction may contribute to the diverse megathrust frictional properties and seismicity patterns evident at subducting seamounts.},
	doi = {https://doi.org/10.1029/2024GC011949},
	author = {Lee, Michelle K. and Carbotte, Suzanne M. and Han, Shuoshuo and Shuck, Brandon and Gurun, Pinar and Boston, Brian and Nedimovic, Mladen and Tobin, Harold and Norvell, Ben and Spinelli, Glenn}
}
@article {wamba_data-space_2025,
	title = {Data-space cross-validation of mantle structure in global tomographic models underneath the Pacific Ocean},
	journal = {Geophysical Journal International},
	volume = {241},
	number = {1},
	year = {2025},
	note = {_eprint: https://academic.oup.com/gji/article-pdf/241/1/241/61706719/ggaf044.pdf},
	month = {jan},
	pages = {241{\textendash}259},
	abstract = {Seismic tomography is a principal method for studying mantle structure, but imaging of Earth{\textquoteright}s wave speed anomalies is conditioned by seismic wave sampling. Global models use misfit criteria that may strive for balance between portions of the data set but can leave important regional domains underserved. We evaluate two full-waveform global tomography wave speed models, GLAD-M25 (Global adjoint tomography model) and SEMUCB-WM1 (whole-mantle tomography model derived from fully numerical spectral element method forward modelling), in the mantle below the Pacific Ocean. The region of the South Pacific Superswell contains multiple hotspots which may be fed by plumes anchored in the Large Low Shear-Velocity Province at the base of the mantle. The uneven distribution of seismic receivers worldwide leaves several candidate plumes beneath various hotspots poorly resolved. We assess the regional quality of GLAD-M25 relative to its global performance using a partition of the seismic waveform data used in its construction. We evaluate synthetic waveforms computed using the spectral-element method to determine how well they fit the data according to a variety of criteria measured across multiple seismic phases and frequency bands. The distributions of traveltime anomalies that remain in GLAD-M25 are wider for trans-Pacific paths than globally, suggesting comparatively insufficiently resolved seismic velocity structure in the region of interest. Hence, Pacific-centred regional inversions, based on (augmented) subsets of the global data set have the potential to enhance the resolution of velocity structure. We compare GLAD-M25 and SEMUCB-WM1 by cross-validation with a new, independent, data set. Our results reveal that short- and long-wavelength structure is captured differently by the two models. Our findings lead us to recommend focusing future model iteration on and around the Pacific Superswell and adding data that sample new corridors, especially using ocean sensors, to better constrain seismic velocity structure in this area of significant geodynamic complexity.},
	issn = {1365-246X},
	doi = {10.1093/gji/ggaf044},
	url = {https://doi.org/10.1093/gji/ggaf044},
	author = {Wamba, Mathurin D and Simons, Frederik J and Irving, Jessica C E}
}
@article {anderson_deformation_2025,
	title = {Deformation on Rainbow Massif, Mid-Atlantic Ridge, Illuminated With Microearthquakes Detected by Machine Learning},
	journal = {Geophysical Research Letters},
	volume = {52},
	number = {2},
	year = {2025},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024GL111285},
	pages = {e2024GL111285},
	abstract = {Abstract Oceanic detachment fault systems are characteristic of slow-spreading mid-ocean ridges, where reduced magma supply leads to increased extension by faulting and exhumation of oceanic core complexes (OCCs). OCCs have complicated structure reflecting the interplay between magmatic, hydrothermal, and tectonic processes. We use microearthquake data from a 9-month ocean bottom seismometer deployment to image deformation structures in the Rainbow massif on the Mid-Atlantic Ridge. Using a machine-learning enabled workflow to obtain an earthquake catalog containing > {\vphantom} > \textbackslash68,000 events, we find seismicity occurred in distinct clusters that correlate with previously imaged velocity anomalies and dipping subsurface reflections. Our results are consistent with a dipping alteration front within the massif overlying late-stage intrusions and suggest a transpressional fault accommodates a non-transform offset north of the massif. Our results demonstrate OCCs continue to deform in a complex way after a detachment fault has been abandoned due to combined effects of tectonic stresses, magmatism, and alteration.},
	keywords = {detachment faults, machine learning, microearthquakes, oceanic core complex, slow spreading mid-ocean ridges},
	doi = {https://doi.org/10.1029/2024GL111285},
	author = {Anderson, Evan C. and Parnell-Turner, Ross and Sohn, Robert A. and Fan, Wenyuan}
}
@article {ashraf_high-resolution_2025,
	title = {A High-Resolution 3-D P-Wave Velocity Structure of the South-Central Cascadia Subduction Zone From Wide-Angle Shore-Crossing Seismic Refraction Data},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {130},
	number = {2},
	year = {2025},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024JB029525},
	pages = {e2024JB029525},
	abstract = {Abstract This study addresses a significant gap in understanding the features of the south-central Cascadia subduction zone, a region characterized by complex geologic, tectonic, and seismic transitions both offshore and onshore. Unlike other segments along this margin, this area lacks a 3-D velocity model to delineate its structural and geological features on a fine scale. To address this void, we developed a high-resolution 3-D P-wave velocity model using active source seismic data from ship-borne seismic shots recorded on temporary and permanent onshore seismic stations and ocean-bottom seismometers. Our model shows velocity variations across the region with distinct velocity-depth profiles for the Siletz, Franciscan, and Klamath terranes in the overlying plate. We identified seaward dipping high-velocity static backstops associated with the Siletz and Klamath terranes, situated near the shoreline and further inland, respectively. Regions of reduced crustal velocity are associated with crustal faults. Moreover, there is significant along-strike depth variation in the subducting slab, which is about 4 km deeper near the thick, dense Siletz terrane and becomes shallower near the predominantly less-dense Franciscan terrane. This highlights a sudden tectonic and geologic transition at the southern boundary of the Siletz terrane. Our velocity model also indicates slightly increased hydration, though still minimal, in both the oceanic crust and the upper mantle of the subducting plate compared to other parts of the margin.},
	doi = {https://doi.org/10.1029/2024JB029525},
	author = {Ashraf, Asif and Hooft, Emilie E. E. and Toomey, Douglas R. and Tr{\'e}hu, Anne M. and Nolan, Sarah and Wirth, Erin A. and Ward, Kevin M.}
}
@article {cortes-rivas_interactions_2025,
	title = {Interactions between megathrust behavior and forearc deformation in the Andreanof segment of the Aleutian Subduction Zone, offshore Alaska, USA},
	journal = {Geology},
	year = {2025},
	note = {_eprint: https://pubs.geoscienceworld.org/gsa/geology/article-pdf/doi/10.1130/G52810.1/7093527/g52810.pdf},
	abstract = {To explore controls on megathrust behavior and its connection with forearc deformation, we studied the Andreanof segment of the Aleutian Subduction Zone (offshore Alaska, USA), which has a simple geological history as a relatively young intra-oceanic subduction zone. Here, the forearc shows greater uplift and compression in the strongly coupled Adak region compared to the weakly coupled Atka region. Using multichannel seismic reflection data, we found that the incoming plate in both regions exhibits similar characteristics along the segment, suggesting that its properties do not account for the varying megathrust behavior and forearc deformation. Instead, differences between the Atka and Adak regions in the thickness of the methane hydrate stability zone, as marked by a bottom-simulating reflector, suggest more heat advection, and thus dewatering, in the Adak region, where the more developed fault network may enable fluid drainage, thereby lowering pore pressure at the megathrust and promoting coupling. Higher coupling allows for seismic and stress cycling that would sustain forearc permeability by faulting. Our results suggest a feedback between deformation and coupling that may be active or latent in other more complex subduction zones but in concert with or masked by other factors.},
	issn = {0091-7613},
	doi = {10.1130/G52810.1},
	url = {https://doi.org/10.1130/G52810.1},
	author = {Cort{\'e}s-Rivas, Valeria and Shillington, Donna J. and Lizarralde, Dan and Mark, Hannah}
}
@article {park_low-velocity_2025,
	title = {Low-velocity anomaly in the Coral Sea associated with subducting slabs and the Woodlark rift},
	journal = {Communications Earth \& Environment},
	volume = {6},
	number = {1},
	year = {2025},
	pages = {184},
	abstract = {Classical plume models offer insights into intraplate volcanism and seamount chain formation by assuming a cylindrical upwelling of hot materials from the core-mantle boundary. The interaction of mantle plumes with ridges or subducting slabs disrupts typical plate tectonics, leading to distinctive tectonic phenomena such as ridge jumps or slab stagnation. However, thermal plume models sometimes fall short in explaining perplexing tectonic features, necessitating consideration of compositional heterogeneities within mantle plumes. Here, using multimode waveform tomography, we identify a large, vertically divergent low-velocity anomaly in the upper mantle beneath the Coral Sea in the southwestern Pacific, which circumvents the remnants of subducting slabs toward northeastern Australia with intraplate volcanism, and the Woodlark rift, the most rapidly extending continental rift. Our findings furnish seismic evidence for the widespread propagation of a thermochemical mantle plume spanning over 10{\textdegree} at depths of 270{\textendash}410 km, facilitating its simultaneous contacts with slabs and rifts.},
	issn = {2662-4435},
	doi = {10.1038/s43247-025-02166-8},
	url = {https://doi.org/10.1038/s43247-025-02166-8},
	author = {Park, Ji-hoon and Chang, Sung-Joon}
}
@article {macleod_nonseismic_2025,
	title = {Nonseismic Short-Duration Events Offshore Cascadia: Characteristics and Potential Origin},
	journal = {Seismological Research Letters},
	volume = {96},
	number = {2A},
	year = {2025},
	pages = {706{\textendash}720},
	abstract = {Ocean-bottom seismometers (OBS) often record nonearthquake signals termed short-duration events (SDEs) that are typically recorded on one station with durations of \~{}1~s and frequencies between 4 and 30~Hz. Their origin has been attributed to animals bumping the sensor and a variety of physical mechanisms, including the passage of methane bubbles through sediments and across the seafloor. We analyzed records from OBSs deployed on the Cascadia margin and Juan de Fuca plate for the occurrence and characteristics of SDEs. SDEs are observed on all OBSs at rates that vary by over two orders of magnitude. The rates vary significantly at any given depth but on average decrease with increasing depth. The rates are low on buried sensors. For some unburied sensors, the rates are dependent on diurnal and/or tidal cycles. Strongly diurnally dependent rates for several OBSs on the continental shelf and upper slope with more SDEs during the day, are evidence of a biological mechanism for some SDEs. The presence of SDEs on buried sensors requires a physical mechanism for others. Because the decrease of SDE rates with depth is broadly consistent with both the expected variation in benthic animal densities and the emission of methane bubbles from the seafloor, it is not possible to infer the relative importance of biological and physical mechanisms. Experiments with cameras observing the sensor could be supported by cabled observatories and would provide a means to address this issue.},
	issn = {0895-0695},
	doi = {10.1785/0220240367},
	url = {https://doi.org/10.1785/0220240367},
	author = {MacLeod, Leo M. F. and Wilcock, William S. D.}
}
@article {niklasson_seafloor_2025,
	title = {Seafloor Seismic Noise Patterns Across the Pacific Basin},
	journal = {Seismological Research Letters},
	volume = {96},
	number = {2A},
	year = {2025},
	month = {feb},
	pages = {772{\textendash}783},
	abstract = {Seismic hazard monitoring and global tomography efforts are improved by recording signals at a variety of distances and azimuths to maximize subsurface sampling. Although seismic networks provide good to excellent coverage on land, seafloor stations are still sparse. Inclusion of ocean-based data would greatly improve the global coverage of seismic networks, but the use of seafloor seismic data to complement land-based detection and characterization of events is complicated by the generally much higher ambient noise level in the ocean compared to that observed on land. This noise is driven primarily by sea surface waves and tides, but how seismic noise levels vary with location in the oceans is not well described. Here, we analyze the relationship between ocean surface wave height and seismic noise in the 0.4{\textendash}4~Hz frequency band at ocean-bottom seismometer deployments across the Pacific basin. We find that a noise-to-responsiveness ratio (NRR){\textemdash}the median noise level at a station divided by its sea surface wave height responsiveness{\textemdash}correlates negatively with detection success for large teleseismic earthquakes. Stations that are close to land, with relatively shallow ocean and low wind speed, often have lower NRR than open-ocean stations, but the connection between geographic location and earthquake detection success is imperfect.},
	issn = {0895-0695},
	doi = {10.1785/0220240361},
	url = {https://doi.org/10.1785/0220240361},
	author = {Niklasson, Siobhan and Rowe, Charlotte and Bilek, Susan}
}
@article {wang_slab_2025,
	title = {Slab Morphology, Dehydration, and Sub-Arc Melting Beneath the Alaska Peninsula Revealed by Body-Wave Tomography},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {130},
	number = {3},
	year = {2025},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024JB029814},
	pages = {e2024JB029814},
	abstract = {Abstract The Alaska Peninsula has a long history of plate subduction with along-arc variations in volcanic eruption styles and geochemistry. However, the sub-arc melting processes that feed these volcanoes are unclear. The Alaska slab morphology below 200 km depth remains debated due to limited seismic data and thus low tomography resolution in this region. Here we utilize the newly available regional and teleseismic data to build 3-D high-resolution VP and VS models to 660 km depth. We find that the high-velocity Pacific Plate subducts to the bottom of the mantle transition zone (MTZ) with complex deformation and gaps. In the southwest, we observe a wide gap in the high-velocity slab at 200{\textendash}500 km depths. Toward the northeast, the slab becomes more continuous extending to the MTZ with a few holes below 200 km. We interpret these gaps as a slab tear that coincides with the subducted ancient Kula-Pacific Ridge. We also invert for 3-D VP and VP/VS models to 200 km depth with higher resolution and find strong along-strike changes in slab dehydration and sub-arc melting, indicated by low VP and high VP/VS anomalies. Slab dehydration and sub-arc melting are most extensive below the Pavlof and Shumagin segments in the southwest, becoming limited below the Chignik and Chirikof segments in the northeast, and extensive again beneath the Kodiak segment further to the northeast. We propose that the variations of slab hydration at the outer rise significantly influence slab dehydration at greater depths and further control sub-arc melting beneath the Alaska Peninsula.},
	keywords = {Alaska peninsula, Body-wave tomography, slab dehydration, slab morphology, sub-arc melting, subduction zones, tomography, volcano},
	doi = {https://doi.org/10.1029/2024JB029814},
	author = {Wang, Fan and Wei, S. Shawn and Ruppert, Natalia A. and Zhang, Haijiang and Wu, Jonny}
}
@article {gase_toques_2025,
	title = {TOQUES: An Ocean-Bottom Seismometer Dataset on the Central Queen Charlotte Fault, Southeast Alaska},
	journal = {Seismological Research Letters},
	year = {2025},
	month = {mar},
	abstract = {Plate boundaries in the oceans are often poorly monitored. Though typically less remote than the deep sea, shallow marine environments with seafloor depths \&lt;0.5~km can be especially challenging for seismic experiments due to natural and anthropogenic hazards and noise sources that can affect instrument survival and data quality. The Queen Charlotte fault (QCF) is part of a transform plate boundary that follows the continental shelf of the Alaska Panhandle and central British Columbia. This fault system accommodates dextral slip between the Pacific and North American plates and has hosted several historic Mw \&gt; 7 earthquakes. In August 2021, we deployed 28 broadband ocean-bottom seismometers (OBSs) along the central QCF for the {\textquotedblleft}Transform Obliquity along the Queen Charlotte Fault and Earthquake Study{\textquotedblright} (TOQUES) to investigate fault architecture and local seismicity. Deployment depths varied between 0.2 and 2.5~km below sea level, with half of the instruments deployed in shallow water (\&lt;0.5~km depth). We describe the scientific motivations for the TOQUES broadband OBS array, present data metrics, and discuss factors that influence data quality and instrument survival. We show that many opportunities exist for scientific study of shallow marine environments and the solid earth. Despite concerns that shallow water was responsible for the risk of data or instrument loss, direct relationships between instrument success and water depth are inconclusive. Rather, instrument success may be more related to the ability of different instrument designs to withstand shallow-water conditions.},
	issn = {0895-0695},
	doi = {10.1785/0220240380},
	url = {https://doi.org/10.1785/0220240380},
	author = {Gase, Andrew C. and Roland, Emily C. and Worthington, Lindsay L. and Walton, Maureen A. L. and Bostock, Michael G. and Nedimovi{\'c}, Mladen R. and Collins, John A. and Brandl, Collin C. and Jaye Oliva, Sarah and Sun, Tianhaozhe}
}
@article {li_along-strike_2024,
	title = {Along-Strike Variations of Alaska Subduction Zone Structure and Hydration Determined From Amphibious Seismic Data},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {129},
	number = {3},
	year = {2024},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2023JB027800},
	pages = {e2023JB027800},
	abstract = {We develop a 3-D isotropic shear velocity model for the Alaska subduction zone using data from seafloor and land-based seismographs to investigate along-strike variations in structure. By applying ambient noise and teleseismic Helmholtz tomography, we derive Rayleigh wave group and phase velocity dispersion maps, then invert them for shear velocity structure using a Bayesian Monte Carlo algorithm. For land-based stations, we perform a joint inversion of receiver functions and dispersion curves. The forearc crust is relatively thick (35{\textendash}42 km) and has reduced lower crustal velocities beneath the Kodiak and Semidi segments, which may promote higher seismic coupling. Bristol Bay Basin crust is relatively thin and has a high-velocity lower layer, suggesting a dense mafic lower crust emplaced by the rifting processes. The incoming plate shows low uppermost mantle velocities, indicating serpentinization. This hydration is more pronounced in the Shumagin segment, with greater velocity reduction extending to 18 {\textpm} 3 km depth, compared to the Semidi segment, showing smaller reductions extending to 14 {\textpm} 3 km depth. Our estimates of percent serpentinization from VS reduction and VP/VS are larger than those determined using VP reduction in prior studies, likely due to water in cracks affecting VS more than VP. Revised estimates of serpentinization show that more water subducts than previous studies, and that twice as much mantle water is subducted in the Shumagin segment compared to the Semidi segment. Together with estimates from other subduction zones, the results indicate a wide variation in subducted mantle water between different subduction segments.},
	keywords = {Alaska subduction zone, along-strike variation, forearc crustal thickness, incoming plate hydration, seismic tomography},
	issn = {2169-9356},
	doi = {10.1029/2023JB027800},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023JB027800},
	author = {Li, Zongshan and Wiens, Douglas A. and Shen, Weisen and Shillington, Donna J.}
}
@article {kim_application_2024,
	title = {Application of the reverberation waveform inversion for the high-resolution sediment layer structure in the Pacific},
	journal = {Geophysical Journal International},
	volume = {240},
	number = {2},
	year = {2024},
	note = {_eprint: https://academic.oup.com/gji/article-pdf/240/2/1331/61230955/ggae444.pdf},
	pages = {1331{\textendash}1344},
	abstract = {This study presents the velocity structures of the seafloor sediment across the Pacific using teleseismic body waves recorded by arrays of ocean bottom seismometers (OBSs). We apply the method inverting the multicomponent stacked autocorrelation functions and radial-component waveform of teleseismic body waves. We analyze OBSs distributed across the Pacific Ocean, through a wide range of water depths and equipped with various sensor types. The inverted models agreeing with measurements of seafloor drilling samples demonstrate the broad applicability of employing the inversion method to resolve sediment thicknesses ranging from \&lt;100 m to a few kilometers. In addition to various broad-band OBSs, we confirm our method works also for short-period sensors, since our retrieved the model using data from a short-period sensor in Northeast Japan agrees with active-source seismic survey analyses. The constrained models show various numbers of intrasediment discontinuities across different locations. Furthermore, the newly characterized sediment models have higher values of P-wave to S-wave velocity ratio ({{V}_P}\textbackslash/{{V}_S}\textbackslash) than the previously known scaling relationships, which suggests a larger effect of sediment-layer reverberation on the body-wave analysis than we have anticipated. The sediment velocity models obtained in this study produce Rayleigh-wave admittances that are consistent with those in previous studies but with much finer structural details within the sediment layer. The reverberation waveform inversion method will enable improved predictions of the impact of the water and sediment layers in body-wave records from existing and future OBS observations.},
	issn = {1365-246X},
	doi = {10.1093/gji/ggae444},
	url = {https://doi.org/10.1093/gji/ggae444},
	author = {Kim, HyeJeong and Kawakatsu, Hitoshi and Akuhara, Takeshi and Takeuchi, Nozomu and Isse, Takehi and Shiobara, Hajime and Sugioka, Hiroko and Utada, Hisashi and Kim, YoungHee and Lee, Sang-Mook}
}
@article {zheng_characterizing_2024,
	title = {Characterizing Sub-Seafloor Seismic Structure of the Alaska Peninsula Along the Alaska-Aleutian Subduction Zone},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {129},
	number = {11},
	year = {2024},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024JB029862},
	pages = {e2024JB029862},
	abstract = {Abstract A shallow sub-seafloor seismic model that includes well-determined seismic velocities and clarifies sediment-crust discontinuities is needed to characterize the physical properties of marine sediments and the oceanic crust and to serve as a reference for deeper seismic modeling endeavors. This study estimates the seismic structure of marine sediments and the shallow oceanic crust of the Alaska-Aleutian subduction zone at the Alaska Peninsula, using data from the Alaska Amphibious Community Seismic Experiment (AACSE). We measure seafloor compliance and Ps converted wave delays from AACSE ocean-bottom seismometers (OBS) and seafloor pressure data and interpret these measurements using a joint Bayesian Monte Carlo inversion to produce a sub-seafloor S-wave velocity model beneath each available OBS station. The sediment thickness across the array varies considerably, ranging from about 50 m to 2.80 km, with the thickest sediment located in the continental slope. Lithological composition plays an important role in shaping the seismic properties of seafloor sediment. Deep-sea deposits on the incoming plate, which contain biogenic materials, tend to have reduced S-wave velocities, contrasting with the clay-rich sediments in the shallow continental shelf and continental slope. A difference in S-wave velocities is observed for upper oceanic crust formed at fast-rate (Shumagin) and intermediate-rate (Semidi) spreading centers. The reduced S-wave velocities in the Semidi crust may be caused by increased faulting and possible lithological variations, related to a previous period of intermediate-rate spreading.},
	keywords = {Alaska peninsula, seafloor compliance, sub-seafloor structure},
	doi = {https://doi.org/10.1029/2024JB029862},
	author = {Zheng, Mengjie and Sheehan, Anne F. and Liu, Chuanming and Wu, Mengyu and Ritzwoller, Michael H.}
}
@article {xi_deep_2024,
	title = {Deep Learning for Deep Earthquakes: Insights from OBS Observations of the Tonga Subduction Zone},
	journal = {Geophysical Journal International},
	volume = {238},
	number = {2},
	year = {2024},
	month = {08/2024},
	pages = {1073{\textendash}1088},
	abstract = {Applications of machine learning in seismology have greatly improved our capability of detecting earthquakes in large seismic data archives. Most of these efforts have been focused on continental shallow earthquakes, but here we introduce an integrated deep-learning-based workflow to detect deep earthquakes recorded by a temporary array of ocean-bottom seismographs (OBSs) and land-based stations in the Tonga subduction zone. We develop a new phase picker, PhaseNet-TF, to detect and pick P- and S-wave arrivals in the time-frequency domain. The frequency-domain information is critical for analyzing OBS data, particularly the horizontal components, because they are contaminated by signals of ocean-bottom currents and other noise sources in certain frequency bands. PhaseNet-TF shows a much better performance in picking S waves at OBSs and land stations compared to its predecessor PhaseNet. The predicted phases are associated using an improved Gaussian Mixture Model Associator GaMMA-1D and then relocated with a double-difference package teletomoDD. We further enhance the model performance with a semi-supervised learning approach by iteratively refining labelled data and retraining PhaseNet-TF. This approach effectively suppresses false picks and significantly improves the detection of small earthquakes. The new catalogue of Tonga deep earthquakes contains more than 10~times more events compared to the reference catalogue that was analyzed manually. This deep-learning-enhanced catalogue reveals Tonga seismicity in unprecedented detail, and better defines the lateral extent of the double-seismic zone at intermediate depths and the location of 4 large deep-focus earthquakes relative to background seismicity. It also offers new potential for deciphering deep earthquake mechanisms, refining tomographic models, and understanding of subduction processes.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggae200},
	url = {https://doi.org/10.1093/gji/ggae200},
	author = {Xi, Ziyi and Wei, S Shawn and Zhu, Weiqiang and Beroza, Gregory C and Jie, Yaqi and Saloor, Nooshin}
}
@article {watts_effective_2024,
	title = {The effective elastic thickness along the Emperor Seamount Chain and its tectonic implications},
	journal = {Geophysical Journal International},
	volume = {240},
	number = {1},
	year = {2024},
	note = {_eprint: https://academic.oup.com/gji/article-pdf/240/1/61/60814731/ggae372.pdf},
	pages = {61{\textendash}80},
	abstract = {The Hawaiian{\textendash}Emperor Seamount Chain, a pre-eminent example of a hotspot-generated intraplate seamount chain, provides key constraints not only on the kinematics of plates but also on their rigidity. Previous studies have shown that the effective elastic thickness, Te, a proxy for the long-term strength of the lithosphere, changes abruptly at the Hawaiian{\textendash}Emperor {\textquoteleft}bend{\textquoteright} from low values (\~{}16 km) at the Emperor Seamounts to high values (\~{}27 km) at the Hawaiian Ridge. To better constrain Te along the poorly explored Emperor Seamounts we have used a free-air gravity anomaly and bathymetry gridded data set, together with fully 3-D elastic plate (flexure) models, to estimate the continuity of Te and volcano load and infill densities along 1000 profiles spaced 2 km apart of the chain. Results show that Te generally decreases northwards along the chain. The decrease is most systematic between Ojin and Jimmu guyots where Te depends on the age of the lithosphere at the time of volcano loading and is controlled by the 340 and 400 {\textdegree}C oceanic isotherms. The largest variation from these isotherms occurs at the northern and southern ends of the chain where Te is smaller than expected suggesting the influence of pre-existing, older, loads. We use these results to constrain the subsidence, flexural tilt, rheological properties and tectonic setting along the seamount chain. We found an excess subsidence in the range 1.2{\textendash}2.4 km, a tilt as large as 2{\textendash}3{\textdegree}, oceanic lithosphere that is weaker than it is seawards of the weak zone at subduction zones, and a tectonic setting at Detroit and Koko seamounts that, despite their forming an integral part of the hotspot generated seamount chain, retains a memory of their proximity to earlier loads associated with plume influenced mid-oceanic ridges.},
	issn = {1365-246X},
	doi = {10.1093/gji/ggae372},
	url = {https://doi.org/10.1093/gji/ggae372},
	author = {Watts, Anthony B and Wessel, P{\r a}l and Xu, Chong}
}
@article {hilmo_estimating_2024,
	title = {Estimating distances to baleen whales using multipath arrivals recorded by individual seafloor seismometers at full ocean depth},
	journal = {The Journal of the Acoustical Society of America},
	volume = {155},
	number = {2},
	year = {2024},
	month = {02/2024},
	pages = {930{\textendash}951},
	chapter = {930},
	abstract = {Ocean bottom seismometer networks can record opportunistic data sets of 20-Hz fin whale calls. Because networks are often too sparse for multi-station tracking, single-station methods are needed to estimate call density. We investigated a method to range to singing fin whales at full ocean depths using the spacing of water column multiples. Calls were detected by cross-correlating a spectrogram with a template call. To enhance multipath signals, we considered 20-min windows and either summed the spectrograms of all calls aligned on the strongest detection before measuring the multipath spacing or measured the spacing directly from the autocorrelation of the cross correlation time series. We evaluated the methods at five sites with contrasting seafloor and subsurface properties, bathymetric relief, and water depths of 4000{\textendash}6000 m, using fin whale songs at four sites and a sei whale song at the fifth. The autocorrelation method works best, and ranges can be obtained to \&gt;15 km. Ranging at sedimented sites requires careful accounting for subsurface reflections. Ranges have considerable uncertainty in regions of bathymetric relief. The method requires that the time between calls is different from that of the multipaths and does not work reliably when more than one whale is singing nearby.},
	issn = {0001-4966},
	doi = {10.1121/10.0024615},
	url = {https://doi.org/10.1121/10.0024615},
	author = {Hilmo, Rose and Wilcock, William S. D.}
}
@article {wang_fluids_2024,
	title = {Fluids control along-strike variations in the Alaska megathrust slip},
	journal = {Earth and Planetary Science Letters},
	volume = {633},
	year = {2024},
	month = {may},
	pages = {118655},
	abstract = {Interseismic and coseismic slip on the subduction zone megathrust show complex along-strike variations and the controlling factors remain debated. Here we image seismic velocity anomalies to infer fluid distribution in the Alaska subduction zone (Alaska Peninsula section) with seismic tomography. The weakly locked Shumagin segment is characterized by abundant fluids on the plate interface and in the overriding plate, whereas the moderately-to-highly locked Chignik and Chirikof segments that hosted M > 8 earthquakes are relatively dry. The Kodiak segment, which was ruptured by the 1964 M9.2 Great Alaska earthquake and is presently fully locked near the trench, is characterized by a fluid-rich plate interface but a fluid-poor and inferred low-porosity overriding plate. Multiple large earthquakes have nucleated in fluid-rich regions at the plate interface. Our study highlights the important roles of fluids, particularly in the overriding plate, in controlling interseismic slip deficit and earthquake rupture. We propose that a fluid-rich overriding plate means that there has been a high sustained flux of fluids across the plate interface, which enhances the formation of clay minerals that promote fault creep.},
	keywords = {Alaska peninsula, Body-wave tomography, fluids, Megathrust earthquakes, Slip behavior, subduction zone},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2024.118655},
	url = {https://www.sciencedirect.com/science/article/pii/S0012821X24000888},
	author = {Wang, Fan and Wei, S. Shawn and Drooff, Connor and Elliott, Julie L. and Freymueller, Jeffrey T. and Ruppert, Natalia A. and Zhang, Haijiang}
}
@article {atkins_hydroacoustic_2024,
	title = {Hydroacoustic Evidence for Offshore Lava Emplacement During the 2018 Kilauea Eruption},
	journal = {Geophysical Research Letters},
	volume = {51},
	number = {20},
	year = {2024},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024GL110885},
	month = {10/2024},
	pages = {e2024GL110885},
	abstract = {During the 2018 Kilauea eruption, over half the erupted lava was deposited on the seafloor. Lava flows crossing the shoreline generated sounds that were recorded by a network of hydrophones. We show that short-duration, broadband signals associated with lava-water interactions occurred throughout the eruption but increased in number when the Ahalanui ocean entry initiated on July 11. These terminated in early August coincident with the eruption{\textquoteright}s end. We compare hydroacoustic data with transmission loss models and eruption photographs to show that coastal explosive activity was poorly recorded by the hydrophone network. Similarly, strong hydroacoustic signals did not correlate with observed activity. These results suggest that acoustic signals were generated by lava flowing up to 100 s of meters offshore. Offshore lava flows can be hazardous to boaters, but hydrophones provide a means by which these hazards can be detected.},
	keywords = {hydrophone, hydrovolcanic, Kilauea, lava-water interaction},
	issn = {1944-8007},
	doi = {10.1029/2024GL110885},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2024GL110885},
	author = {Atkins, C. and Costa, O. and Caplan-Auerbach, J.}
}
@article {jian_hydrothermal_2024,
	title = {Hydrothermal flow and serpentinization in oceanic core complexes controlled by mafic intrusions},
	journal = {Nature Geoscience},
	year = {2024},
	note = {Publisher: Nature Publishing Group},
	pages = {1{\textendash}6},
	abstract = {Deep-sea hydrothermal systems at slow/ultraslow-spreading mid-ocean ridges are often located within ultramafic rocks that are part of oceanic core complexes. These complexes contain lower-crustal and mantle sections exhumed due to detachment faulting. Hydrothermal circulation in these environments leads to massive sulfide deposits, hydration of oceanic lithosphere and conditions resembling early Earth{\textquoteright}s life origin. However, the relationship between hydrothermal pathways in these environments and crustal and mantle lithologies, faulting, magmatism, serpentinization and alteration is poorly understood. Here we present seismic models of a Mid-Atlantic Ridge core complex and its ultramafic-hosted hydrothermal system derived from full waveform inversion of controlled-source seismic data and from local earthquake tomography. The models and derived rock properties reveal high-permeability channels within serpentinized peridotite along the flanks of the core complex. These channels converge beneath active and fossil hydrothermal fields and are diverted around mechanically strong, impermeable shallow mafic intrusions (2{\textendash}3 km wide, \textasciitilde1 km thick), causing hydrothermal outflow and the formation of massive sulfide deposits around the intrusions{\textquoteright} edges. These mafic intrusions also act as lids that limit fluid downflow{\textemdash}and thus serpentinization{\textemdash}in the centre of the core complex. Our results demonstrate that hydrothermal flow in ultramafic settings is controlled by lithology contacts, with mafic intrusions modulating hydrothermal pathways and extent of mantle serpentinization at depth.},
	keywords = {3706 Geophysics, Economic geology, Element cycles, Geodynamics, Tectonics},
	issn = {1752-0908},
	doi = {10.1038/s41561-024-01444-y},
	url = {https://www.nature.com/articles/s41561-024-01444-y},
	author = {Jian, Hanchao and Canales, J. Pablo and Dunn, Robert and Nedimovi{\'c}, Mladen R.}
}
@article {oryan_megathrust_2024,
	title = {Megathrust locking encoded in subduction landscapes},
	journal = {Science Advances},
	volume = {10},
	number = {17},
	year = {2024},
	note = {Publisher: American Association for the Advancement of Science},
	pages = {eadl4286},
	abstract = {Locked areas of subduction megathrusts are increasingly found to coincide with landscape features sculpted over hundreds of thousand years, yet the mechanisms that underlie such correlations remain elusive. We show that interseismic locking gradients induce increments of irreversible strain across the overriding plate manifested predominantly as distributed seismicity. Summing these increments over hundreds of earthquake cycles produces a spatially variable field of uplift representing the unbalance of co-, post-, and interseismic strain. This long-term uplift explains first-order geomorphological features of subduction zones such as the position of the continental erosive shelf break, the distribution of marine terraces and peninsulas, and the profile of forearc rivers. Inelastic yielding of the forearc thus encodes short-term locking patterns in subduction landscapes, hinting that megathrust locking is stable over multiple earthquake cycles and highlighting the role geomorphology can play in constraining Earth{\textquoteright}s greatest source of seismic hazard.},
	doi = {10.1126/sciadv.adl4286},
	url = {https://www.science.org/doi/10.1126/sciadv.adl4286},
	author = {Oryan, Bar and Olive, Jean-Arthur and Jolivet, Romain and Malatesta, Luca C. and Gailleton, Boris and Bruhat, Lucile}
}
@article {chen_mid-lithospheric_2024,
	title = {A Mid-Lithospheric Discontinuity Detected Beneath 155 Ma Western Pacific Seafloor Using Sp Receiver Functions},
	journal = {Geophysical Research Letters},
	volume = {51},
	number = {5},
	year = {2024},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2024GL108347},
	pages = {e2024GL108347},
	abstract = {This study probes the lithosphere-asthenosphere system beneath 155 Ma Pacific seafloor using teleseismic S-to-p receiver functions at the Pacific Lithosphere Anisotropy and Thickness Experiment project ocean-bottom-seismometers. Within the lithosphere, a significant velocity decrease at 33{\textendash}50 km depth is observed. This mid-lithospheric discontinuity is consistent with the velocity contrast between the background mantle and thin, trapped layers of crystallized partial melt, in the form of either dolomite or garnet granulite. These melts possibly originated from deeper asthenospheric melting beneath the flanks of spreading centers, and were transported within the cooling lithosphere. A positive velocity increase of 3\%{\textendash}6\% is observed at 130{\textendash}155 km depth and is consistent with the base of a layer with partial melt in the asthenosphere. A shear velocity decrease associated with the lithosphere-asthenosphere boundary at 95{\textendash}115 km depth is permitted by the data, but is not required.},
	keywords = {oceanic lithosphere and asthenosphere, old western Pacific, partial melt, PLATE OBS array, Sp receiver function},
	issn = {1944-8007},
	doi = {10.1029/2024GL108347},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2024GL108347},
	author = {Chen, K.-X. and Forsyth, D. W. and Fischer, K. M.}
}
@article {niksejel_obstransformer_2024,
	title = {OBSTransformer: A Deep-Learning Seismic Phase Picker for OBS Data Using Automated Labelling and Transfer Learning},
	journal = {Geophysical Journal International},
	year = {2024},
	pages = {ggae049},
	abstract = {Accurate seismic phase detection and onset picking are fundamental to seismological studies. Supervised deep-learning phase pickers have shown promise with excellent performance on land seismic data. Although it may be acceptable to apply them to OBS (Ocean Bottom Seismometer) data that are indispensable for studying ocean regions, they suffer from a significant performance drop. In this study, we develop a generalised transfer-learned OBS phase picker {\textendash} OBSTransformer, based on automated labelling and transfer learning. First, we compile a comprehensive dataset of catalogued earthquakes recorded by 423 OBSs from 11 temporary deployments worldwide. Through automated processes, we label the P and S phases of these earthquakes by analysing the consistency of at least three arrivals from four widely used machine learning pickers (EQTransformer, PhaseNet, Generalized Phase Detection, and PickNet), as well as the AIC (Akaike Information Criterion) picker. This results in an inclusive OBS dataset containing \~{}36,000 earthquake samples. Subsequently, we employ this dataset for transfer learning and utilize a well-trained land machine learning model {\textendash} EQTransformer as our base model. Moreover, we extract 25,000 OBS noise samples from the same OBS networks using the Kurtosis method, which are then used for model training alongside the labelled earthquake samples. Using three groups of test datasets at sub-global, regional, and local scales, we demonstrate that OBSTransformer outperforms EQTransformer. Particularly, the P and S recall rates at large distances (\&gt;200 km) are increased by 68\% and 76\%, respectively. Our extensive tests and comparisons demonstrate that OBSTransformer is less dependent on the detection/picking thresholds and is more robust to noise levels.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggae049},
	url = {https://doi.org/10.1093/gji/ggae049},
	author = {Niksejel, Alireza and Zhang, Miao}
}
@article {cones_offshore_2024,
	title = {Offshore windfarm construction elevates metabolic rate and increases predation vulnerability of a key marine invertebrate},
	journal = {Environmental Pollution},
	volume = {360},
	year = {2024},
	month = {11/2024},
	pages = {124709},
	abstract = {A global increase in offshore windfarm development is critical to our renewable energy future. Yet, widespread construction plans have generated substantial concern for impacts to co-occurring organisms and the communities they form. Pile driving construction, prominent in offshore windfarm development, produces among the highest amplitude sounds in the ocean creating widespread concern for a diverse array of taxa. However, studies addressing ecologically key species are generally lacking and most research is disparate, failing to integrate across response types (e.g., behavior, physiology, and ecological interactions), particularly in situ. The lack of integrative field studies presents major challenges to understand or mitigate actual impacts of offshore wind development. Here, we examined critical behavioral, physiological, and antipredator impacts of actual pile driving construction on the giant sea scallop (Placopecten magellanicus). Benthic taxa including bivalves are of particular concern because they are sound-sensitive, cannot move appreciable distances away from the stressor, and support livelihoods as one of the world{\textquoteright}s most economically and socially important fisheries. Overall, pile driving sound impacted scallops across a series of behavioral and physiological assays. Sound-exposed scallops consistently reduced their valve opening (22\%), resulting in lowered mantle water oxygen levels available to the gills. Repeated and rapid valve adductions led to a 56\% increase in metabolic rates relative to pre-exposure baselines. Consequently, in response to predator stimuli, sound-exposed scallops displayed a suite of significantly weaker antipredator behaviors including fewer swimming events and shorter time-to-exhaustion. These results show aquatic construction activities can induce metabolic and ecologically relevant changes in a key benthic animal. As offshore windfarm construction accelerates globally, our field-based study highlights that spatial overlap with benthic taxa may cause substantial metabolic changes, alter important fisheries resources, and ultimately could lead to increased predation.},
	keywords = {Metabolism, noise, Predation, Scallop, Sound pollution},
	issn = {0269-7491},
	doi = {10.1016/j.envpol.2024.124709},
	url = {https://www.sciencedirect.com/science/article/pii/S0269749124014234},
	author = {Cones, Seth F. and J{\'e}z{\'e}quel, Youenn and Jarriel, Sierra and Aoki, Nad{\`e}ge and Brewer, Hannah and Collins, John and Chauvaud, Laurent and Mooney, T. Aran}
}
@article {chen_origin_2024,
	title = {On the Origin of the Hawaiian Swell: Lithosphere and Asthenosphere Seismic Structure From Rayleigh Wave Dispersion},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {129},
	number = {7},
	year = {2024},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2024JB029407},
	month = {07/2024},
	pages = {e2024JB029407},
	abstract = {In this study, we revisit the shear-wave velocity structure of the lithosphere and asthenosphere surrounding the Hawaiian hotspot and Hawaiian swell using Rayleigh wave data spanning periods of 20{\textendash}125 s from the PLUME project. A primary goal of this investigation is to probe the origin of the Hawaiian swell and the mechanism that elevates the topography, providing insights into mantle dynamics beneath hotspot swells. In the shear velocity model, the 30{\textendash}70 km depth range is largely featureless with weak and local anomalies, indicating that the elevation of the Hawaiian swell cannot be attributed to upper lithospheric reheating or replacement. In contrast, at 80{\textendash}150 km depth, a pronounced region of anomalously low velocities is well-resolved, with the lowest velocities found beneath the Hawaii-Maui-Molokai part of the island chain. Minimum shear velocities are approximately 4.0 km/s at 100{\textendash}120 km depth, which is an \~{}8\%-10\% velocity decrease relative to the surrounding velocities away from the swell. This pattern suggests that hot, buoyant mantle from deeper plume sources laterally spread out near the top of the normal oceanic asthenosphere. We find that the low-velocity pattern in the asthenosphere exhibits a strong correlation with the overall shape of the Hawaiian swell topography. Assuming that density anomalies are proportional to shear velocity anomalies, we demonstrate that the anomalous elevation of the swell can be explained by the uplift of a 30-km-thick elastic plate loaded from below by this buoyant, low-seismic-velocity layer in the asthenosphere.},
	keywords = {Hawaiian swell, lithosphere and asthenosphere, oceanic hotspot, Rayleigh wave, shear-wave velocity, two-plane wave method},
	issn = {2169-9356},
	doi = {10.1029/2024JB029407},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2024JB029407},
	author = {Chen, Kai-Xun and Forsyth, Donald W.}
}
@article {bornstein_pickblue_2024,
	title = {PickBlue: Seismic Phase Picking for Ocean Bottom Seismometers With Deep Learning},
	journal = {Earth and Space Science},
	volume = {11},
	number = {1},
	year = {2024},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2023EA003332},
	month = {11/2023},
	pages = {e2023EA003332},
	abstract = {Detecting phase arrivals and pinpointing the arrival times of seismic phases in seismograms is crucial for many seismological analysis workflows. For land station data, machine learning methods have already found widespread adoption. However, deep learning approaches are not yet commonly applied to ocean bottom data due to a lack of appropriate training data and models. Here, we compiled an extensive and labeled ocean bottom seismometer (OBS) data set from 15 deployments in different tectonic settings, comprising \~{}90,000 P and \~{}63,000 S manual picks from 13,190 events and 355 stations. We propose PickBlue, an adaptation of the two popular deep learning networks EQTransformer and PhaseNet. PickBlue joint processes three seismometer recordings in conjunction with a hydrophone component and is trained with the waveforms in the new database. The performance is enhanced by employing transfer learning, where initial weights are derived from models trained with land earthquake data. PickBlue significantly outperforms neural networks trained with land stations and models trained without hydrophone data. The model achieves a mean absolute deviation of 0.05 s for P-waves and 0.12 s for S-waves, and we apply the picker on the Hikurangi Ocean Bottom Tremor and Slow Slip OBS deployment offshore New Zealand. We integrate our data set and trained models into SeisBench to enable an easy and direct application in future deployments.},
	keywords = {machine learning, OBS seismicity database, ocean bottom seismometer, onset determination, phase picking},
	issn = {2333-5084},
	doi = {10.1029/2023EA003332},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023EA003332},
	author = {Bornstein, T. and Lange, D. and M{\"u}nchmeyer, J. and Woollam, J. and Rietbrock, A. and Barcheck, G. and Grevemeyer, I. and Tilmann, F.}
}
@article {zang_reciprocity-based_2024,
	title = {A Reciprocity-Based Efficient Method for Improved Source Parameter Estimation of Submarine Earthquakes With Hybrid 3-D Teleseismic Green{\textquoteright}s Functions},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {129},
	number = {5},
	year = {2024},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2023JB028174},
	month = {05/2024},
	pages = {e2023JB028174},
	abstract = {Accurate source parameters of global submarine earthquakes are essential for understanding earthquake mechanics and tectonic dynamics. Previous studies have demonstrated that teleseismic P coda waveform complexities due to near-source 3-D structures are highly sensitive to source parameters of marine earthquakes. Leveraging these sensitivities, we can improve the accuracy of source parameter inversion compared to traditional 1-D methods. However, modeling these intricate 3-D effects poses significant computational challenges. To address this issue, we propose a novel reciprocity-based hybrid method for computing 3-D teleseismic Green{\textquoteright}s functions. Based on this method, we develop a grid-search inversion workflow for determining reliable source parameters of moderate-sized submarine earthquakes. The method is tested and proven on five Mw5+ earthquakes at the Blanco oceanic transform fault (OTF) with ground truth locations resolved by a local ocean bottom seismometer array, using ambient noise correlation and surface-wave relocation techniques. Our results show that fitting P coda waveforms through 3-D Green{\textquoteright}s functions can effectively improve the source location accuracy, especially for the centroid depth. Our improved centroid depths indicate that all the five Mw5+ earthquakes on the Blanco transform fault ruptured mainly above the depth of 600{\textdegree}C isotherm predicted by the half-space cooling model. This finding aligns with the hypothesis that the rupture zone of large earthquakes at OTFs is confined by the 600{\textdegree}C isotherm. However, it is noted that the Blanco transform fault serves as a case study. Our 3-D source inversion method offers a promising tool for systematically investigating global oceanic earthquakes using teleseismic waves.},
	keywords = {14 Life Below Water, 3-D teleseismic Green{\textquoteright}s function, Blanco transform fault, improved source parameters, moderate-sized submarine earthquakes, reciprocity, SEM-DSM method},
	issn = {2169-9356},
	doi = {10.1029/2023JB028174},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023JB028174},
	author = {Zang, Chong and Wu, Wenbo and Ni, Sidao and Xu, Min}
}
@article {mark_refining_2024,
	title = {Refining the Extent and Depth of the Shear Zone Surrounding the Alpine Fault Using Receiver Function Harmonics},
	journal = {Geophysical Research Letters},
	volume = {51},
	number = {23},
	year = {2024},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024GL112092},
	pages = {e2024GL112092},
	abstract = {Abstract Large continental transform faults are thought to cross-cut the crust and extend into the lithospheric mantle. However, the strain distribution associated with these faults at mantle depths is not well understood. At the heart of this question is the rheology of the lithosphere: when stressed by displacement on a trans-crustal fault, does the uppermost mantle localize strain in a continuing narrow fault zone, or is that strain instead distributed in a shear zone that widens with increasing depth? This study uses harmonic decomposition of receiver functions to measure the spatial and depth distribution of seismic anisotropy, a proxy for viscous deformation, around the Alpine Fault in Aotearoa New Zealand. Anisotropy aligned with the fault is present in the lithosphere at least 100 km away from the fault trace, suggesting that the Alpine Fault shear zone widens at depth.},
	doi = {https://doi.org/10.1029/2024GL112092},
	author = {Mark, Hannah F.}
}
@article {rebeyrol_revisiting_2024,
	title = {Revisiting the OBS seafloor compliance signal removal with a stationarity and stacking-based approach: the BRUIT-FM toolbox},
	journal = {Geophysical Journal International},
	volume = {239},
	year = {2024},
	month = {10/2024},
	pages = {386{\textendash}401},
	abstract = {This study focuses on improving the seafloor compliance noise removal method, which relies on estimates of the compliance transfer function frequency response (the deformation of the seafloor under long-period pressure waves). We first propose a new multi-scale deviation analysis of broadband ocean bottom seismometer data to evaluate stationarity properties that are key to the subsequent analysis. We then propose a new approach to removing the compliance noise from the vertical channel data, by stacking daily estimated transfer function frequency responses over a period of time. We also propose an automated transient event detection and data selection method based on a cross-correlation criterion. As an example, we apply the method to data from the Cascadia Initiative (network 7D2011). We find that the spectral extent of long-period forcing waves varies significantly over time so that standard daily transfer function calculation techniques poorly estimate the transfer function frequency response at the lowest frequencies, resulting in poor denoising performance. The proposed method more accurately removes noise at these lower frequencies, especially where coherence is low, reducing the mean deviation of the signal in our test case by 27 \% or more. We also show that our calculated transfer functions can be transfered across time periods. The method should allow better estimates of seafloor compliance and help to remove compliance noise at stations with low pressure-acceleration coherence. Our results can be reproduced using the BRUIT-FM Python toolbox, available at https://gitlab.ifremer.fr/anr-bruitfm/bruit-fm-toolbox.},
	issn = {1365-246X},
	doi = {10.1093/gji/ggae265},
	url = {https://doi.org/10.1093/gji/ggae265},
	author = {Rebeyrol, Simon and Ker, St{\'e}phan and Duval, Laurent and Crawford, Wayne C}
}
@article {liu_seismic_2024,
	title = {Seismic Anisotropy and Deep Crustal Deformation Across Alaska},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {129},
	number = {5},
	year = {2024},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2023JB028525},
	pages = {e2023JB028525},
	abstract = {Based on a new seismic surface wave data set, we present a model of Alaskan crustal seismic anisotropy that provides new insight into Alaska{\textquoteright}s geographically diverse deformation history. We use both Rayleigh and Love wave isotropic phase speed and Rayleigh wave azimuthal anisotropy to estimate crustal anisotropy. Unlike traditional seismic tomography, which focuses on apparent seismic anisotropy in which the symmetry axis of anisotropy is assumed to be known, we resolve the spatial variation of inherent anisotropy by inferring the depth-dependent tilt of the hexagonally symmetric elastic tensor. The amplitude of inherent anisotropy is typically stronger in the lower than the upper crust. We principally interpret the dip angle (plunge of the symmetry axis) or the tilt of the anisotropy foliation plane, which reflects the influence of vertically and/or horizontally oriented structures or deformation. The depth variation of crustal anisotropy appears in four principal motifs that partition Alaska into six distinct geographical regions, which display characteristic dip angle patterns in the upper and lower crust. By considering geological context, we discuss how each region reflects active or historical crustal deformation.},
	keywords = {Alaskan continent, crustal deformation, seismic anisotropy, seismic tomography, surface wave},
	issn = {2169-9356},
	doi = {10.1029/2023JB028525},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023JB028525},
	author = {Liu, Chuanming and Ritzwoller, Michael H.}
}
@article {liu_seismic_2024,
	title = {Seismic Azimuthal Anisotropy Beneath the Alaska Subduction Zone},
	journal = {Geophysical Research Letters},
	volume = {51},
	number = {14},
	year = {2024},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2024GL109758},
	month = {07/2024},
	pages = {e2024GL109758},
	abstract = {We estimate depth-dependent azimuthal anisotropy and shear wave velocity structure beneath the Alaska subduction zone by the inversion of a new Rayleigh wave dispersion dataset from 8 to 85 s period. We present a layered azimuthal anisotropy model from the forearc region offshore to the subduction zone onshore. In the forearc crust, we find a trench-parallel pattern in the Semidi and Kodiak segments, while a trench-oblique pattern is observed in the Shumagins segment. These fast directions agree well with the orientations of local faults. Within the subducted slab, a dichotomous pattern of anisotropy fast axes is observed along the trench, which is consistent with the orientation of fossil anisotropy generated at the mid-ocean ridges of the Pacific-Vancouver and Kula-Pacific plates that is preserved during subduction. Beneath the subducted slab, a trench-parallel pattern is observed near the trench, which may indicate the direction of mantle flow.},
	keywords = {Alaska subduction zone, aleutian subduction zone, azimuthal anisotropy, seismic anisotropy, surface wave, surface wave tomography},
	issn = {1944-8007},
	doi = {10.1029/2024GL109758},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2024GL109758},
	author = {Liu, Chuanming and Sheehan, Anne F. and Ritzwoller, Michael H.}
}
@article {liu_seismic_2024,
	title = {Seismic Azimuthal Anisotropy Within the Juan de Fuca - Gorda Plate System},
	journal = {Geophysical Research Letters},
	volume = {51},
	number = {22},
	year = {2024},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024GL111835},
	pages = {e2024GL111835},
	abstract = {Abstract We estimate seismic azimuthal anisotropy for the Juan de Fuca - Gorda plates from inversion of a new 10{\textendash}80 s period Rayleigh wave dataset, resulting in a two-layer model to 80 km depth. In the lithosphere, most anisotropy patterns reflect the kinematics of plate formation, as approximated from seafloor-age-based paleo-spreading, except for regions close to propagator wakes and near plate boundaries. In the asthenosphere, the fast propagation orientations align with convective shear as inferred from the NUVEL1A plate motion model, which is indicative of a \~{}3 Myr average, rather than with the more recent, \~{}0.8 Myr, motions inferred from MORVEL. Regional anisotropy of this young plate system thus records convection like older plates such as the Pacific. On smaller scales, anisotropy imaging provides insights into dynamics of plate generation and can further elucidate plate reorganizations and changes in boundary loading.},
	keywords = {juan de fuca plate, oceanic lithosphere, seismic aniostropy, seismic tomography, surface wave tomography},
	doi = {https://doi.org/10.1029/2024GL111835},
	author = {Liu, Chuanming and Becker, Thorsten and Wu, Mengyu and Han, Shuoshuo and Ritzwoller, Michael H.}
}
@article {li_seismic_2024,
	title = {Seismic Evidence for Crustal Magmatic Intrusion Beneath the Southern Part of the Eastern North American Margin},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {129},
	number = {5},
	year = {2024},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2023JB028143},
	month = {05/2024},
	pages = {e2023JB028143},
	abstract = {The southern portion of the eastern North American margin (SENAM) is an archetypical volcanic passive margin formed during Mesozoic rifting. How past magmatic events affect the evolution of the SENAM remains an open question of fundamental importance. To better understand this question, here we construct a high-resolution 3-D crustal velocity model from the oceanic side to the continental interior with a combination of multimodal dispersion inversion and full-waveform ambient noise tomography. Our new model reveals an oceanic-continental transitional crust over a short horizonal distance of 100{\textendash}150 km across the SENAM, with a local-scale lower-than-surrounding velocity anomaly directly beneath the transitional crust. Furthermore, the new model shows three intra-crustal higher-than-average velocity anomalies beneath the SENAM continent. We suggest that the magmatism assisted the Mesozoic rifting process to form the narrow ocean-continent transitional crust along the coastline. The underplating of magma beneath the transitional crust led to a reduction of seismic velocity of the uppermost mantle. In addition, it is probable that the emplacement of the Central Atlantic Magmatic Province caused widespread magmatic intrusions within the continental crust of the SENAM, which were later solidified into intra-crustal high-velocity plutons. Our findings provide new insights into crustal modification history at the passive margin.},
	keywords = {crustal structures, full-waveform ambient noise tomography, magmatic intrusion, multimodal dispersion inversion, the eastern North American margin},
	issn = {2169-9356},
	doi = {10.1029/2023JB028143},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023JB028143},
	author = {Li, Cong and Yu, Chunquan}
}
@article {dunn_seismic_2024,
	title = {A Seismic Tomography, Gravity, and Flexure Study of the Crust and Upper Mantle Structure Across the Hawaiian Ridge: 2. Ka{\textquoteright}ena},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {129},
	number = {2},
	year = {2024},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2023JB028118},
	month = {05/2024},
	pages = {e2023JB028118},
	abstract = {The Hawaiian Ridge, a classic intraplate volcanic chain in the Central Pacific Ocean, has long attracted researchers due to its origin, eruption patterns, and impact on lithospheric deformation. Thought to arise from pressure-release melting within a mantle plume, its mass-induced deformation of Earth{\textquoteright}s surface depends on load distribution and lithospheric properties, including elastic thickness (Te). To investigate these features, a marine geophysical campaign was carried out across the Hawaiian Ridge in 2018. Westward of the island of O{\textquoteright}ahu, a seismic tomographic image, validated by gravity data, reveals a large mass of volcanic material emplaced on the oceanic crust, flanked by an apron of volcaniclastic material filling the moat created by plate flexure. The ridge adds \~{}7 km of material to pre-existing \~{}6-km-thick oceanic crust. A high-velocity and high-density core resides within the volcanic edifice, draped by alternating lava flows and mass wasting material. Beneath the edifice, upper mantle velocities are slightly higher than that of the surrounding mantle, and there is no evidence of extensive magmatic underplating of the crust. There is \~{}3.5 km of downward deflection of the sediment-crust and crust-mantle boundaries due to flexure in response to the volcanic load. At Ka{\textquoteright}ena Ridge, the volcanic edifice{\textquoteright}s height and cross-sectional area are no more than half as large as those determined at Hawai{\textquoteright}i Island. Together, these studies confirm that volcanic loads to the west of Hawai{\textquoteright}i are largely compensated by flexure. Comparisons to the Emperor Seamount Chain confirm the Hawaiian Ridge{\textquoteright}s relatively stronger lithospheric rigidity.},
	keywords = {Hawaiian ridge, lithospheric flexure, marine gravity, plate loading, seismic tomography, volcano structure},
	issn = {2169-9356},
	doi = {10.1029/2023JB028118},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023JB028118},
	author = {Dunn, R. A. and Watts, A. B. and Xu, C. and Shillington, D. J.}
}
@article {adimah_shear-wave_2024,
	title = {Shear-wave velocity structure of the Blanco oceanic transform fault zone},
	journal = {Geophysical Journal International},
	volume = {239},
	number = {2},
	year = {2024},
	month = {11/2024},
	pages = {1287{\textendash}1312},
	abstract = {Oceanic transform faults (OTFs) facilitate hydrothermal circulation which can modify the fault zone materials and affect their rheological evolution. However, the depth extent and variability of fluid infiltration, degree of mineral alteration and their relationship with earthquake behaviour has only been characterized along a few OTFs globally. Here, we use first-overtone Rayleigh waves extracted from seismic ambient noise to estimate the shear-wave velocity structure beneath the Blanco Transform Fault Zone (BTFZ). Compared to the adjoining normal oceanic plates, relatively variable and slow velocities reduced by at least \$\textbackslashsim\$0.2{\textendash}0.4~km s-1 (\$\textbackslashsim\$4{\textendash}8 per cent) are observed from the crust down to \$\textbackslashsim\$22~km depth along some segments of the BTFZ. The crustal slow velocities can be explained by enhanced fluid-filled porosity of \$\textbackslashsim\$0.4{\textendash}10.9 per cent caused by intense fracturing associated with abundant seismicity. Slow uppermost mantle velocities are predominantly consistent with \$\textbackslashsim\$1.2{\textendash}37 per cent serpentinization and \$\textbackslashsim\$9 per cent hydration, indicating variable and deep fluid infiltration that exceeds 15~km depth. For instance, shear-wave velocities (\$\textbackslashsim\$4.3{\textendash}4.4~km s-1) in the uppermost mantle beneath the Blanco Ridge suggest extensive serpentinization (\$\textbackslashsim\$13{\textendash}25 per cent), which might explain the recently documented earthquake swarms linked with aseismic creep. In comparison, within the vicinity of the ridge-transform intersections at depths \$\textbackslashsim\$\$\textbackslashgt \$16~km, low velocities (\$\textbackslashsim\$4.1{\textendash}4.2~km s-1) that are consistent with the presence of up to \$\textbackslashsim\$1.6 per cent partial melt suggest intratransform magmatism which would contradict the long-held simple conservative strike-slip characterization of OTFs.},
	issn = {1365-246X},
	doi = {10.1093/gji/ggae318},
	url = {https://doi.org/10.1093/gji/ggae318},
	author = {Adimah, Nicholas Irabor and Tan, Yen Joe and Russell, Joshua Berryman}
}
@article {acquisto_structural_2024,
	title = {Structural Controls on Megathrust Slip Behavior Inferred From a 3D, Crustal-Scale, P-Wave Velocity Model of the Alaska Peninsula Subduction Zone},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {129},
	number = {11},
	year = {2024},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024JB029632},
	pages = {e2024JB029632},
	abstract = {Abstract In subduction zones, along-strike and downdip variations in megathrust slip behavior are linked to changes in properties of the subducting and overriding plates. Although marine geophysical methods provide insights into subduction zone structures, most surveys consist of sparse 2D profiles, limiting our understanding of first-order controls. Here, we use active-source seismic data to derive a 3D crustal-scale P-wave velocity model of the Alaska Peninsula subduction zone that encompasses both plates and spans the Semidi segment and SW Kodiak asperity. Our results reveal modest variations within the incoming plate, attributed to a series of fracture zones, seamounts and their associated basement swell, collectively contributing to plate hydration. Basement swell appears to modulate the distribution and type of sediment entering the trench, likely impacting observed variations in slip behavior. The overriding plate exhibits significant heterogeneity. The updip limit and width of the dynamic backstop are similar between the SW Kodiak asperity and eastern Semidi segment, but differ significantly from the Western Semidi segment. These distinctions likely account for differences in earthquake rupture patterns and interseismic coupling among these segments. Additionally, high-velocities in the mid-lower forearc crust coincide with the location of megathrust slip during the Mw 8.2 2021 Chignik event. We interpret these velocities as intracrustal intrusions that contributed to the deep rupture of the 2021 event. Our findings suggest that the contrasting structural and material properties of both the incoming and overriding plates influence the spatially complex and semi-persistent segmentation of the megathrust offshore the Alaska Peninsula.},
	doi = {https://doi.org/10.1029/2024JB029632},
	author = {Acquisto, T. and B{\'e}cel, A. and Canales, J. P. and Beauc{\'e}, E.}
}
@article {carbotte_subducting_2024,
	title = {Subducting plate structure and megathrust morphology from deep seismic imaging linked to earthquake rupture segmentation at Cascadia},
	journal = {Science Advances},
	volume = {10},
	number = {23},
	year = {2024},
	note = {_eprint: https://www.science.org/doi/pdf/10.1126/sciadv.adl3198},
	pages = {eadl3198},
	abstract = {The origin of rupture segmentation along subduction zone megathrusts and linkages to the structural evolution of the subduction zone are poorly understood. Here, regional-scale seismic imaging of the Cascadia margin is used to characterize the megathrust spanning 900 km from Vancouver Island to the California border, across the seismogenic zone to a few tens of kilometers from the coast. Discrete domains in lower plate geometry and sediment underthrusting are identified, not evident in prior regional plate models, which align with changes in lithology and structure of the upper plate and interpreted paleo-rupture patches. Strike-slip faults in the lower plate associated with oblique subduction mark boundaries between regions of distinct lower plate geometry. Their formation may be linked to changes in upper plate structure across long-lived upper plate faults. The Juan de Fuca plate is fragmenting within the seismogenic zone at Cascadia as the young plate bends beneath the heterogeneous upper plate resulting in structural domains that coincide with paleo-rupture segmentation. A fragmented lower plate in the Cascadia seismogenic zone bounds structural domains linked to paleo-rupture segmentation.},
	doi = {10.1126/sciadv.adl3198},
	author = {Carbotte, Suzanne M. and Boston, Brian and Han, Shuoshuo and Shuck, Brandon and Beeson, Jeffrey and Canales, J. Pablo and Tobin, Harold and Miller, Nathan and Nedimovic, Mladen and Tr{\'e}hu, Anne and Lee, Michelle and Lucas, Madelaine and Jian, Hanchao and Jiang, Danqi and Moser, Liam and Anderson, Chris and Judd, Darren and Fernandez, Jaime and Campbell, Chuck and Goswami, Antara and Gahlawat, Rajendra}
}
@article {priestley_thermal_2024,
	title = {The thermal and anisotropic structure of the top 300 km of the mantle},
	journal = {Earth and Planetary Science Letters},
	volume = {626},
	year = {2024},
	month = {01/2024},
	pages = {118525},
	abstract = {From our analyses of fundamental and higher-mode surface waves from \~{}1.2{\texttimes}107 seismograms, we constructed tomographic models of Vsv and Vsh. At depths shallower than 300 km, models of the temperature of cooling oceanic lithosphere, pressure and temperature estimates from garnet peridotite nodules, and the estimated average potential temperature of the convecting upper mantle from the thickness of the oceanic crust are combined with laboratory measurements of shear modulus and attenuation to parameterize the dependence of Vsv on temperature and pressure. The resulting parameters agree with those from independent laboratory measurements, which extend over a range of nine orders of magnitude of the dimensionless period. The fitting parameters were then used to produce global estimates of the temperature at depths shallower than 300 km and of the lithospheric thickness. The resulting map is similar to those of previous studies, though the use of such a large number of seismograms has considerably improved the resolution. Extensive regions of the continents are underlain by lithosphere whose thickness is less than that of old oceanic lithosphere. In contrast, the lithospheric thickness beneath most cratons is between 180 and 220 km. Where rifted continental margins formed when Pangea fragmented and cut across the cratonic lithosphere, the present continental margins coincide with the margins of the cratons.},
	keywords = {cratons, lithospheric thickness, ridge axes, shear wave tomography, upper mantle temperatures},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2023.118525},
	url = {https://www.sciencedirect.com/science/article/pii/S0012821X2300537X},
	author = {Priestley, Keith and Ho, Tak and Takei, Yasuko and McKenzie, Dan}
}
@article {sahoo_tidal_2024,
	title = {Tidal triggering of seismic swarm associated with hydrothermal circulation at Blanco ridge transform fault zone, Northeast Pacific},
	journal = {Physics of the Earth and Planetary Interiors},
	volume = {356},
	year = {2024},
	month = {11/2024},
	pages = {107259},
	abstract = {Seismicity associated with hydrothermal systems (e.g., submarine volcanoes, mid-oceanic ridges, oceanic transform faults, etc.) share a complex relationship with the tidal forcing and induced fluid flow process under different tectonic settings. The hydrothermal circulation drives the deformation at the brittle-ductile transition zone within a permeable brittle crust. Although the tidal loading amplitudes are too small to generate a brittle deformation, the incremental pressure exerted by the tidal loading can modulate the flow of hydrothermal fluid circulation and trigger the critically stressed faults or fracture zones. We present a compelling case of tidal modulation in seismicity along the Blanco Ridge Transform Fault Zone (BRTFZ), in the northeast Pacific. The strong diurnal and fortnightly periodicity has been observed in the deeper seismic swarm (7{\textendash}15~km), whereas the shallow seismic swarm (0{\textendash}7~km) does not exhibit any such tidal periodicity. The dominance of diurnal and fortnightly periodicity in the deeper seismic swarm is explained by the high amplitude tidal cycles providing additional stress on the fluid circulation at the crust-mantle boundary. Moreover, our robust statistical correlation of seismicity with tidal stress and resonance destabilization model under rate-and-state friction formalism suggests that the fault segments are conditionally unstable and more sensitive to periodic tidal stress perturbation.},
	keywords = {Hydrothermal fluid, Ocean transform fault, Resonance destabilization, Seismic swarm, Tidal periodicity},
	issn = {0031-9201},
	doi = {10.1016/j.pepi.2024.107259},
	url = {https://www.sciencedirect.com/science/article/pii/S0031920124001171},
	author = {Sahoo, Sambit and Senapati, Batakrushna and Panda, Dibyashakti and Jin, Shuanggen and Kundu, Bhaskar}
}
@article {zhang_water-wave-induced_2024,
	title = {Water-Wave-Induced OBS Noise: Theories, Observations, and Potential Applications},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {129},
	number = {4},
	year = {2024},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2023JB027787},
	month = {04/2024},
	pages = {e2023JB027787},
	abstract = {The horizontal records of ocean-bottom seismometers (OBS) are usually highly noisy, generally due to ocean-bottom currents tilting the instrument, which greatly limits their practical usage in ocean-bottom seismology. In shallow water, water waves with energy concentration around 0.07 Hz induce additional noise on OBSs. Such noise is not well understood. In this article, we propose a noise model to explain the horizontal noise around 0.07 Hz. The noise model consists of three types of noise, that is, water-wave-induced noise, current noise with a relatively constant orientation, and background random noise. The wave-induced horizontal acceleration is theoretically shown to be proportional to the time derivative of ocean-bottom pressure. We validate the noise model and related theories using realistic observations. Results are potentially applicable to determine the propagation direction of water waves nearshore, and also provide constraints on the underlying Earth structure. The results can also be applied to the removal of wave-induced noise, achieving a typical maximum improvement in the signal-to-noise ratio of 10{\textendash}20 dB for time periods with strong wave noise.},
	keywords = {infragravity waves, OBS noise, ocean-bottom pressure, tilt noise},
	issn = {2169-9356},
	doi = {10.1029/2023JB027787},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023JB027787},
	author = {Zhang, Chun and An, Chao}
}
@article {lindner_bayesian_2023,
	title = {Bayesian regional moment tensor from ocean bottom seismograms recorded in the Lesser Antilles: implications for regional stress field},
	journal = {Geophysical Journal International},
	volume = {233},
	number = {2},
	year = {2023},
	month = {12/2022},
	pages = {1036{\textendash}1054},
	abstract = {Seismic activity in the Lesser Antilles (LA) is characterized by strong regional variability along the arc reflecting the complex subduction setting and history. Although routine seismicity monitoring can rely on an increasing number of island stations, the island-arc setting means that high-resolution monitoring and detailed studies of fault structures require a network of ocean bottom seismometers (OBS). As part of the 2016{\textendash}2017 Volatile recycling at the Lesser Antilles arc (VoiLA) project, we deployed 34 OBS stations in the forearc and backarc. During the deployment time, 381 events were recorded within the subduction zone. In this paper, we perform full-waveform regional moment tensor (RMT) inversions, to gain insight into the stress distribution along the arc and at depth. We developed a novel inversion approach, AmΦB{\textemdash}{\textquoteleft}Amphibious Bayesian{\textquoteright}, taking into account uncertainties associated with OBS deployments. Particularly, the orientation of horizontal components (alignment uncertainty) and the high noise level on them due to ocean microseisms are accounted for using AmΦB. The inversion is conducted using a direct, uniform importance sampling of the fault parameters within a multidimensional tree structure: the uniXtree-sampling algorithm. We show that the alignment of the horizontal OBS components, particularly in high noise level marine environments, influences the obtained source mechanism when using standard least-squares (L2) RMT inversion schemes, resulting in systematic errors in the recovered focal mechanisms including high artificial compensated linear vector dipole (CLVD) contributions. Our Bayesian formulation in AmΦB reduces these CLVD components by nearly 60~per~cent and the aberration of the focal geometry as measured by the Kagan angle by around 40~per~cent relative to a standard L2 inversion. Subsequently, we use AmΦB-RMT to obtain 45 (Mw \&gt; 3.8) regional MT solutions, out of which 39 are new to any existing database. Combining our new results with existing solutions, we subsequently analyse a total of 151 solutions in a focal mechanism classification (FMC) diagram and map them to the regional tectonic setting. We also use our newly compiled RMT database to perform stress tensor inversions along the LA subduction zone. On the plate interface, we observe the typical compressional stress regime of a subduction zone and find evidence for upper-plate strike slip and normal fault behaviour in the north that becomes a near arc-perpendicular extensional stress regime towards the south. A dominant slab perpendicular extensional stress regime is found in the slab at 100{\textendash}200~km beneath the central part of the arc. We interpret this stress condition to be a result of slab pull varying along the arc due to partial slab detachment along previously hypothesized lateral slab tear near Grenada, at the southern end of the LA arc, leading to reactivation of pre-existing structures around the subducted Proto-Caribbean ridge.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggac494},
	url = {https://doi.org/10.1093/gji/ggac494},
	author = {Lindner, Mike and Rietbrock, Andreas and Bie, Lidong and Goes, Saskia and Collier, Jenny and Rychert, Catherine and Harmon, Nicholas and Hicks, Stephen P and Henstock, Tim and the VoiLA working group}
}
@article {morton_cascadia_2023,
	title = {Cascadia Subduction Zone Fault Heterogeneities From Newly Detected Small Magnitude Earthquakes},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {128},
	number = {6},
	year = {2023},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2023JB026607},
	month = {05/2023},
	pages = {e2023JB026607},
	abstract = {The Cascadia subduction zone (CSZ) is known to host M9 megathrust ruptures; however, no such event has occurred in historical observation. The distribution and characteristics of small- to moderate-sized earthquakes can be used to determine the behavior of the megathrust fault but are notably absent offshore the CSZ due to the distance from onshore seismometers. We use automated subspace detection coupled with an onshore-offshore seismic deployment to find small-magnitude earthquakes in the offshore seismogenic zone and analyze their locations in the context of interseismic locking and seismogenic zone extent. We detected and located 5,282 earthquakes, 4,096 of which had been previously undetected. We find that the downdip extent of the seismogenic zone as defined by interplate seismicity agrees with the 20\% locking contour of the Schmalzle et al. (2014, https://doi.org/10.1002/2013GC005172) geodetic model and extends deeper than predicted by previous thermal models. We cannot determine the updip extent of the seismogenic zone; this may be due to a lack of templates for detection in the updip source area, stress shadows updip of asperity loading, and/or strong locking to the trench. We present a map of possible asperities determined by the small earthquakes in this study. Our asperity locations and extents show some, but not complete, agreement with the asperities modeled from the 1700 M9 rupture and geodetic locking models, and good agreement with the paleo-rupture extents determined from offshore turbidites and forearc basin-based asperity estimates. This highlights the need of continued offshore observations over time, and to elucidate fine-scale variation in locking.},
	issn = {2169-9356},
	doi = {10.1029/2023JB026607},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023JB026607},
	author = {Morton, Emily A. and Bilek, Susan L. and Rowe, Charlotte A.}
}
@article {canales_casie21-obs_2023,
	title = {CASIE21-OBS: An Open-Access, OBS Controlled-Source Seismic Data Set for Investigating the Structure and Properties of the Cascadia Accretionary Wedge and the Downgoing Explorer-Juan de Fuca-Gorda Plate System},
	journal = {Seismological Research Letters},
	volume = {94},
	year = {2023},
	note = {Publisher: Seismological Society of America (SSA)},
	month = {07/2023},
	pages = {2093{\textendash}2109},
	abstract = {Geological processes at subduction zones and their associated geohazards (e.g., megathrust earthquakes, submarine landslides, tsunamis, and arc volcanism) are, to a large extent, controlled by the structure, physical properties and fluid content of the subducting plate, the accreted sediments, and the overriding plate. In these settings, modern seismic modeling and imaging techniques based on controlled-source, multicomponent ocean-bottom seismometer (OBS) data are some of the best tools available for determining the subseafloor elastic properties, which can be linked to the aforementioned properties. Here, we present CASIE21-OBS, a controlled-source marine wide-angle OBS data set recently collected across the Cascadia convergent margin as part of the larger CAscadia Seismic Imaging Experiment 2021 (CASIE21). The main component of CASIE21 is a long-offset multichannel seismic (MCS) survey of the Cascadia margin conducted in June{\textendash}July 2021 onboard R/V M.G. Langseth (cruise MGL2104) aiming to characterize the incoming plate, the plate interface geometry and properties, and the overlying sediment stratigraphy and physical properties. CASIE21-OBS was conducted during R/V M.G. Langseth cruise MGL2103 (May 2021) and R/V Oceanus cruise OC2106A (June{\textendash}July 2021). It consisted of 63 short-period four-component OBSs deployed at a total 120 stations along 10 across-trench profiles extending from \~{}50 km seaward of the deformation front to the continental shelf, and from offshore northern Vancouver Island to offshore southern Oregon. The OBSs recorded the airgun signals of the CASIE21-MCS survey as well as natural seismicity occurring during the deployment period (24 May 2021 19:00 UTC{\textendash}9 July 2021 09:00 UTC). The OBS data are archived and available at the Incorporated Research Institutions for Seismology Data Management Center under network code YR_2021 for continuous time series (miniSEED) and identifier 21-008 for assembled data set (SEG-Y).},
	keywords = {3706 Geophysics},
	issn = {0895-0695},
	doi = {10.1785/0220230010},
	author = {Canales, Juan Pablo and Miller, Nathaniel C. and Baldwin, Wayne and Carbotte, Suzanne M. and Han, Shuoshuo and Boston, Brian and Jian, Hanchao and Collins, John and Lizarralde, Dan}
}
@article {mark_constraints_2023,
	title = {Constraints on Bend-Faulting and Mantle Hydration at the Marianas Trench From Seismic Anisotropy},
	journal = {Geophysical Research Letters},
	volume = {50},
	number = {10},
	year = {2023},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2023GL103331},
	month = {05/2023},
	pages = {e2023GL103331},
	abstract = {Subduction zones are a key link between the surface water cycle and the solid Earth, as the incoming plate carries pore water and hydrous minerals into the subsurface. However, water fluxes from surface to subsurface reservoirs over geologic time are highly uncertain because the volume of water carried in hydrous minerals in the slab mantle is poorly constrained. Estimates of slab mantle hydration based on seismic tomography assume bulk serpentinization, representing an upper bound on water volume. We measure azimuthal seismic anisotropy near the Marianas Trench, use spatial variations in anisotropy to constrain the extent and geometry of bend-related faulting, and place a lower bound on slab mantle water content for the case where serpentinization is confined within fault zones. The seismic observations can be explained by a minimum of \~{}0.85 wt\% water in the slab mantle, compared to the upper bound of \~{}2 wt\% obtained from tomography.},
	keywords = {anisotropy, Marianas Trench, serpentinization, solid-Earth water cycle, subduction},
	issn = {1944-8007},
	doi = {10.1029/2023GL103331},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023GL103331},
	author = {Mark, Hannah F. and Lizarralde, Daniel and Wiens, Douglas A.}
}
@article {xu_constraints_2023,
	title = {Constraints on the structure of the oceanic crust of the Tamu Massif by teleseismic P-wave coda autocorrelation},
	journal = {Frontiers in Earth Science},
	volume = {11},
	year = {2023},
	abstract = {The Tamu Massif, considered the biggest single volcano on Earth, was formed by the accumulation of enormous amounts of magma erupting to the surface. It is the largest and oldest seamount in Shatsky Rise, which is the third largest oceanic plateau on Earth. However, the formation mechanism of Tamu Massif is still controversial because evidence point to different formation hypotheses. In this paper, we applied the P-wave coda autocorrelation method and used the hydrophone waveform data acquired by the ocean bottom seismometer (OBS) deployed on Tamu Massif to constrain the oceanic crust, and these results provide new finding on the structure of the oceanic crust for Tamu Massif. We hope it can provide some implications to research the formation mechanism of Tamu Massif. These results show that some stations in Tamu Massif received reflection signals from shallower depths that are nearly parallel to the seafloor. We infer that in the shallow oceanic crust, there is a layer composed of alternating eruptions of dense, higher velocity massive lava and sparse, lower velocity pillow lava flows, which have less density and lower velocity compared to the lower oceanic crust, with a strong acoustic impedance contrasts between them and thus able to generate a reflection signal, which is observed in our autocorrelation results.},
	issn = {2296-6463},
	url = {https://www.frontiersin.org/articles/10.3389/feart.2023.1218576},
	author = {Xu, Fucong and Lu, Shaoping and Cai, Chen and Chen, Han and Dong, Shaozhe}
}
@article {trehu_deformation_2023,
	title = {Deformation of the Juan de Fuca Plate Beneath the Central Cascadia Continental Margin (44{\textdegree}-45{\textdegree}N) in Response to an Upper Plate Load},
	journal = {Earth Science, Systems and Society},
	volume = {3},
	year = {2023},
	note = {Publisher: Frontiers},
	month = {11/2023},
	pages = {10085},
	abstract = {A 3D crustal model for the central Cascadia continental shelf and Coast Range between 44{\textdegree}N and 45{\textdegree}N shows that the crystalline crust of the forearc wedge beneath the coastline is characterized by a NW-trending, vertical slab of high-velocity rock interpreted to represent the dike complex that fed the Yachats basaltsBasalt, which werewas intruded into the forearc approximately 3637 million years ago. A spatial correlation is observed between downward deflection of the crust of the subducting Juan de Fuca plate, inferred from inversion of PmP arrivals to image the Moho surface, and the high velocity (and consequently high density) dike complex.anomaly underlying the Yachats Basalt. Apparent subsequent rebound of the subducting plate at greater depth suggests a primarily elastic response of the subducting plate to this load. Calculations for a range of plausible values for the magnitude of the load and the width and depth of the depression indicate that that the effective elastic thickness of the subducted Juan de Fuca plate is \textasciitilde2-<6 km. Although our simple analytical models do not include partial support of the load of the slab by the adjacent upper plate crust or time dependence to account for the motion of the slab beneath the load, incorporation of those effects should decrease rather than increase the apparent strength of the subducted plate. We conclude that the subducted Juan de Fuca plate beneath the central Oregon margin is elastically thin and has the potential to store elastic strain energy before rupturing. Our model of a well-defined, focused and static upper plate load that locally deforms the subducted plate within the nominally seismogenic or transitional part of the Cascadia plate boundary may be unique in providing a relatively straightforward scenario for estimating the mechanical properties of the subducted Juan de Fuca plate. We extrapolate from these results to speculate that elastic deformation of the subducting plate may contribute to the low level of seismicity throughout much of the Cascadia forearc in inter-seismic period between great earthquakes but note that our local results do not preclude faulting or elasto-plastic deformation of a thin and weak plate as it subducts.},
	issn = {2634-730X},
	doi = {10.3389/esss.2023.10085},
	url = {https://www.escubed.org/articles/10.3389/esss.2023.10085/full},
	author = {Tr{\'e}hu, Anne M. and Davenport, Kathy and Kenyon, Christopher B. and Carbotte, Suzanne M. and N{\'a}b{\v e}lek, John L. and Toomey, Douglas R. and Wilcock, William S. D.}
}
@article {brandl_discontinuous_2023,
	title = {Discontinuous Igneous Addition Along the Eastern North American Margin Beneath the East Coast Magnetic Anomaly},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {128},
	number = {8},
	year = {2023},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2023JB026459},
	month = {08/2023},
	pages = {e2023JB026459},
	abstract = {Detailed models of crustal structure at volcanic passive margins offer insight into the role of magmatism and the distribution of igneous addition during continental rifting. The Eastern North American Margin (ENAM) is a volcanic passive margin that formed during the breakup of Pangea \~{}200 Myr ago. The offshore, margin-parallel East Coast Magnetic Anomaly (ECMA) is thought to mark the locus of syn-rift magmatism. Previous widely spaced margin-perpendicular studies seismically imaged igneous addition as seaward dipping reflectors (SDRs) and high velocity lower crust (HVLC; >7.2 km/s) beneath the ECMA. Along-strike imaging is necessary to more accurately determine the distribution and volume of igneous addition during continental breakup. We use wide-angle, marine active-source seismic data from the 2014{\textendash}2015 ENAM Community Seismic Experiment to determine crustal structure beneath a \~{}370-km-long section of the ECMA. P-wave velocity models based on data from short-period ocean bottom seismometers reveal a \~{}21-km-thick crust with laterally variable lower crust velocities ranging from 6.9 to 7.5 km/s. Sections with HVLC (>7.2 km/s) alternate with two \~{}30-km-wide areas where the average velocities are less than 7.0 km/s. This variable structure indicates that HVLC is discontinuous along the margin, reflecting variable amounts of intrusion along-strike. Our results suggest that magmatism during rifting was segmented. The HVLC discontinuities roughly align with locations of Mid-Atlantic Ridge fracture zones, which may suggest that rift segmentation influenced later segmentation of the Mid-Atlantic Ridge.},
	keywords = {active source tomography, continental rifting, passive margin, seismic refraction, traveltime tomography},
	issn = {2169-9356},
	doi = {10.1029/2023JB026459},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023JB026459},
	author = {Brandl, Collin C. and Worthington, Lindsay L. and Magnani, M. Beatrice and Shillington, Donna J. and Luckie, Thomas W.}
}
@article {cheng_efficient_2023,
	title = {An Efficient Transfer Learning-Based OBS Seismic Phase Picker (OBSPD) Trained on Cascadia Subduction Zone Earthquake Dataset},
	journal = {Seismological Research Letters},
	volume = {95},
	number = {2A},
	year = {2023},
	month = {11/2024},
	pages = {834{\textendash}847},
	abstract = {Earthquake monitoring and many seismological studies depend on seismic phase arrivals. Thus, detecting seismic events and picking the phase arrival times are fundamentally important. In the recent years, seismic phase picking models based on deep learning approaches have been widely developed. These deep learning models can achieve better performances than traditional phase picking methods and improve the quality of phase picking for land-based earthquake monitoring. However, these models might not perform well on data from ocean-bottom seismometers (OBSs), because they are trained exclusively using onshore seismic data and have limited out-of-distribution generalization ability. Nevertheless, there are insufficient labeled OBS phase arrivals dataset to train a deep learning model from scratch. In this study, we developed an automatic phase detection model for OBS data (OBS phase detection [OBSPD]) using the transfer learning approach based on an existing U-GPD model with pretrained weights from a generalized phase detection model feature extraction system. We developed OBSPD with a limited amount of training data (2784 three-component event waveforms) from the Cascadia subduction zone (CSZ) OBS deployments. Our results show that transfer learning can achieve lower model loss with less overfitting compared to when training a model from scratch. Our new OBSPD model outperforms four existing deep learning pickers in terms of phase detection accuracy with smaller arrival time residuals on a test OBS dataset at CSZ, especially for P phases.},
	issn = {0895-0695},
	doi = {10.1785/0220230161},
	url = {https://doi.org/10.1785/0220230161},
	author = {Cheng, Zhangbao and Tan, Yen Joe and Zhang, Fan and Zhou, Pengcheng and Lin, Jian and Tian, Jinyu and Zhang, Xubo and Zha, Caicai}
}
@article {banerjee_hydrovolcanic_2023,
	title = {Hydrovolcanic Explosions at the Lava Ocean Entry of the 2018 Kilauea Eruption Recorded by Ocean-Bottom Seismometers},
	journal = {Seismological Research Letters},
	year = {2023},
	month = {mar},
	abstract = {From the beginning of May 2018, the Kilauea Volcano on the island of Hawaii experienced its largest eruption in 200~yr followed by a period of unrest for months. Because hot molten lava entered the ocean from the ocean-entry point near the lower East Rift Zone, the lava{\textendash}water interaction led to explosions. Some explosions were near the water surface and ejected fragments of lava, also known as lava bombs. In the early morning on 16 July 2018, one of those lava bombs, which was almost the size of a basketball, hit a sightseeing boat and injured 23 people. In this study, we analyzed the hydrophone data recorded from July to mid-September by ocean-bottom seismometers (OBSs) deployed offshore near the ocean entry point to identify and locate the hydroacoustic signals of the lava{\textendash}water explosions. Acoustic signals of hydrovolcanic explosions are characterized by a short duration (less than a few seconds) and a broad frequency range (at least up to 100~Hz). To automate event detection, a short-term average versus long-term average method was applied to the complete dataset. Approximately 4300 events were detected and located near the coastline and further used to prepare a catalog. The distribution of the lava{\textendash}water explosions is consistent with the pattern of the offshore lava delta formed during the 2018 eruption. Identifying such hydroacoustic signals recorded by OBSs may provide new avenues of research using various seismoacoustic events associated with volcanic eruptions.},
	issn = {0895-0695},
	doi = {10.1785/0220220195},
	url = {https://doi.org/10.1785/0220220195},
	author = {Banerjee, Puja and Shen, Yang}
}
@inbook {jezequel_impacts_2023,
	title = {Impacts of Substrate-Borne Vibrations from Pile Driving in a Benthic Marine Invertebrate},
	booktitle = {The Effects of Noise on Aquatic Life : Principles and Practical Considerations},
	year = {2023},
	pages = {1{\textendash}7},
	publisher = {Springer International Publishing},
	organization = {Springer International Publishing},
	chapter = {Impacts of Substrate-Borne Vibrations from Pile Driving in a Benthic Marine Invertebrate},
	address = {Cham},
	abstract = {Many anthropogenic activities in the ocean involve direct contact with the seabed. These benthic interactions can potentially be harmful to marine fauna. For example, pile driving is commonly used for coastal and offshore constructions, including wind farms that overlap with vital marine habitats. The sound from pile driving is a major pollutant of international concern, although studies on substrate-borne vibrations arising from these activities are scarce, particularly those which address impacts to key benthic invertebrates. In a field-based study, the impacts of substrate-borne vibrations from pile driving were quantified on the giant scallop (Placopecten magellanicus), an ecologically and commercially important bivalve. Behavioral responses of tagged scallops to pile driving were assessed at two spatial scales (< 10 and 50~m from the source). Pile driving induced valve closures in scallops at substrate-borne vibration levels similar to those measured hundreds of meters from wind turbine constructions. These responses could have long-term energetic consequences on scallops, rending them more vulnerable to predation. The results suggest offshore wind farm constructions have the potential to impact scallop populations.},
	keywords = {Anthropogenic sound, Bivalve, Climate change, Offshore wind farm, Pollution},
	isbn = {978-3-031-10417-6},
	doi = {10.1007/978-3-031-10417-6_72-1},
	url = {https://doi.org/10.1007/978-3-031-10417-6_72-1},
	author = {J{\'e}z{\'e}quel, Youenn and Cones, Seth F. and Jensen, Frants H. and Brewer, Hannah and Collins, John and Mooney, T. Aran},
	editor = {Popper, Arthur N. and Sisneros, Joseph and Hawkins, Anthony D. and Thomsen, Frank}
}
@article {liu_-situ_2023,
	title = {In-Situ Vp/Vs Reveals Fault-Zone Material Variation at the Westernmost Gofar Transform Fault, East Pacific Rise},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {128},
	number = {3},
	year = {2023},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022JB025310},
	month = {03/2023},
	pages = {e2022JB025310},
	abstract = {Ocean transform faults often generate characteristic earthquakes that repeatedly rupture the same fault patches. The westernmost Gofar transform fault quasi-periodically hosts \~{}M6 earthquakes every \~{}5 years, and microseismicity suggests that the fault is segmented into five distinct zones, including a rupture barrier zone that may have modulated the rupture of adjacent M6 earthquakes. However, the relationship between the systematic slip behavior of the Gofar fault and the fault material properties is still poorly known. Specifically, the role of pore fluids in regulating the slip of the Gofar fault is unclear. Here, we use differential travel times between nearby earthquakes to estimate the in-situ Vp/Vs of the fault-zone materials. We apply this technique to the dataset collected by an ocean-bottom-seismometer network deployed around the Gofar fault in 2008, which recorded abundant microearthquakes, and find a moderate Vp/Vs of 1.75{\textendash}1.80 in the rupture barrier zone and a low Vp/Vs of 1.61{\textendash}1.69 in the down-dip edge of the 2008 M6 rupture zone. This lateral variation in Vp/Vs may be caused by both pore fluids and chemical alteration. We also find a 5\%{\textendash}10\% increase in Vp/Vs in the barrier zone during the 9 months before the mainshock. This increase may have been caused by fluid migrations or slip transients in the barrier zone.},
	keywords = {fault-zone structure, ocean-bottom seismometer, oceanic transform fault, pore fluids, slip dilatancy, VP/VS ratio},
	issn = {2169-9356},
	doi = {10.1029/2022JB025310},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JB025310},
	author = {Liu, Tianze and Gong, Jianhua and Fan, Wenyuan and Lin, Guoqing}
}
@article {zhang_lithospheric_2023,
	title = {Lithospheric Imaging Through Reverberant Layers: Sediments, Oceans, and Glaciers},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {128},
	number = {5},
	year = {2023},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022JB026348},
	pages = {e2022JB026348},
	abstract = {The Earth, in large portions, is covered in oceans, sediments, and glaciers. High-resolution body wave imaging in such environments often suffers from severe reverberations, that is, repeating echoes of the incoming scattered wavefield trapped in the reverberant layer, making interpretation of lithospheric layering difficult. In this study, we propose a systematic data-driven approach, using autocorrelation and homomorphic analysis, to solve the twin problem of detection and elimination of reverberations without a priori knowledge of the elastic structure of the reverberant layers. We demonstrate, using synthetic experiments and data examples, that our approach can effectively identify the signature of reverberations even in cases where the recording seismic array is deployed in complex settings, for example, using data from (a) a land station sitting on Songliao basin, (b) an ocean bottom station in the fore-arc setting of the Alaska amphibious community seismic experiment, and (c) a station deployed on ice-sediment strata in the glaciers of Antarctica. The elimination of the reverberation is implemented by a frequency domain filter whose parameters are automatically tuned using seismic data alone. On glaciers where the reverberating sediment layer is sandwiched between the lithosphere and an overlying ice layer, homomorphic analysis is preferable in detecting the signature of reverberation. We expect that our technique will see wide application for high-resolution body wave imaging across a wide variety of conditions.},
	issn = {2169-9356},
	doi = {10.1029/2022JB026348},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JB026348},
	author = {Zhang, Ziqi and Olugboji, Tolulope}
}
@article {schlaphorst_local_2023,
	title = {Local seismicity around the Chain Transform Fault at the Mid-Atlantic Ridge from OBS observations},
	journal = {Geophysical Journal International},
	volume = {234},
	number = {2},
	year = {2023},
	note = {Publisher: Oxford University Press (OUP)},
	month = {08/2023},
	pages = {1111{\textendash}1124},
	abstract = {Seismicity along transform faults provides important constraints for our understanding of the factors that control earthquake ruptures. Oceanic transform faults are particularly informative due to their relatively simple structure in comparison to their continental counterparts. The seismicity of several fast-moving transform faults has been investigated by local networks, but as of today there been few studies of transform faults in slow spreading ridges. Here, we present the first local seismicity catalogue based on event data recorded by a temporary broad-band network of 39 ocean{\textendash}bottom seismometers located around the slow-moving Chain Transform Fault (CTF) along the Mid-Atlantic Ridge (MAR) from 2016 to 2017 March. We locate 972 events in the area by simultaneously inverting for a 1-D velocity model informed by the event P- and S-arrival times. We refine the depths and focal mechanisms of the larger events using deviatoric moment tensor inversion. Most of the earthquakes are located along the CTF (700) and Romanche transform fault (94) and the MAR (155); a smaller number (23) can be observed on the continuing fracture zones or in intraplate locations. The ridge events are characterized by normal faulting and most of the transform events are characterized by strike-slip faulting, but with several reverse mechanisms that are likely related to transpressional stresses in the region. CTF events range in magnitude from 1.1 to 5.6 with a magnitude of completeness around 2.3. Along the CTF we calculate a b-value of 0.81 {\textpm} 0.09. The event depths are mostly shallower than 15 km below sea level (523), but a small number of high-quality earthquakes (16) are located deeper, with some (8) located deeper than the brittle-ductile transition as predicted by the 600 {\textdegree}C-isotherm from a simple thermal model. The deeper events could be explained by the control of sea water infiltration on the brittle failure limit.},
	keywords = {3706 Geophysics},
	issn = {0956-540X},
	doi = {10.1093/gji/ggad124},
	author = {Schlaphorst, David and Rychert, Catherine A. and Harmon, Nicholas and Hicks, Stephen P. and Bogiatzis, Petros and Kendall, J-Michael and Abercrombie, Rachel E.}
}
@article {gong_machine_2023,
	title = {Machine Learning-Based New Earthquake Catalog Illuminates On-Fault and Off-Fault Seismicity Patterns at the Discovery Transform Fault, East Pacific Rise},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {24},
	number = {9},
	year = {2023},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2023GC011043},
	pages = {e2023GC011043},
	abstract = {Oceanic transform faults connect spreading centers and are imprinted with previous tectonic events. However, their tectonic interactions are not well understood due to limited observations. The Discovery transform fault system at 4{\textdegree}S, East Pacific Rise (EPR), represents a young transform system, offering a unique opportunity to study the interplay between faulting and other tectonic events at an early phases of an oceanic transform system. Discovery regularly hosts M5{\textendash}6 characteristic earthquakes, and the seafloor north of Discovery includes a 35 km-long rift zone that records a complex history of rifting, faulting and volcanism, suggesting that the transform faults likely interact with regional tectonic activity. We apply a machine-learning enabled workflow to locate 21,391 earthquakes recorded during a 1-year ocean bottom seismometer experiment in 2008. Our results indicate that seismicity on the western Discovery fault is separated into seven patches with distinct aseismic and seismic slip modes. Additionally, we observe a patch of off-fault seismicity near where seafloor abyssal hills intersect the rift zone. This seismicity may have been caused by varying opening rates as spreading rate decreases from north to south in the rift zone. Our findings suggest that the Discovery system is still evolving, and that system equilibrium has not been reached between rifting and faulting. These results reflect the complex yet rarely observed interactions between fault slip, plate rotation, and rifting which are likely ubiquitous at oceanic transform systems.},
	keywords = {fault segmentation, microseismicity, oceanic transform fault, rifting},
	issn = {1525-2027},
	doi = {10.1029/2023GC011043},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023GC011043},
	author = {Gong, Jianhua and Fan, Wenyuan and Parnell-Turner, Ross}
}
@article {boyce_new_2023,
	title = {A new P-wave Tomographic Model (CAP22) for North America: Implications for the Subduction and Cratonic Metasomatic Modification History of Western Canada and Alaska},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {128},
	number = {3},
	year = {2023},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022JB025745},
	pages = {e2022JB025745},
	abstract = {Our understanding of the present-day state and evolution of the Canadian and Alaskan mantle is hindered by a lack of absolute P-wavespeed constraints that provide complementary sensitivity to composition in conjunction with existing S-wavespeed models. Consequently, cratonic modification, orogenic history of western North America and complexities within the Alaskan Proto-Pacific subduction system remain enigmatic. One challenge concerns the difficulties in extracting absolute arrival-time measurements from often-noisy data recorded by temporary seismograph networks required to fill gaps in continental and global databases. Using the Absolute Arrival-time Recovery Method (AARM), we extract > 180,000 new absolute arrival-time residuals from seismograph stations across Canada and Alaska and combine these data with USArray and global arrival-time data from the contiguous US and Alaska. We develop a new absolute P-wavespeed tomographic model, CAP22, spanning North America that significantly improves resolution in Canada and Alaska over previous models. Slow wavespeeds below the Canadian Cordillera sharply abut fast wavespeeds of the continental interior at the Rocky Mountain Trench in southwest Canada. Slow wavespeeds below the Mackenzie Mountains continue farther inland in northwest Canada, indicating Proterozoic-Archean metasomatism of the Slave craton. Inherited tectonic lineaments colocated with this north-south wavespeed boundary suggest that both the crust and mantle may control Cordilleran orogenic processes. In Alaska, fast upper mantle wavespeeds below the Wrangell Volcanic Field favor a conventional subduction related mechanism for volcanism. Finally, seismic evidence for the subducted Kula and Yukon slabs indicate tectonic reconstructions of western North America may require revision.},
	keywords = {Alaskan Subduction Zone, body wave tomography, Cordilleran Orogenesis, North America, Slave Craton},
	issn = {2169-9356},
	doi = {10.1029/2022JB025745},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JB025745},
	author = {Boyce, A. and Liddell, M. V. and Pugh, S. and Brown, J. and McMurchie, E. and Parsons, A. and Est{\`e}ve, C. and Burdick, S. and Darbyshire, F. A. and Cottaar, S. and Bastow, I. D. and Schaeffer, A. J. and Audet, P. and Schutt, D. L. and Aster, R. C.}
}
@article {dai_novel_2023,
	title = {A Novel Method to Estimate Orientations of an Ocean-Bottom Seismometer Array for Accurate Measurement of Waveform Phases and Amplitudes},
	journal = {Seismological Research Letters},
	volume = {94},
	number = {4},
	year = {2023},
	pages = {1936{\textendash}1947},
	abstract = {The misorientation of three-component seismometers restricts the application of relevant seismic experiments such as ocean-bottom seismometer (OBS) arrays. Previous orientation determination relied on an assumption that the propagation azimuth of seismic waves follows the great-circle path (GCP) azimuth. This assumption may yield systematic errors in the estimated orientation, particularly when the ray paths are bent laterally due to velocity heterogeneity in the Earth. Here, we develop a new method for unbiasedly estimating the horizontal orientations of seismic sensors and apply this method to the Blanco transform fault OBS experiment. We first retrieve the orientations relative to the propagation azimuths from the recorded Rayleigh and P waveforms, and then determine the geographic north orientations by calculating the propagation azimuths via an Eikonal-equation-based phase-tracking method that theoretically accounts for the effect of ray bending. Synthetics test validates that the phase-tracking method can retrieve unbiased propagation azimuths of seismic waves. The final results derived from Rayleigh- and P-wave polarization analyses with the respective phase-tracked propagation azimuths are more consistent and the orientation errors are smaller, indicating the robustness and accuracy of this method. Comparing the orientations from our phase-tracking method to those from the GCP assumption, the deviation can reach up to 8{\textdegree} between these two techniques in the study region. Subsequently, when orientations of the synthetics modeled from three-dimensional elastic waveform simulation are deviated according to the GCP-predicted orientations, we find nonnegligible bias in the phase and amplitude measurements that could reduce the accuracy and resolution of following inversion, which indicates the significance of our phase-tracking method in accurate orientation of OBS arrays as well as inland seismic experiments.},
	issn = {0895-0695},
	doi = {10.1785/0220220363},
	url = {https://doi.org/10.1785/0220220363},
	author = {Dai, Andy and Bao, Xueyang and Sun, Yao-Chong and Shan, Hao}
}
@article {yang_optimal_2023,
	title = {Optimal stacking of noise cross-correlation functions},
	journal = {Geophysical Journal International},
	volume = {232},
	number = {3},
	year = {2023},
	month = {mar},
	pages = {1600{\textendash}1618},
	abstract = {Cross-correlations of ambient seismic noise are widely used for seismic velocity imaging, monitoring and ground motion analyses. A typical step in analysing noise cross-correlation functions (NCFs) is stacking short-term NCFs over longer time periods to increase the signal quality. Spurious NCFs could contaminate the stack, degrade its quality and limit its use. Many methods have been developed to improve the stacking of coherent waveforms, including earthquake waveforms, receiver functions and NCFs. This study systematically evaluates and compares the performance of eight stacking methods, including arithmetic mean or linear stacking, robust stacking, selective stacking, cluster stacking, phase-weighted stacking, time{\textendash}frequency phase-weighted stacking, Nth-root stacking and averaging after applying an adaptive covariance filter. Our results demonstrate that, in most cases, all methods can retrieve clear ballistic or first arrivals. However, they yield significant differences in preserving the phase and amplitude information. This study provides a practical guide for choosing the optimal stacking method for specific research applications in ambient noise seismology. We evaluate the performance using multiple onshore and offshore seismic arrays in the Pacific Northwest region. We compare these stacking methods for NCFs calculated from raw ambient noise (referred to as Raw NCFs) and from ambient noise normalized using a one-bit clipping time normalization method (referred to as One-bit NCFs). We evaluate six metrics, including signal-to-noise ratios, phase dispersion images, convergence rate, temporal changes in the ballistic and coda waves, relative amplitude decays with distance and computational time. We show that robust stacking is the best choice for all applications (velocity tomography, monitoring and attenuation studies) using Raw NCFs. For applications using One-bit NCFs, all methods but phase-weighted and Nth-root stacking are good choices for seismic velocity tomography. Linear, robust and selective stacking methods are all equally appropriate choices when using One-bit NCFs for monitoring applications. For applications relying on accurate relative amplitudes, the linear, robust, selective and cluster stacking methods all perform well with One-bit NCFs. The evaluations in this study can be generalized to a broad range of time-series analysis that utilizes data coherence to perform ensemble stacking. Another contribution of this study is the accompanying open-source software package, StackMaster, which can be used for general purposes of time-series stacking.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggac410},
	url = {https://doi.org/10.1093/gji/ggac410},
	author = {Yang, Xiaotao and Bryan, Jared and Okubo, Kurama and Jiang, Chengxin and Clements, Timothy and Denolle, Marine A}
}
@article {webb_optimizing_2023,
	title = {Optimizing Ocean Bottom Seismometers for Shallow Water Using Shielding and Horizontal Pressure Gradient Data},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {128},
	number = {8},
	year = {2023},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2023JB026356},
	pages = {e2023JB026356},
	abstract = {We show large {\textquotedblleft}shields{\textquotedblright} can significantly reduce horizontal component noise levels for ocean bottom seismometers by shielding the seismic sensors from shaking due to ocean currents. However, at short period (<1 s) some noise from vibration or rocking of the shield under current can partly couple through the ground causing peaks in the noise spectra. Deformation of the seafloor under ocean wave loading ({\textquotedblleft}compliance{\textquotedblright}) raises noise levels at long period (>5 s) for both vertical and horizontal components at shallow water sites. Pressure gauge data is now routinely used to predict and remove this source of noise on vertical component data. We have developed horizontal pressure gradient (HPG) gauges to measure and remove this source of noise from horizontal component data. The combination of HPG data and shielding enables low noise long period seismic observations at otherwise very noisy shallow seafloor sites.},
	keywords = {instrumentation, seafloor, seismology},
	issn = {2169-9356},
	doi = {10.1029/2023JB026356},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023JB026356},
	author = {Webb, Spahr C. and Barclay, Andrew H.}
}
@article {wu_plate_2023,
	title = {Plate Age and Uppermost Mantle Structure Across the Juan de Fuca and Gorda Plates},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {128},
	number = {8},
	year = {2023},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2023JB026494},
	pages = {e2023JB026494},
	abstract = {To test the relationship between plate age and uppermost mantle structure for the Juan de Fuca and Gorda plates, as well as the mode of lithospheric cooling, we produce a new 3D oceanic shear wave speed (VS) model. This model is constructed using a new high-quality Rayleigh wave phase speed data set across the plates and is based on a novel thermo-seismic hybrid parameterization. In the lithosphere, we find that the VS structure is primarily (68\% of study area) governed by conductive cooling. Exceptions are observed, suggesting advective heat influx along ridges and hydrothermal circulation through cracks near the subduction trench and transform faults. In the asthenosphere of the Juan de Fuca plate, no simple monotonic relationship between seismic structure and plate age exists, but instead there is a non-monotonic slow-fast-slow VS pattern from west to east. The two slow asthenospheric VS anomalies indicate the presence of partial melt beneath both the mid-ocean ridge and the subduction trench. The partial melt beneath the trench is enigmatic.},
	keywords = {asthenosphere, Juan de Fuca, Lithosphere, plate age, thermal structure, Vs model},
	issn = {2169-9356},
	doi = {10.1029/2023JB026494},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023JB026494},
	author = {Wu, Mengyu and Wang, Hongda and Zhang, Shane and Ritzwoller, Michael H.}
}
@article {farrell_relationship_2023,
	title = {The Relationship Between Wind, Waves, Bathymetry, and Microseisms in Yellowstone Lake, Yellowstone National Park},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {128},
	number = {7},
	year = {2023},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022JB025943},
	month = {06/2023},
	pages = {e2022JB025943},
	abstract = {We conducted a multidisciplinary geophysical experiment to study the relationship between wind, waves, bathymetry, and microseisms in Yellowstone Lake{\textemdash}a small, isolated body of water in which wind-driven gravity waves excite low-amplitude seismic energy at periods \~{}1.0 s with a regular daily pattern. During 25 June{\textendash}4 August 2018, we deployed 40 short-period seismometers, four meteorological stations, and two wave gauges in and around Yellowstone Lake. These instruments were complemented by seven permanent seismometers on the lake perimeter, and a contemporaneous deployment of 10 lake bottom seismometers (LBS) on the floor of the north-central portion of the lake. The daily wind cycle, with southwesterly winds rising from \~{}0 m/s in the early morning to maxima of 10{\textendash}15 m/s in the late afternoon, generated lake waves with significant heights of \~{}0.3{\textendash}0.4 m and dominant periods of 1.5{\textendash}2.5 s, which in turn generated microseisms with dominant periods of \~{}0.8{\textendash}1.2 s, in excellent agreement with the double-frequency generation mechanism. Microseism energy was strongest on the lake floor stations, followed by the island stations and those along the northeastern coast of the lake, suggesting that these sites are closest to the source region where interference between incident and shoreline-reflected waves is responsible for microseism generation. Smaller amplitude single-frequency microseism energy was observed primarily along the northeastern lake shoreline. Both types of microseism energy are sensitive to shoreline morphology and lake wave dynamics, such that long-term monitoring of lake microseisms may further our understanding of how these processes change over time.},
	issn = {2169-9356},
	doi = {10.1029/2022JB025943},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JB025943},
	author = {Farrell, Jamie and Koper, Keith D. and Sohn, Robert A.}
}
@article {dai_seismic_2023,
	title = {Seismic imaging beneath Cascadia shows shallow mantle flow patterns guide lower mantle upwellings},
	journal = {Journal of Geophysical Research: Solid Earth},
	year = {2023},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2023JB026374},
	pages = {e2023JB026374},
	abstract = {The mantle transition zone plays an important role in modulating material transport between the upper mantle and the lower mantle. Constraining this transport is essential for understanding geochemical reservoirs, hydration cycles, and the evolution of the Earth. Slabs and hotspots are assumed to be the dominant locations of transport. However, the degree of material transport in other areas is debated. We apply P-to-S receiver functions to an amphibious dataset from Cascadia to image the mantle transition zone discontinuities beneath mid-ocean ridges, a hotspot, and a subduction zone. We find a mantle transition zone thinned by 10 {\textpm} 6 km beneath the ridges and by 8 {\textpm} 4 km behind the slab, closely resembling the 660 discontinuity topography. Depressions on the 410 discontinuity are smaller, 5 {\textpm} 2 km on average, focused in the north and the south and accompanied by supra-410 discontinuity melt phases. The depressions occur away from locations of uplifted 660 discontinuity, but near slow seismic velocity anomalies imaged in the upper mantle. This suggests lower mantle upwellings occur beneath ridges and slabs but stall in the transition zone, with upper mantle convection determining upward material transport from the transition zone. Therefore, upper mantle dynamics play a larger role in determining transfer than typically assumed.},
	issn = {2169-9356},
	doi = {10.1029/2023JB026374},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023JB026374},
	author = {Dai, Yuhang and Rycherrt, Catherine A. and Harmon, Nicholas}
}
@article {macgregor_seismic_2023,
	title = {A Seismic Tomography, Gravity, and Flexure Study of the Crust and Upper Mantle Structure of the Hawaiian Ridge: 1},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {128},
	number = {12},
	year = {2023},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2023JB027218},
	month = {11/2023},
	pages = {e2023JB027218},
	abstract = {The Hawaiian Ridge has long been a focus site for studying lithospheric flexure due to intraplate volcano loading, but crucial load and flexure details remain unclear. We address this problem using wide-angle seismic refraction and reflection data acquired along a \~{}535-km-long profile that intersects the ridge between the islands of Maui and Hawai{\textquoteright}i and crosses 80{\textendash}95 Myr-old lithosphere. A tomographic image constructed using travel time data of several seismic phases reveals broad flexure of Pacific oceanic crust extending up to \~{}200{\textendash}250 km either side of the Hawaiian Ridge, and vertically up to \~{}6{\textendash}7 km. The P-wave velocity structure, verified by gravity modeling, reveals that the west flank of Hawaii is comprised of extrusive lavas overlain by volcanoclastic sediments and a carbonate platform. In contrast, the H{\={a}}na Ridge, southeast of Maui, contains a high-velocity core consistent with mafic or ultramafic intrusive rocks. Magmatic underplating along the seismic line is not evident. Reflectors at the top and bottom of the pre-existing oceanic crust suggest a \~{}4.5{\textendash}6 km crustal thickness. Simple three-dimensional flexure modeling with an elastic plate thickness, Te, of 26.7 km shows that the depths to the reflectors beneath the western flank of Hawai{\textquoteright}i can be explained by volcano loading in which Maui and the older islands in the ridge contribute \~{}43\% to the flexure and the island of Hawai{\textquoteright}i \~{}51\%. Previous studies, however, revealed a higher Te beneath the eastern flank of Hawai{\textquoteright}i suggesting that isostatic compensation may not yet be complete at the youngest end of the ridge.},
	keywords = {Hawaiian ridge, lithospheric flexure, marine gravity, plate loading, seismic tomography, volcano structure},
	issn = {2169-9356},
	doi = {10.1029/2023JB027218},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023JB027218},
	author = {MacGregor, B. G. and Dunn, R. A. and Watts, A. B. and Xu, C. and Shillington, D. J.}
}
@article {leptokaropoulos_seismicity_2023,
	title = {Seismicity Properties of the Chain Transform Fault Inferred Using Data From the PI-LAB Experiment},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {128},
	number = {3},
	year = {2023},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022JB024804},
	month = {02/2023},
	pages = {e2022JB024804},
	abstract = {Oceanic transform faults are intriguing in that they do not produce earthquakes as large as might be expected given their dimensions. We use 1-year of local seismicity (370 events above MC = 2.3) recorded on an array of ocean bottom seismometers (OBSs) and geophysical data to study the seismotectonic properties of the Chain transform, located in the equatorial Mid-Atlantic. We extend our analysis back in time by considering stronger earthquakes (MW >= 5.0) from global catalogs. We divide Chain into three areas (east, central, and west) based on historical event distribution, morphology, and multidimensional OBS seismicity cluster analysis. Seismic activity recorded by the OBS is the highest at the eastern area of Chain where there is a lozenge-shaped topographic high, a negative rMBA gravity anomaly, and only a few historical MW >= 5.5 events. OBS seismicity rates are lower in the western and central areas. However, these areas accommodate the majority of seismic moment release, as inferred from both OBS and historical data. Higher b-values are significantly correlated with lower rMBA and with shallower bathymetry, potentially related to thickened crust. Our results suggest high lateral heterogeneity along Chain. Patches with moderate to low OBS seismicity rates that occasionally host MW >= 6.0 earthquakes are interrupted by segments with abundant OBS activity but few historical events with 5.5 <= MW < 6.0. This segmentation is possibly due to variable fluid circulation and alteration, which may also change in time.},
	keywords = {fault segmentation, Mid Atlantic Ridge, OBS seismicity, oceanic transform faults, seismotectonics},
	issn = {2169-9356},
	doi = {10.1029/2022JB024804},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JB024804},
	author = {Leptokaropoulos, K. and Rychert, C. A. and Harmon, N. and Kendall, J. M.}
}
@article {ren_seismotectonics_2023,
	title = {Seismotectonics of the Blanco Transform Fault System, Northeast Pacific: Evidence for an Immature Plate Boundary},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {128},
	number = {3},
	year = {2023},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022JB026045},
	month = {03/2023},
	pages = {e2022JB026045},
	abstract = {At the Blanco transform fault system (BTFS) off Oregon, 138 local earthquakes and 84 double-couple focal mechanisms from ocean-bottom-seismometer recordings jointly discussed with bathymetric features reveal a highly segmented transform system without any prominent fracture zone traces longer than 100 km. In the west, seismicity is focused at deep troughs (i.e., the West and East Blanco, and Surveyor Depressions). In the east, the BTFS lacks a characteristic transform valley and instead developed the Blanco Ridge, which is the most seismically active feature, showing strike-slip and dip-slip faulting. Sandwiched between the two main segments of the BTFS is the Cascadia Depression, representing a short intra-transform spreading segment. Seismic slip vectors reveal that stresses at the eastern BTFS are roughly in line with plate motion. In contrast, stresses to the west are clockwise skewed, indicating ongoing reorganization of the OTF system. As we observed no prominent fracture zones at the BTFS, plate tectonic reconstructions suggest that the BTFS developed from non-transform offsets rather than pre-existing transform faults during a series of ridge propagation events. Our observations suggest that the BTFS can be divided into two oceanic transform systems. The eastern BTFS is suggested to be a mature transform plate boundary since \~{}0.6 Ma. In contrast, the western BTFS is an immature transform system, which is still evolving to accommodate far-field stress change. The BTFS acts as a natural laboratory to yield processes governing the development of oceanic transform faults.},
	keywords = {Blanco transform fault system, local seismicity, tectonic evolution, transform plate boundary},
	issn = {2169-9356},
	doi = {10.1029/2022JB026045},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JB026045},
	author = {Ren, Yu and Lange, Dietrich and Grevemeyer, Ingo}
}
@article {fang_sequencing_2023,
	title = {Sequencing Seismic Noise Correlations for Improving Surface Wave Retrieval and Characterizing Noise Sources},
	journal = {Seismological Research Letters},
	volume = {95},
	number = {2A},
	year = {2023},
	month = {03/2024},
	pages = {848{\textendash}858},
	abstract = {Cross-correlating continuous seismic data is a commonly employed technique to extract coherent signals to image and monitor the subsurface. However, due largely to site effects and poorly characterized noise sources in oceanic environments, its application to ocean-bottom seismometer (OBS) recordings often requires additional processing. In this contribution, we propose a method to improve the quality of the retrieved surface waves from OBS data and characterize the noise sources. We first cluster the pre-stack noise cross-correlation functions (NCFs) based on a sequencing algorithm, followed by selectively stacking those consisting of coherent and stable signals that are consistent with predicted surface-wave arrival times. Synthetic tests show that the sequenced NCFs can be used to recover the spatial and temporal distribution of noise sources. Applying the method to an OBS array offshore California increases the signal-to-noise ratios of the obtained Rayleigh waves. In addition, we find that the annual temporal distribution of selected NCFs with frequencies ranging from 0.04 to 0.1~Hz is nearly homogeneous during the recording period. In contrast, many NCFs excluded for stacking are temporally clustered. This method has the potential to be applied to other OBS recordings or possibly onland deployments, thus helping to obtain high-quality surface waves and to analyze temporal noise source characteristics.},
	issn = {0895-0695},
	doi = {10.1785/0220230151},
	url = {https://doi.org/10.1785/0220230151},
	author = {Fang, Hongjian}
}
@article {262,
	title = {Slab to back-arc to arc: Fluid and melt pathways through the mantle wedge beneath the Lesser Antilles},
	journal = {Science Advances},
	volume = {9},
	year = {2023},
	month = {02/2023},
	pages = {eadd2143},
	abstract = {Volatiles expelled from subducted plates promote melting of the overlying warm mantle, feeding arc volcanism. However, debates continue over the factors controlling melt generation and transport, and how these determine the placement of volcanoes. To broaden our synoptic view of these fundamental mantle wedge processes, we image seismic attenuation beneath the Lesser Antilles arc, an end-member system that slowly subducts old, tectonized lithosphere. Punctuated anomalies with high ratios of bulk-to-shear attenuation (Qκ-1/Qμ-1 > 0.6) and VP/VS (>1.83) lie 40 km above the slab, representing expelled fluids that are retained in a cold boundary layer, transporting fluids toward the back-arc. The strongest attenuation (1000/QS ~ 20), characterizing melt in warm mantle, lies beneath the back-arc, revealing how back-arc mantle feeds arc volcanoes. Melt ponds under the upper plate and percolates toward the arc along structures from earlier back-arc spreading, demonstrating how slab dehydration, upper-plate properties, past tectonics, and resulting melt pathways collectively condition volcanism.},
	keywords = {3706 Geophysics},
	issn = {2375-2548},
	doi = {10.1126/sciadv.add2143},
	url = {https://www.science.org/doi/10.1126/sciadv.add2143},
	author = {Hicks, SP and Bie, L and Rychert, CA and Harmon, N and Goes, S and Rietbrock, A and Wei, SS and Collier, JS and Henstock, TJ and Lynch, L and Prytulak, J and Macpherson, CG and Schlaphorst, D and Wilkinson, JJ and Blundy, JD and Cooper, GF and Davy, RG and Kendall, J-M and VOILA WORKING GROUP}
}
@article {fang_smatstack_2023,
	title = {SMatStack to Enhance Noisy Teleseismic Seismic Phases: Validation and Application to Resolving Depths of Oceanic Transform Earthquakes},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {24},
	number = {11},
	year = {2023},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2023GC011109},
	month = {10/2023},
	pages = {e2023GC011109},
	abstract = {The depths of most moderate-sized oceanic earthquakes are poorly constrained because of the lack of local recording stations and noisy teleseismic recordings. This hampers our understanding of slip behaviors along oceanic faults and the mechanical properties of the oceanic lithosphere. In this study, we develop a new method to enhance the weak body-wave signals, particularly the depth phases, associated with earthquakes on oceanic transform faults using large-aperture arrays in the teleseismic range. We simulate the enhanced teleseismic signals to refine the centroid depths of moderate-sized earthquakes. We validate the new approach using synthetic waveforms and show it outperforms conventional methods when dealing with noisy signals. We obtain the depth estimates for three moderate-sized earthquakes on the Chain transform fault in the equatorial Atlantic Ocean and find two of them are consistent with a local catalog derived using oceanic bottom seismometers. Application of the new method to the past decades of teleseismic recordings of moderate-sized earthquakes on the large and slow-slipping transform faults will provide significantly improved constraints on the width of the seismogenic zone, thus advancing our understanding of the rheology of oceanic lithosphere and earthquake processes in oceanic settings and, by comparison, their more dangerous continental counterparts. The new method is not limited to oceanic transform earthquakes, but can be easily adapted to other seismological studies in which noisy but coherent signals could be revisited for better usage.},
	keywords = {array analysis, earthquake depths, oceanic transform faults, seismogenic zone},
	issn = {1525-2027},
	doi = {10.1029/2023GC011109},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023GC011109},
	author = {Fang, Hongjian and Abercrombie, Rachel E.}
}
@article {yarce_temporal_2023,
	title = {Temporal Relationship of Slow Slip Events and Microearthquake Seismicity: Insights From Earthquake Automatic Detections in the Northern Hikurangi Margin, Aotearoa New Zealand},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {24},
	number = {3},
	year = {2023},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022GC010537},
	month = {03/2023},
	pages = {e2022GC010537},
	abstract = {Slow slip events in the northern Hikurangi margin of Aotearoa New Zealand occur every 18{\textendash}24 months and last for several weeks before returning to average convergence rates of around 38 mm/yr. Along this plate boundary, the Hikurangi plateau subducts beneath the overlying Australian plate and slow slip events occur along their plate interface at depths between 2 and 15 km. To explore whether there is a temporal relationship between slow slip events and earthquake occurrence, the Regressive ESTimator automated phase arrival detection and onset estimation algorithm was applied to a data set of continuous waveform data collected by both land and ocean bottom seismometers. This detector uses an autoregressive algorithm with iterative refinement to first detect seismic events and then create a catalog of hypocenters and P and S wave arrival times. Results are compared with an available catalog of manually detected seismic events. The auto-detector was able to find more than three times the number of events detected by analysts. With our newly assembled data set of automatically detected earthquakes, we were able to determine that there was an increase in the rate of earthquake occurrence during the 2014 slow slip event.},
	keywords = {earthquake detection, Hikurangi, ocean bottom seismometers, seismicity, slow slip event, subduction},
	issn = {1525-2027},
	doi = {10.1029/2022GC010537},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022GC010537},
	author = {Yarce, Jefferson and Sheehan, Anne F. and Roecker, Steven}
}
@article {paulatto_advances_2022,
	title = {Advances in seismic imaging of magma and crystal mush},
	journal = {Frontiers in Earth Science},
	volume = {10},
	year = {2022},
	month = {10/2022},
	abstract = {Seismic imaging methods have provided detailed three-dimensional constraints on the physical properties of magmatic systems leading to invaluable insight into the storage, differentiation and dynamics of magma. These constraints have been crucial to the development of our modern understanding of magmatic systems. However, there are still outstanding knowledge gaps resulting from the challenges inherent in seismic imaging of volcanoes. These challenges stem from the complex physics of wave propagation across highly heterogeneous low-velocity anomalies associated with magma reservoirs. Ray-based seismic imaging methods such as travel-time and surface-wave tomography lead to under-recovery of such velocity anomalies and to under-estimation of melt fractions. This review aims to help the volcanologist to fully utilize the insights gained from seismic imaging and account for the resolution limits. We summarize the advantages and limitations of the most common imaging methods and propose best practices for their implementation and the quantitative interpretation of low-velocity anomalies. We constructed and analysed a database of 277 seismic imaging studies at 78 arc, hotspot and continental rift volcanoes. Each study is accompanied by information about the seismic source, part of the wavefield used, imaging method, any detected low-velocity zones, and estimated melt fraction. Thirty nine studies attempted to estimate melt fractions at 22 different volcanoes. Only five studies have found evidence of melt storage at melt fractions above the critical porosity that separates crystal mush from mobile magma. The median reported melt fraction is 13\% suggesting that magma storage is dominated by low-melt fraction crystal mush. However, due to the limits of seismic resolution, the seismological evidence does not rule out the presence of small (<10~km3) and medium-sized (<100~km3) high-melt fraction magma chambers at many of the studied volcanoes. The combination of multiple tomographic imaging methods and the wider adoption of methods that use more of the seismic wavefield than the first arriving travel-times, promise to overcome some of the limitations of seismic tomography and provide more reliable constraints on melt fractions. Wider adoption of these new methods and advances in data collection are needed to enable a revolution in imaging magma reservoirs.},
	issn = {2296-6463},
	doi = {10.3389/feart.2022.970131},
	url = {https://www.frontiersin.org/articles/10.3389/feart.2022.970131},
	author = {Paulatto, Michele and Hooft, Emilie E. E. and Chrapkiewicz, Kajetan and Heath, Benjamin and Toomey, Douglas R. and Morgan, Joanna V.}
}
@article {janiszewski_broad-band_2023,
	title = {Broad-band ocean bottom seismometer noise properties},
	journal = {Geophysical Journal International},
	volume = {233},
	number = {1},
	year = {2022},
	month = {11/2022},
	pages = {297{\textendash}315},
	abstract = {We present a new compilation and analysis of broad-band ocean bottom seismometer noise properties from 15 yr of seismic deployments. We compile a comprehensive data set of representative four-component (seismometer and pressure gauge) noise spectra and cross-spectral properties (coherence, phase and admittance) for 551 unique stations spanning 18 U.S.-led experiments. This is matched with a comprehensive compilation of metadata parameters related to instrumentation and environmental properties for each station. We systematically investigate the similarity of noise spectra by grouping them according to these metadata parameters to determine which factors are the most important in determining noise characteristics. We find evidence for improvements in similarity of noise properties when grouped across parameters, with groupings by seismometer type and deployment water depth yielding the most significant and interpretable results. Instrument design, that is the entire deployed package, also plays an important role, although it strongly covaries with seismometer and water depth. We assess the presence of traditional sources of tilt, compliance, and microseismic noise to characterize their relative role across a variety of commonly used seismic frequency bands. We find that the presence of tilt noise is primarily dependent on the type of seismometer used (covariant with a particular subset of instrument design), that compliance noise follows anticipated relationships with water depth, and that shallow, oceanic shelf environments have systematically different microseism noise properties (which are, in turn, different from instruments deployed in shallow lake environments). These observations have important implications for the viability of commonly used seismic analysis techniques. Finally, we compare spectra and coherences before and after vertical channel tilt and compliance noise removal to evaluate the efficacy and limitations of these now standard processing techniques. These findings may assist in future experiment planning and instrument development, and our newly compiled noise data set serves as a building block for more targeted future investigations by the marine seismology community.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggac450},
	url = {https://doi.org/10.1093/gji/ggac450},
	author = {Janiszewski, Helen A and Eilon, Z and Russell, J B and Brunsvik, B and Gaherty, J B and Mosher, S G and Hawley, W B and Coats, S}
}
@article {iwasaki_continuous_2022,
	title = {Continuous Tremor Activity With Stable Polarization Direction Following the 2014 Large Slow Slip Event in the Hikurangi Subduction Margin Offshore New Zealand},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {127},
	number = {2},
	year = {2022},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2021JB022161},
	month = {11/2021},
	pages = {e2021JB022161},
	abstract = {Many types of slow earthquakes have been discovered at subduction zones around the world. However, the physical process of these slow earthquakes is not well understood. To monitor offshore slow earthquakes, a marine seismic and geodetic experiment was conducted at the Hikurangi subduction margin from May 2014 to June 2015. During this experiment, a large slow slip event (Mw 6.8) occurred directly beneath the ocean bottom seismometer (OBS) network. In this study, S-wave splitting and polarization analysis methods, which have been previously used on onshore data to investigate tremor and anisotropy, are applied to continuous OBS waveform data to identify tremors that are too small to detect by the envelope cross correlation method. Continuous tremor activity with stable polarization directions is detected at the end of the 2014 slow slip event and continued for about 2 weeks. The tremors are generated around a southwest bend in the slow slip contours and at the landward edge of a subducted seamount. Our findings corroborate a previous interpretation, based on burst-type repeating earthquakes and intermittent tremor, that localized slow slip and tremor around the seamount was triggered by fluid migration following the large plate boundary slow slip event and indicate tremor occurred continuously rather than as isolated and sporadic individual events.},
	keywords = {New Zealand, polarization, S-wave splitting, Seamount, slow slip, tremor},
	issn = {2169-9356},
	doi = {10.1029/2021JB022161},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021JB022161},
	author = {Iwasaki, Yuriko and Mochizuki, Kimihiro and Ishise, Motoko and Todd, Erin K. and Schwartz, Susan Y. and Zal, Hubert and Savage, Martha K. and Henrys, Stuart and Sheehan, Anne F. and Ito, Yoshihiro and Wallace, Laura M. and Webb, Spahr C. and Yamada, Tomoaki and Shinohara, Masanao}
}
@article {dunn_dual-level_2022,
	title = {A Dual-Level Magmatic System Beneath the East Pacific Rise, 9{\textdegree}N},
	journal = {Geophysical Research Letters},
	volume = {49},
	number = {18},
	year = {2022},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022GL097732},
	month = {09/2022},
	pages = {e2022GL097732},
	abstract = {Data from three co-located wide-angle ocean-bottom seismograph experiments were used to make a new two-dimensional tomographic image of the East Pacific Rise at 9{\textdegree}N. The upper half of the crustal magmatic system has a different seismic structure than the lower half, presumably corresponding with differences in melt storage and crustal cooling. The upper region is narrow (\~{}4.5 km wide at 2{\textendash}3 km depth bsf) and estimated to contain higher melt fractions; the lower region broadens with depth and contains lower melt fractions. The shape of the system suggests steeply-dipping isotherms and relatively stronger hydrothermal circulation in the upper gabbroic section of the crust, with moderately flattening isotherms and less circulation in the lower gabbroic section.},
	keywords = {East Pacific Rise, seismic anisotropy, seismic tomography},
	issn = {1944-8007},
	doi = {10.1029/2022GL097732},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022GL097732},
	author = {Dunn, Robert A.}
}
@article {ruppert_enhanced_2022,
	title = {Enhanced Regional Earthquake Catalog with Alaska Amphibious Community Seismic Experiment Data},
	journal = {Seismological Research Letters},
	volume = {94},
	number = {1},
	year = {2022},
	pages = {522{\textendash}530},
	abstract = {The Alaska Amphibious Community Seismic Experiment (AACSE) comprised 75 ocean-bottom seismometers and 30 land stations and covered about 650~km along the segment of the subduction zone that includes Kodiak Island, the Alaska Peninsula and the Shumagin Islands between May 2018 and September 2019. This unprecedented onshore-offshore dataset provided an opportunity to compile a greatly enhanced earthquake catalog for the region by both increasing the number of detected earthquakes and improving the accuracy of their source parameters. We use all available regional and AACSE campaign seismic data to compile an earthquake catalog for the region between Kodiak and the Shumagin Islands including the Alaska Peninsula (51{\textdegree}~N{\textendash}59{\textdegree}~N, 148{\textdegree}~W{\textendash}163{\textdegree}~W). We apply the same processing and reporting standards to additional picks and events as the Alaska Earthquake Center currently uses for compilation of the authoritative regional earthquake catalog. Over 7200 events (both newly detected and previously reported) have been processed with AACSE data. We added about 30\% more events, 60\% more phase picks, lowered the magnitude of completeness by about 0.2 on average across the region, and improved location errors. All data have been published in public data archives. In addition, we test the machine-learning earthquake detection and picking algorithm EarthquakeTransformer (EQT) on the AACSE seismic dataset, comparing EQT-determined P and S picks with the new catalog. EQT is entirely trained on land data, whereas AACSE is amphibious. Overall, EQT finds 59\% of P and 63\% of S arrivals in the catalog within 300~km epicentral distance. The percent of catalog picks detected by EQT varies inversely with earthquake epicentral distance, and EQT performs particularly poorly on data from earthquakes recorded by instruments in the outer rise.},
	issn = {0895-0695},
	doi = {10.1785/0220220226},
	url = {https://doi.org/10.1785/0220220226},
	author = {Ruppert, Natalia A. and Barcheck, Grace and Abers, Geoffrey A.}
}
@article {acquisto_evidence_2022,
	title = {Evidence of Strong Upper Oceanic Crustal Hydration Outboard the Alaskan and Sumatran Subduction Zones},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {127},
	number = {10},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2022JB024751},
	pages = {e2022JB024751},
	abstract = {The hydration state of subducting oceanic crust has been proposed to influence subduction zone processes like seismic coupling at the megathrust interface and arc magmatism downdip. Plate bending in the outer rise region is thought to help rehydrate the incoming oceanic lithosphere before subduction. Although numerous seismic refraction studies provide constraints on the amount of water stored in the lower crust and uppermost mantle, little information exists about how much free water is present in the upper 1{\textendash}2 km of oceanic crust. Here, we present results from the application of advanced techniques to long-offset multi-channel seismic data acquired outboard the Alaskan and South Sumatran subduction zones. Our results show that the incoming upper crustal seismic layer, layer 2A, is significantly hydrated in both areas. Favorable conditions offshore the Alaska Peninsula promote the creation of a dense system of bending-related faults, facilitating the infiltration of fluids that increases average water estimates to \~{}3.9 wt.\% H2O in the outer rise. As the crust subducts and temperature increases, some free water may react with the host rocks to form mineral-bound water that is carried to greater depths, in agreement with elevated water contents found in arc lavas of Shumagin Gap volcanoes. Offshore Sumatra, we propose that similar layer 2A water estimates (\~{}3.2 wt.\% H2O average) and heterogeneous hydration within 2B are associated with the ongoing, slow, complex deformation occurring in the Wharton Basin and thus potentially contribute to the presence of a long-lived slow slip event recently inferred there at seismogenic depths.},
	keywords = {Alaska, hydration, subduction zone, Sumatra, upper crust},
	issn = {2169-9356},
	doi = {10.1029/2022JB024751},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JB024751},
	author = {Acquisto, Tanner and B{\'e}cel, Anne and Singh, Satish C. and Carton, H{\'e}l{\`e}ne}
}
@article {wei_improved_2022,
	title = {An Improved Earthquake Catalog During the 2018 K{\i}̄lauea Eruption From Combined Onshore and Offshore Seismic Arrays},
	journal = {Earth and Space Science},
	volume = {9},
	number = {6},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2021EA001979},
	month = {06/2022},
	pages = {e2021EA001979},
	abstract = {The Island of Hawai{\textquoteright}i was formed by repeated eruptions of basalts at an oceanic hotspot. K{\i}̄lauea, the youngest among the subaerial volcanoes of the island, erupted intensely in 2018. The eruption provided an opportunity to look into the mechanisms that operate at the volcano and associated earthquake activities, as it was recorded simultaneously, for the first time, by onshore and offshore seismometers. We used most of the publicly available seismic data during the eruption period, including temporary arrays, to build a more complete earthquake catalog during the eruption than that provided by the Hawaiian Volcano Observatory. We used a short-time-average/long-time-average method to identify potential earthquakes. The detections were associated with events and automatically picked with P-wave and S-wave arrivals, which were used to locate the events in a three-dimensional velocity model. After re-examining these earthquake events, their coda/duration magnitudes were determined. The resulting half-year catalog contains 375,736 events with one of the highest daily earthquake numbers ever reported (6,128 on 21 June 2018). A great number of events were recorded during the caldera collapses, from its beginning until its rapid ending. The catalog also contains abundant events near the Pu{\textquoteright}u{\textquoteleft}o{\textquoteleft}o vent and in the lower East Rift Zone, where an increase of seismicity in mid-July and August indicated a step-up in magma intrusion after the eruption.},
	keywords = {eruption, K{\i}̄lauea, offshore, onshore, seismicity},
	issn = {2333-5084},
	doi = {10.1029/2021EA001979},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021EA001979},
	author = {Wei, XiaoZhuo and Shen, Yang and Caplan-Auerbach, Jacqueline and Morgan, Julia K.}
}
@article {carchedi_investigating_2022,
	title = {Investigating Short-Period Lake-Generated Microseisms Using a Broadband Array of Onshore and Lake-Bottom Seismometers},
	journal = {Seismological Research Letters},
	volume = {93},
	number = {3},
	year = {2022},
	month = {02/2022},
	pages = {1585{\textendash}1600},
	abstract = {Recent analyses of ambient seismic noise proximal to large lakes identify excitations between periods of 0.5 and 5~s as lake-generated microseisms, though the mechanisms producing them remain unclear in the absence of distinct spectral peaks. We present a unique data set combining onshore and offshore seismometers to investigate the dominant parameters controlling water-to-solid-earth seismic coupling in a lacustrine environment. Using a set of broadband observations that include six lake-bottom seismometers, we compare signals collected both within and around Lake Malawi (Nyasa) in southeastern Africa, the fifth largest freshwater lake in the world. We document clear evidence for two peaks within the lake microseism band, with pervasive diurnal excitations between periods of \~{}0.6{\textendash}1.3 and \~{}1.3{\textendash}3~s. Variations in spectral behavior as a function of recording depth and proximity to both steep lake-floor slopes and the shoreline suggest that the spectral bands may correspond to single- and double-frequency generation processes, akin to primary and secondary ocean microseisms generated by the shoaling of wind-driven gravity waves along shorelines and wave interactions within the open body of water, respectively. However, both the absolute amplitudes and temporal evolution we observe in these two bands are complex and often inconsistent with traditional microseism theory. Therefore, these spectral bands may alternatively result from complex wave{\textendash}wave interaction at the lake surface within the enclosed northern end of the lake. The diurnal behavior of lake microseisms, as well as their polarizations, suggest that the wave energy is driven by a combination of seasonally varying nighttime winds funneled by lakeshore topography and waveguide effects. This work also provides a glimpse into seasonal variation in lacustrine ambient seismic noise and thus also into lake processes.},
	issn = {0895-0695},
	doi = {10.1785/0220210155},
	url = {https://doi.org/10.1785/0220210155},
	author = {Carchedi, Christopher James William and Gaherty, James B. and Webb, Spahr C. and Shillington, Donna J.}
}
@article {chrapkiewicz_magma_2022,
	title = {Magma Chamber Detected Beneath an Arc Volcano With Full-Waveform Inversion of Active-Source Seismic Data},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {23},
	number = {11},
	year = {2022},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022GC010475},
	month = {10/2022},
	pages = {e2022GC010475},
	abstract = {Arc volcanoes are underlain by complex systems of molten-rock reservoirs ranging from melt-poor mush zones to melt-rich magma chambers. Petrological and satellite data indicate that eruptible magma chambers form in the topmost few kilometres of the crust. However, very few chambers have ever been definitively located, suggesting that most are too short-lived or too small to be imaged, which has direct implications for hazard assessment and modeling of magma differentiation. Here we use a high-resolution technology based on inverting full seismic waveforms to image a small, high-melt-fraction magma chamber that was not detected with standard seismic tomography. The melt reservoir extends from \~{}2 to at least 4 km below sea level (b.s.l.) at Kolumbo{\textemdash}a submarine volcano near Santorini, Greece. The chamber coincides with the termination point of the recent earthquake swarms and may be a missing link between a deeper melt reservoir and the high-temperature hydrothermal system venting at the crater floor. The chamber poses a serious hazard as it could produce a highly explosive, tsunamigenic eruption in the near future. Our results suggest that similar reservoirs (relatively small but high-melt-fraction) may have gone undetected at other active volcanoes, challenging the existing eruption forecasts and reactive-flow models of magma differentiation.},
	keywords = {full-waveform inversion, Kolumbo volcano, magma chamber, magmatic system, Santorini volcanic field, volcano tomography},
	issn = {1525-2027},
	doi = {10.1029/2022GC010475},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022GC010475},
	author = {Chrapkiewicz, K. and Paulatto, M. and Heath, B. A. and Hooft, E. E. E. and Nomikou, P. and Papazachos, C. B. and Schmid, F. and Toomey, D. R. and Warner, M. R. and Morgan, J. V.}
}
@article {gong_microseismicity_2022,
	title = {Microseismicity Indicates Atypical Small-Scale Plate Rotation at the Quebrada Transform Fault System, East Pacific Rise},
	journal = {GEOPHYSICAL RESEARCH LETTERS},
	volume = {49},
	number = {3},
	year = {2022},
	note = {Publisher: AMER GEOPHYSICAL UNION},
	month = {01/2022},
	abstract = {Closely spaced, multi-strand ridge transform faults (RTFs) accommodate relative motions along fast spreading mid-ocean ridges. However, the relations between RTFs and plate spreading dynamics are poorly understood. The Quebrada system is one of the most unique RTF systems at the East Pacific Rise, consisting of four transform faults connected by three short intra-transform spreading centers (ITSCs). We use seven-months of ocean bottom seismograph data to study the Quebrada system, and find abundant earthquakes unevenly distributed among three active faults. We identify two deep, diffuse seismicity clouds at the inside corners of the ITSC-transform fault intersections, and one seismically active fracture zone. The observations suggest a complex regional plate-motion pattern, including possible heterogeneous rotations within the Quebrada system. Evolution of multi-strand RTFs may have resulted from a strong three-dimensional local thermal and fluid effects, while the RTFs may have also regulated regional tectonics, forming an intricate feedback system.},
	keywords = {SEGMENTATION},
	issn = {0094-8276},
	doi = {10.1029/2021GL097000},
	url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2\&SrcApp=PARTNER_APP\&SrcAuth=LinksAMR\&KeyUT=WOS:000759485200037\&DestLinkType=FullRecord\&DestApp=ALL_WOS\&UsrCustomerID=8089ad20fbb398f01a4cda689a61f0e5},
	author = {Gong, J and Fan, W and Parnell-Turner, R}
}
@conference {schmidt-aursch_noise_2022,
	title = {Noise characteristics of ocean-bottom seismometer data in the Bransfield Strait, Antarctica},
	booktitle = {EPIC348. Sitzung der AG Seismologie, M{\"u}nster, 2022-09-26-2022-09-29},
	year = {2022},
	month = {sep},
	address = {M{\"u}nster},
	abstract = {All seismological data contain not only desired source signals, but also noise. There are various natural and artificial noise sources like wind, waves, traffic, industry, etc. Data recorded by ocean-bottom seismometers (OBS) show a different content of noise than onshore data; mainly because the OBS are located directly in one of the major noise generators: the oceans. Oceanic microseisms dominate the recordings over a broad frequency band, and there are several noise sources not known onshore, e.g. marine mammals, ship traffic, marine seismic surveys and especially in the polar regions sea ice and icebergs. In the framework of the BRAVOSEIS project, eight broadband ocean-bottom seismometers were deployed for one year in the Bransfield Strait, Antarctica. The ambient noise was helpful to correct the clock drift of the data loggers by means of noise cross-correlations. High-resolution probabilistic power spectral densities and spectrograms were calculated for all stations and channels to study the noise-generating processes. An analysis of tidal signals were performed for various time series including temperature recordings. Although all OBS were located within the same basin, they differ significantly in their noise characteristics. The noise spectrum was divided into several frequency bands. Some bands show seasonal variations, others are persistent during the entire year. A few noise signatures are coherent between all OBS, this is typical for origins far away. Most noise sources occur very locally and are specific for each OBS depending on parameters like water depth or the abundance of deep water currents. Generally, the noise properties are complex and show a great variation in time and space.},
	url = {https://epic.awi.de/id/eprint/57417/},
	author = {Schmidt-Aursch, Mechita C. and Almendros, Javier and Geissler, Wolfram and Wilcock, William}
}
@article {jezequel_pile_2022,
	title = {Pile driving repeatedly impacts the giant scallop (Placopecten magellanicus)},
	journal = {Scientific Reports},
	volume = {12},
	number = {1},
	year = {2022},
	month = {09/2022},
	pages = {15380},
	abstract = {Large-scale offshore wind farms are a critical component of the worldwide climate strategy. However, their developments have been opposed by the fishing industry because of concerns regarding the impacts of pile driving vibrations during constructions on commercially important marine invertebrates, including bivalves. Using field-based daily exposure, we showed that pile driving induced repeated valve closures in different scallop life stages, with particularly stronger effects for juveniles. Scallops showed no acclimatization to repetitive pile driving across and within days, yet quickly returned to their initial behavioral baselines after vibration-cessation. While vibration sensitivity was consistent, daily pile driving did not disrupt scallop circadian rhythm, but suggests serious impacts at night when valve openings are greater. Overall, our results show distance and temporal patterns can support future mitigation strategies but also highlight concerns regarding the larger impact ranges of impending widespread offshore wind farm constructions on scallop populations.},
	keywords = {Behavioural ecology, Climate-change ecology, Ecology},
	doi = {10.1038/s41598-022-19838-6},
	url = {https://app.dimensions.ai/details/publication/pub.1150956514},
	author = {J{\'e}z{\'e}quel, Youenn and Cones, Seth and Jensen, Frants H. and Brewer, Hannah and Collins, John and Mooney, T. Aran}
}
@article {russell_rayleigh_2022,
	title = {Rayleigh Wave Attenuation and Amplification Measured at Ocean-Bottom Seismometer Arrays using Helmholtz Tomography},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {n/a},
	number = {n/a},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2022JB025174},
	month = {10/2022},
	pages = {e2022JB025174},
	abstract = {Shear attenuation provides insights into the physical and chemical state of the upper mantle. Yet, observations of attenuation are infrequent in the oceans, despite recent proliferation of arrays of ocean-bottom seismometers (OBS). Studies of attenuation in marine environments must overcome unique challenges associated with strong oceanographic noise at the seafloor and data loss during OBS recovery in addition to untangling the competing influences of elastic focusing, local site amplification, and anelastic attenuation on surface-wave amplitudes. We apply Helmholtz tomography to OBS data to simultaneously resolve array-averaged Rayleigh wave attenuation and maps of site amplification at periods of 20{\textendash}150 s. The approach explicitly accounts for elastic focusing and defocusing due to lateral velocity heterogeneity using wavefield curvature. We validate the approach using realistic wavefield simulations at the NoMelt Experiment and Juan de Fuca (JdF) plate, which represent endmember open-ocean and coastline-adjacent environments, respectively. Focusing corrections are successfully recovered at both OBS arrays, including at periods < 35 s at JdF where coastline effects result in strong multipathing. When applied to real data, our observations of Rayleigh wave attenuation at NoMelt and JdF revise previous estimates. At NoMelt, we observe a low attenuation lithospheric layer (Qμ>1500) overlying a highly attenuating asthenospheric layer (Qμ\~{}50{\textendash}70). At JdF, we find a broad peak in attenuation (Qμ\~{}50{\textendash}60) centered at a depth of 100{\textendash}130 km. We also report strong local site amplification at the JdF Ridge (>10\% at 31 s period), which can be used to refine models of crust and shallow mantle structure.},
	keywords = {amplification, attenuation, Helmholtz, ocean-bottom seismology, surface waves, tomography},
	issn = {2169-9356},
	doi = {10.1029/2022JB025174},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JB025174},
	author = {Russell, Joshua B. and Dalton, Colleen A.}
}
@article {le_seismic_2022,
	title = {Seismic Constraints on Crustal and Uppermost Mantle Structure Beneath the Hawaiian Swell: Implications for Plume-Lithosphere Interactions},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {127},
	number = {11},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2021JB023822},
	month = {10/2022},
	pages = {e2021JB023822},
	abstract = {We infer the lithospheric structure beneath the Hawaiian Swell based on a joint inversion of ambient noise and teleseismic Rayleigh waves collected during the PLUME experiment. These combined datasets let us use Rayleigh waves with a period range of 8{\textendash}50 s that provides imaging resolution for the shallow lithosphere and constrains interactions between the upwelling plume and migrating plate. We find an elongated low-velocity anomaly beneath the lithosphere along the island chain that connects to the plume conduit, consistent with the melting region associated with a restite hotspot swell root that has mechanically eroded the base of its overlying lithosphere. It could also be consistent with a plume refracted by the overriding plate motion if the plume could manage to deeply erode the lithospheric base, as only a more viscous restite root is seen to do in thermomechanical experiments. There is also a low-velocity body beneath the North Arch that coincides with the location of recent off-chain volcanic fields discovered there. Its location relative to the Molokai Fracture Zone (MFZ) supports the concept that swell-root material has preferentially spread beneath the younger side of the MFZ. We also find a clear low-velocity anomaly associated with the uppermost \~{}50 km of the fracture zone lithosphere. The relatively well-resolved shallow lithospheric structure determined here allows us to estimate the volumes of underplating and the total flux of the rising plume material that is added beneath the Hawaiian lithosphere, which we constrain to be in the range of 0.5{\textendash}0.6 km3/yr.},
	keywords = {ambient noise, Hawaiian swell, Rayleigh waves, tomography, underplating},
	issn = {2169-9356},
	doi = {10.1029/2021JB023822},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021JB023822},
	author = {Le, Ba Manh and Yang, Ting and Morgan, Jason P.}
}
@article {christeson_seismic_2022,
	title = {Seismic evidence for magmatic underplating along the Kodiak-Bowie Seamount Chain, Gulf of Alaska},
	journal = {Tectonophysics},
	volume = {845},
	year = {2022},
	month = {11/2022},
	pages = {229639},
	abstract = {Oceanic crust formed at mid-ocean ridges may be later modified by off-ridge magmatism forming seamounts, guyots, and islands. We investigate processes associated with seamount formation in the Gulf of Alaska Seamount Province using two coincident seismic reflection/wide-angle profiles. A north-south profile crosses the Kodiak-Bowie Seamount Chain and Aja fracture zone (FZ), and an orthogonal east-west profile is located about 90~km south of the seamount chain over Pacific plate oceanic crust. Structure along the profile away from the seamount chain is consistent with typical oceanic crust. Crust in our study region is thinnest (about 5.6~km) at the Aja FZ. Unlike observations from active transform faults, no low-velocity anomaly is observed at the Aja FZ suggesting that the crustal velocities have recovered to normal values through crack closure and crack healing. Higher lower crustal velocities (\~{}7.3 and~>~7.5~km/s) and thicker crust (\~{}8.5 and~\~{}7.0~km) are observed near the Pratt and Durgin Seamounts and at the intersection of the Kodiak-Bowie Seamount Chain linear trend, respectively. These observations are attributed to magmatic underplating associated with seamount province magmatism. Lithospheric thickness variations across the Aja FZ may form a barrier or impediment to magmatic flow. The thickest crust (8.5~km) along our two profiles is located on the younger side of the FZ, and we suggest that the majority of magmatism jumped south of the Aja FZ when thinner lithosphere was encountered by the Bowie hot spot. The crustal structure near the Kodiak-Bowie Seamount Chain is most similar to that of other seamounts and guyots that formed on similarly young lithosphere (8{\textendash}12~Ma). Our results suggest that lithospheric thickness at the time of hot spot interaction has a large control on magmatic underplating at seamounts and seamount provinces.},
	keywords = {Fracture zone, Magmatic underplating, Seamount},
	issn = {0040-1951},
	doi = {10.1016/j.tecto.2022.229639},
	url = {https://www.sciencedirect.com/science/article/pii/S0040195122004334},
	author = {Christeson, Gail L. and Gulick, Sean P. S. and Walton, Maureen A. L. and Barth, Ginger A.}
}
@article {xu_seismic_2022,
	title = {A Seismic Tomography, Gravity, and Flexure Study of the Crust and Upper Mantle Structure of the Emperor Seamounts at Jimmu Guyot},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {127},
	number = {6},
	year = {2022},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2021JB023241},
	month = {05/2022},
	pages = {e2021JB023241},
	abstract = {The intraplate Hawaiian-Emperor Seamount Chain has long been considered a hotspot track generated by the motion of the Pacific plate over a deep mantle plume, and an ideal feature therefore for studies of volcanic structure, magma supply, plume-crust interaction, flexural loading, and upper mantle rheology. Despite their importance as a major component of the chain, the Emperor Seamounts have been relatively little studied. In this paper, we present the results of an active-source wide-angle reflection and refraction experiment conducted along an ocean-bottom-seismograph (OBS) line oriented perpendicular to the seamount chain, crossing Jimmu guyot. The tomographic P wave velocity model, using \~{}20,000 travel times from 26 OBSs, suggests that there is a high-velocity (>6.0 km/s) intrusive core within the edifice, and the extrusive-to-intrusive ratio is estimated to be \~{}2.5, indicating that Jimmu was built mainly by extrusive processes. The total volume for magmatic material above the top of the oceanic crust is \~{}5.3 {\texttimes} 104 km3, and the related volume flux is \~{}0.96 m3/s during the formation of Jimmu. Under volcanic loading, the \~{}5.3-km-thick oceanic crust is depressed by \~{}3.8 km over a broad region. Using the standard relationships between Vp and density, the velocity model is verified by gravity modeling, and plate flexure modeling indicates an effective elastic thickness (Te) of \~{}14 km. Finally, we find no evidence for large-scale magmatic underplating beneath the pre-existing crust.},
	keywords = {Emperor Seamounts, gravity modeling, oceanic crust, plate flexure, seamount structure, seismic tomography},
	issn = {2169-9356},
	doi = {10.1029/2021JB023241},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021JB023241},
	author = {Xu, C. and Dunn, R. A. and Watts, A. B. and Shillington, D. J. and Grevemeyer, I. and G{\'o}mez de la Pe{\~n}a, L. and Boston, B. B.}
}
@article {gong_seismicity_2022,
	title = {Seismicity, fault architecture, and slip mode of the westernmost Gofar transform fault},
	journal = {Journal of Geophysical Research: Solid Earth},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2022JB024918},
	month = {10/2022},
	pages = {e2022JB024918},
	abstract = {Oceanic transform faults accommodate plate motions through both seismic and aseismic slips. However, deformation partition and slip mode interaction at these faults remain elusive mainly limited by rare observations. We use one-year ocean bottom seismometer data collected in 2008 to detect and locate earthquakes at the westernmost Gofar transform fault. The ultra-fast slipping rate of Gofar results in \~{}30,000 earthquakes during the observational period, providing an excellent opportunity to investigate interrelations between the slip mode, seismicity, and fault architecture at an unprecedented resolution. Earthquake distribution indicates that the \~{}100 km long Gofar transform fault is distinctly segmented into five zones, including one zone contouring a M6 earthquake that was captured by the experiment. Further, a barrier zone east of the M6 earthquake hosted abundant foreshocks preceding the M6 event and halted its active seismicity afterwards. The barrier zone has two layers of earthquakes at depth, and they responded to the M6 earthquake differently. Additionally, a zone connecting to the East Pacific Rise had quasi-periodic earthquake swarms. The seismicity segmentation suggests that the Gofar fault has multiple slip modes occurring in adjacent fault patches. Spatiotemporal characteristics of the earthquakes suggest that complex fault architecture and fluid-rock interaction play primary roles in modulating the slip modes at Gofar, possibly involving multiple concurrent physical processes.},
	keywords = {fault slip, fluid-rock interaction, fluid{\textendash}rock interaction, microseismicity, miroseismicity, oceanic transform faults},
	issn = {2169-9356},
	doi = {10.1029/2022JB024918},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JB024918},
	author = {Gong, Jianhua and Fan, Wenyuan}
}
@article {russell_seismological_2022,
	title = {Seismological Evidence for Girdled Olivine Lattice-Preferred Orientation in Oceanic Lithosphere and Implications for Mantle Deformation Processes During Seafloor Spreading},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {23},
	number = {10},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2022GC010542},
	pages = {e2022GC010542},
	abstract = {Seismic anisotropy produced by aligned olivine in oceanic lithosphere offers a window into mid-ocean ridge (MOR) dynamics. Yet, interpreting anisotropy in the context of grain-scale deformation processes and strain observed in laboratory experiments and natural olivine samples has proven challenging due to incomplete seismological constraints and length scale differences spanning orders of magnitude. To bridge this observational gap, we estimate an in situ elastic tensor for oceanic lithosphere using co-located compressional- and shear-wavespeed anisotropy observations at the NoMelt experiment located on \~{}70 Ma seafloor. The elastic model for the upper 7 km of the mantle, NoMelt_SPani7, is characterized by a fast azimuth parallel to the fossil-spreading direction, consistent with corner-flow deformation fabric. We compare this model with a database of 123 petrofabrics from the literature to infer olivine crystallographic orientations and shear strain accumulated within the lithosphere. Direct comparison to olivine deformation experiments indicates strain accumulation of 250\%{\textendash}400\% in the shallow mantle. We find evidence for D-type olivine lattice-preferred orientation (LPO) with fast [100] parallel to the shear direction and girdled [010] and [001] crystallographic axes perpendicular to shear. D-type LPO implies similar amounts of slip on the (010)[100] and (001)[100] easy slip systems during MOR spreading; we hypothesize that grain-boundary sliding during dislocation creep relaxes strain compatibility, allowing D-type LPO to develop in the shallow lithosphere. Deformation dominated by dislocation-accommodated grain-boundary sliding (disGBS) has implications for in situ stress and grain size during MOR spreading and implies grain-size dependent deformation, in contrast to pure dislocation creep.},
	keywords = {grain-boundary sliding, mid-ocean ridge, oceanic lithosphere, seafloor spreading, seismic anisotropy, surface waves},
	issn = {1525-2027},
	doi = {10.1029/2022GC010542},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022GC010542},
	author = {Russell, J. B. and Gaherty, J. B. and Mark, H. F. and Hirth, G. and Hansen, L. N. and Lizarralde, D. and Collins, J. A. and Evans, R. L.}
}
@article {boulahanis_structure_2022,
	title = {Structure and Evolution of Northern Juan de Fuca Crust and Uppermost Mantle Over the Last 8 Ma From an Active-Source Seismic Tomography Study},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {127},
	number = {9},
	year = {2022},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022JB023987},
	month = {08/2022},
	pages = {e2022JB023987},
	abstract = {We present results from a two-dimensional wide-angle controlled source seismic transect designed to characterize the velocity structure of the oceanic crust and uppermost mantle spanning the northern Juan de Fuca (JdF) plate from near Endeavor ridge to the Cascadia margin. Reflection and refraction travel time inversion is used to derive a tomographic Vp model of sediments, crust, and upper mantle. Velocity model results are compared to baseline reference Vp values for unaltered crustal and upper mantle rocks at temperatures assuming plate cooling. Effective medium theory is used to infer the degree of hydration of the crust and mantle. Results indicate a somewhat fractured and hydrated upper crust (<=2.5 wt\% water), a near dry lower crust (<=0.7 wt\%) and upper mantle (<=0.5 wt\%) west of the deformation front, and an \~{}75 km wide region of modestly lower velocity in the mid-plate. Comparison with prior results from a complementary transect offshore Oregon indicates significant differences in Vp of the upper crust, with lower Vp-inferred porosity along most of the Washington transects that may reflect different extents of fault-related alteration and sediment burial histories. Approaching the deformation front, Washington transect Vp structure indicates dryer conditions than offshore Oregon, consistent with differences in extent of subduction bend faulting found in reflection imaging studies. On both transects, quasi-abrupt changes in plate properties at ages of 8, 6, and 3.4/4 Ma are found. Distinct crustal accretion modes are recognized, aligning with changes in JdF plate motion and recent history of Cobb-Eickelberg hotspot influence on crustal accretion at the JdF ridge.},
	issn = {2169-9356},
	doi = {10.1029/2022JB023987},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JB023987},
	author = {Boulahanis, Bridgit and Carbotte, Suzanne M. and Canales, Juan Pablo and Han, Shuoshuo and Nedimovi{\'c}, Mladen R.}
}
@article {eilon_sub-lithospheric_2022,
	title = {Sub-Lithospheric Small-Scale Convection Tomographically Imaged Beneath the Pacific Plate},
	journal = {Geophysical Research Letters},
	volume = {49},
	number = {18},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2022GL100351},
	month = {09/2022},
	pages = {e2022GL100351},
	abstract = {Small-scale convection beneath the oceanic plates has been invoked to explain off-axis nonplume volcanism, departure from simple seafloor depth-age relationships, and intraplate gravity lineations. We deployed 30 broadband ocean bottom seismometer stations on \~{}40 Ma Pacific seafloor in a region notable for gravity anomalies, measured by satellite altimetry, elongated parallel to plate motion. P-wave teleseismic tomography reveals alternating upper mantle velocity anomalies on the order of {\textpm}2\%, aligned with the gravity lineations. These features, which correspond to \~{}300{\textdegree}{\textendash}500{\textdegree}K lateral temperature contrast, and possible hydrous or carbonatitic partial melt, are{\textemdash}surprisingly{\textemdash}strongest between 150 and 260 km depth, indicating rapid vertical motions through a low-viscosity asthenospheric channel. Coherence and admittance analysis of gravity and topography using new multibeam bathymetry soundings substantiates the presence of mantle density variations, and forward modeling predicts gravity anomalies that qualitatively match observed lineations. This study provides observational support for small-scale convective rolls beneath the oceanic plates.},
	keywords = {asthenosphere, body wave tomography, mantle convection, ocean bottom seismometer, oceanic lithosphere},
	issn = {1944-8007},
	doi = {10.1029/2022GL100351},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022GL100351},
	author = {Eilon, Zachary C. and Zhang, Lun and Gaherty, James B. and Forsyth, Donald W. and Russell, Joshua B.}
}
@article {wang_temporal_2022,
	title = {Temporal velocity variations in the northern Hikurangi margin and the relation to slow slip},
	journal = {Earth and Planetary Science Letters},
	volume = {584},
	year = {2022},
	month = {04/2022},
	pages = {117443},
	abstract = {Slow slip events (SSE) have been studied in increasing detail over the last 20 years, improving our understanding of subduction zone processes. Although the relationship between SSEs and the physical properties of their surrounding materials is still not well-understood, the northern Hikurangi margin in New Zealand is the site of relatively shallow (<10 km deep), frequent SSEs, providing excellent opportunities for near-field investigations. From September to October 2014, an SSE occurred with more than 250 mm slip, and was recorded successfully by the Hikurangi Ocean Bottom Investigation of Tremor and Slow Slip (HOBITSS) deployment. This study applies scattered wave interferometry to ambient noise data acquired by nine HOBITSS ocean bottom seismometers (OBS) to study the seismic velocity variations related to the SSE. Single station cross-component correlations are computed within a period band that focuses on the upper plate in our study region. The average velocity variations display a decrease on the order of 0.05\% during the SSE, followed by an increase of similar magnitude afterwards. We suggest two possibilities. The first possibility, which has been suggested by other seismological observations, is that the SSE causes a low-permeability seal on the plate boundary to break. The break allows fluid to migrate into the upper plate, causing a seismic velocity decrease during the SSE because of increased pore fluid volume in the upper plate. Under this model, after the SSE, the fluids in the upper plate diffuse gradually and the velocity increases again. The second possibility is the velocity changes are related to changes in crustal strain during the slow slip cycle, whereby elastic strain accumulates prior to the SSE, causing contraction and reduction of porosity and therefore increase of velocity above the SSE source (the seismic velocity increases between SSEs). During the SSE the upper plate goes into extension as the elastic strain is released, which results in dilation and a porosity increase (seismic velocity reduction). After the SSE, stress and strain accumulate again, causing a porosity decrease and a velocity increase.},
	keywords = {ambient noise, seismic velocity variations, slow slip event, the Hikurangi subduction zone},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2022.117443},
	url = {https://www.sciencedirect.com/science/article/pii/S0012821X22000796},
	author = {Wang, Weiwei and Savage, Martha K. and Yates, Alexander and Zal, Hubert J. and Webb, Spahr and Boulton, Carolyn and Warren-Smith, Emily and Madley, Megan and Stern, Tim and Fry, Bill and Mochizuki, Kimihiro and Wallace, Laura}
}
@article {deng_theoretical_2022,
	title = {Theoretical Solution and Applications of Ocean Bottom Pressure Induced by Seismic Waves at High Frequencies},
	journal = {Geophysical Research Letters},
	volume = {49},
	number = {9},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2021GL096952},
	pages = {e2021GL096952},
	abstract = {Previous studies have demonstrated that the ocean-bottom pressure associated with seismic seafloor motion is linearly proportional to the vertical seafloor acceleration, for frequencies much lower than the resonance frequency of water layer (c0/4h, c0 water sound speed, h water depth). In this article, we use realistic observations to verify a theoretical relation between the ocean-bottom pressure and vertical acceleration up to the water resonance frequency. We then show two applications of the theoretical relation. First, the pressure amplitude recorded by differential pressure gauges is calibrated, and the calibration coefficient is found to vary by frequency. Second, Rayleigh wave phase velocity near the water resonance frequency can be calculated from recordings of pressure and vertical seafloor acceleration at a single station, which is useful to constrain the shallow Earth structure.},
	issn = {1944-8007},
	doi = {10.1029/2021GL096952},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021GL096952},
	author = {Deng, Han and An, Chao and Cai, Chen and Ren, Hengxin}
}
@article {harmon_tilt_2022,
	title = {Tilt Corrections for Normal Mode Observations on Ocean Bottom Seismic Data, an example from the PI-LAB experiment},
	journal = {Seismica},
	volume = {1},
	number = {1},
	year = {2022},
	note = {Number: 1},
	month = {11/2022},
	abstract = {Earth{\textquoteright}s normal modes are fundamental observations used in global seismic tomography to understand Earth structure. Land seismic station coverage is sufficient to constrain the broadest scale Earth structures. However, 70\% of Earth{\textquoteright}s surface is covered by the oceans, hampering our ability to observe variations in local mode frequencies that contribute to imaging small-scale structures. Broadband ocean bottom seismometers can record spheroidal modes to fill in gaps in global data coverage. Ocean bottom recordings are contaminated by signals from complex interactions between ocean and solid Earth dynamics at normal mode frequencies. We present a method for correcting tilt on broadband ocean bottom seismometers by rotation. The correction improves the ability of some instruments to observe spheroidal modes down to 0S4. We demonstrate this method using 15 broadband ocean bottom seismometers from the PI-LAB array. We measure normal mode peak frequency shifts and compare with 1-D reference mode frequencies and predictions from 3-D global models. Our measurements agree with the 3-D models for modes between 0S14 - 0S37 with small but significant differences. These differences likely reflect real Earth structure. This suggests incorporating ocean bottom normal mode measurements into global inversions will improve models of global seismic velocity structure.},
	keywords = {marine geophysics, normal modes, ocean bottom seismometer},
	issn = {2816-9387},
	doi = {10.26443/seismica.v1i1.196},
	url = {https://seismica.library.mcgill.ca/article/view/196},
	author = {Harmon, Nicholas and Laske, Gabi and Crawford, Wayne and Rychert, Catherine}
}
@article {cabieces_upper-lithospheric_2022,
	title = {Upper-lithospheric structure of northeastern Venezuela from joint inversion of surface-wave dispersion and receiver functions},
	journal = {Solid Earth},
	volume = {13},
	number = {11},
	year = {2022},
	note = {Publisher: Copernicus GmbH},
	month = {11/2022},
	pages = {1781{\textendash}1801},
	abstract = {We use 1.5 years of continuous recordings from an amphibious seismic network deployment in the region of northeastern South America and the southeastern Caribbean to study the crustal and uppermost mantle structure through a joint inversion of surface-wave dispersion curves determined from ambient seismic noise and receiver functions. The availability of both ocean bottom seismometers (OBSs) and land stations makes this experiment ideal to determine the best processing methods to extract reliable empirical Green{\textquoteright}s functions (EGFs) and construct a 3D shear velocity model. Results show EGFs with high signal-to-noise ratio for land{\textendash}land, land{\textendash}OBS and OBS{\textendash}OBS paths from a variety of stacking methods. Using the EGF estimates, we measure phase and group velocity dispersion curves for Rayleigh and Love waves. We complement these observations with receiver functions, which allow us to perform an H-k analysis to obtain Moho depth estimates across the study area. The measured dispersion curves and receiver functions are used in a Bayesian joint inversion to retrieve a series of 1D shear-wave velocity models, which are then interpolated to build a 3D model of the region. Our results display clear contrasts in the oceanic region across the border of the San Sebastian{\textendash}El Pilar strike-slip fault system as well as a high-velocity region that corresponds well with the continental craton of southeastern Venezuela. We resolve known geological features in our new model, including the Espino Graben and the Guiana Shield provinces, and provide new information about their crustal structures. Furthermore, we image the difference in the crust beneath the Matur{\'\i}n and Gu{\'a}rico sub-basins.},
	issn = {1869-9510},
	doi = {10.5194/se-13-1781-2022},
	url = {https://se.copernicus.org/articles/13/1781/2022/},
	author = {Cabieces, Roberto and Arnaiz-Rodr{\'\i}guez, Mariano S. and Villase{\~n}or, Antonio and Berg, Elizabeth and Olivar-Casta{\~n}o, Andr{\'e}s and Ventosa, Sergi and Ferreira, Ana M. G.}
}
@article {chaudhuri_widespread_2022,
	title = {Widespread Very Low Frequency Earthquakes (VLFEs) Activity Offshore Cascadia},
	journal = {Geophysical Research Letters},
	volume = {49},
	number = {13},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2022GL097962},
	pages = {e2022GL097962},
	abstract = {A significant amount of stress in the Cascadia subduction zone (CSZ) is released by different forms of slow earthquakes including tremors, low-frequency earthquakes, and very low-frequency earthquakes (VLFEs){\textemdash}all occurring onshore at the deeper part of the transition zone. Their activity offshore, however, remains elusive. We discover widespread occurrence of discrete VLFEs offshore Cascadia using ocean-bottom seismometers. Barring occasional regular fast earthquakes, VLFEs are the only seismic stress indicators offshore. Using centroid moment tensor inversion and matched filtering, we detect sequences of 12 distinct families of VLFEs. The VLFEs in northern CSZ have focal mechanisms consistent with the area{\textquoteright}s subduction zone deformation. Interestingly, the VLFEs in the southern part of CSZ show strike-slip faulting, attributed to offshore faults, sediment consolidation, subduction bending, and transpressional regimes created by complex plate tectonics. It challenges a canonical view of the seismogenic zone in Cascadia characterized by a frictionally homogeneous fault segment producing only regular fast earthquakes.},
	issn = {1944-8007},
	doi = {10.1029/2022GL097962},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022GL097962},
	author = {Chaudhuri, Kuntal and Ghosh, Abhijit}
}
@article {feng_amphibious_2021,
	title = {Amphibious Shear Wave Structure Beneath the Alaska-Aleutian Subduction Zone From Ambient Noise Tomography},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {22},
	number = {5},
	year = {2021},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2020GC009438},
	pages = {e2020GC009438},
	abstract = {I present a 3-D isotropic shear wave velocity model of the crust and uppermost mantle beneath the Alaska-Aleutian subduction zone offshore of the Alaska Peninsula, based on seismic data recorded by the Alaska Amphibious Community Seismic Experiment (AACSE) array and some other networks. The model derives from Rayleigh wave phase speed measurements extracted from ambient seismic noise. A new three-station interferometry (Zhang et al., 2020) approach is applied to improve the data coverage of ambient noise surface waves. Based on the ambient noise Rayleigh wave dispersion data, a Bayesian Monte Carlo inversion is performed to produce the shear wave velocity model. There are several prominent structures captured by the model, including: (1) The major sedimentary basins across the study region are identified by model. (2) Crustal thickness estimates are related with the geological structures. (3) The imaged slab edge is consistent with both the Slab 2.0 model (Hayes et al., 2018) and earthquake locations. And lots of geological and tectonic features related to subduction zone are captured, including the serpentinized forearc and partial melting zone beneath the Aleutian arc volcanoes. (4) Near the Shumagin gap, reduction in Vs is observed at the uppermost part of the incoming Pacific plate, consistent with the active source study of Shillington et al. (2015). The Vs reduction reflects hydration of the oceanic plate which could be related to local seismicity variation.},
	issn = {1525-2027},
	doi = {10.1029/2020GC009438},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020GC009438},
	author = {Feng, Lili}
}
@article {lynner_anisotropy-revealed_2021,
	title = {Anisotropy-revealed change in hydration along the Alaska subduction zone},
	journal = {Geology},
	volume = {49},
	number = {9},
	year = {2021},
	pages = {1122{\textendash}1125},
	abstract = {Megathrust earthquake behavior in subduction zones is controlled by a variety of factors including the hydration state of the subducting slab. Increased hydration reduces the occur-rence of great, damaging earthquakes by diminishing the strength of the material along the interface between tectonic plates. Understanding variations in hydration in subductions zones is necessary for properly assessing the overall hazard posed by each region. Fortunately, seismic anisotropy is strongly dependent upon hydration of the subducting crust and litho-sphere. I present shear-wave splitting measurements that illuminate changes in anisotropy, and therefore hydration, of the subducting Pacific plate beneath the Alaska subduction zone (northern Pacific Ocean). Variations in shear-wave splitting directly correlate to changes in the behavior of great, megathrust earthquakes. My measurements show that the Shumagin seismic gap is characterized by a hydrated subducting slab, explaining the long-term lack of great earthquakes. Observations in the immediately adjacent Semidi segment, which experiences great events regularly, indicate a far less hydrated slab. These results are driven by the preferential alignment of paleo-spreading fabrics of the Pacific plate. Where fabrics are more closely aligned with the orientation of the trench, outer-rise faulting and plate hydration is enhanced. These results highlight the importance of changes in preexisting slab structures and subsequent hydration in the production of great, damaging earthquakes.},
	issn = {0091-7613},
	doi = {10.1130/G48860.1},
	url = {https://doi.org/10.1130/G48860.1},
	author = {Lynner, Colton}
}
@article {kleckner_automated_2021,
	title = {Automated Detection of Clipping in Broadband Earthquake Records},
	journal = {Seismological Research Letters},
	volume = {93},
	number = {2A},
	year = {2021},
	month = {dec},
	pages = {880{\textendash}896},
	abstract = {Because the amount of available ground-motion data has increased over the last decades, the need for automated processing algorithms has also increased. One difficulty with automated processing is to screen clipped records. Clipping occurs when the ground-motion amplitude exceeds the dynamic range of the linear response of the instrument. Clipped records in which the amplitude exceeds the dynamic range are relatively easy to identify visually yet challenging for automated algorithms. In this article, we seek to identify a reliable and fully automated clipping detection algorithm tailored to near-real-time earthquake response needs. We consider multiple alternative algorithms, including (1)~an algorithm based on the percentage difference in adjacent data points, (2)~the standard deviation of the data within a moving window, (3)~the shape of the histogram of the recorded amplitudes, (4)~the second derivative of the data, and (5)~the amplitude of the data. To quantitatively compare these algorithms, we construct development and holdout datasets from earthquakes across a range of geographic regions, tectonic environments, and instrument types. We manually classify each record for the presence of clipping and use the classified records. We then develop an artificial neural network model that combines all the individual algorithms. Testing on the holdout dataset, the standard deviation and histogram approaches are the most accurate individual algorithms, with an overall accuracy of about 93\%. The combined artificial neural network method yields an overall accuracy of 95\%, and the choice of classification threshold can balance precision and recall.},
	issn = {0895-0695},
	doi = {10.1785/0220210028},
	url = {https://doi.org/10.1785/0220210028},
	author = {Kleckner, James K. and Withers, Kyle B. and Thompson, Eric M. and Rekoske, John M. and Wolin, Emily and Moschetti, Morgan P.}
}
@article {gosselin_azimuthal_2021,
	title = {Azimuthal anisotropy in Bayesian surface wave tomography: application to northern Cascadia and Haida Gwaii, British Columbia},
	journal = {Geophysical Journal International},
	volume = {224},
	number = {3},
	year = {2021},
	month = {mar},
	pages = {1724{\textendash}1741},
	abstract = {Surface wave tomography is a valuable tool for constraining azimuthal anisotropy at regional scales. However, sparse and uneven coverage of dispersion measurements make meaningful uncertainty estimation challenging, especially when applying subjective model regularization. This paper considers azimuthal anisotropy constrained by measurements of surface wave dispersion data within a Bayesian trans-dimensional (trans-d) tomographic inversion. A recently proposed alternative model parametrization for trans-d inversion is implemented in order to produce more realistic models than previous studies considering trans-d surface wave tomography. The reversible-jump Markov chain Monte Carlo sampling technique is used to numerically estimate the posterior probability density of the model parameters. Isotropic and azimuthally anisotropic components of surface wave group velocity maps (and their associated uncertainties) are estimated while avoiding model regularization and allowing model complexity to be determined by the data information content. Furthermore, data errors are treated as unknown, and solved for within the inversion. The inversion method is applied to measurements of surface wave dispersion from regional earthquakes recorded over northern Cascadia and Haida Gwaii, a region of complex active tectonics but highly heterogeneous station coverage. Results for isotropic group velocity are consistent with previous studies that considered the southern part of the study region over Cascadia. Azimuthal anisotropic fast-axis directions are generally margin-parallel between Vancouver Island and Haida Gwaii, with a small change in direction and magnitude along the margin which may be attributed to the changing tectonic regime (from subduction to transform tectonics). Estimated errors on the dispersion data (solved for within the inversion) reveal a correlation between surface wave period and the dependence of data errors on travel path length. This paper demonstrates the value of considering azimuthal anisotropy within Bayesian tomographic inversions. Furthermore, this work provides structural context for future studies of tectonic structure and dynamics of northern Cascadia and Haida Gwaii, with the aim of improving our understanding of seismic and tsunami hazards.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggaa561},
	url = {https://doi.org/10.1093/gji/ggaa561},
	author = {Gosselin, Jeremy M and Audet, Pascal and Schaeffer, Andrew J and Darbyshire, Fiona A and Est{\`e}ve, Cl{\'e}ment}
}
@article {essing_characteristics_2021,
	title = {Characteristics of Current-Induced Harmonic Tremor Signals in Ocean-Bottom Seismometer Records},
	journal = {Seismological Research Letters},
	volume = {92},
	number = {5},
	year = {2021},
	pages = {3100{\textendash}3112},
	abstract = {Long-lasting harmonic tremor signals are frequently observed in spectrograms of seismological data. Natural sources, such as volcanoes and icebergs, or artificial sources, such as ships and helicopters, produce very similar harmonic tremor episodes. Ocean-bottom seismometer (OBS) records may additionally be contaminated by tremor induced by ocean-bottom currents acting on the OBS structure. This harmonic tremor noise may severely hinder earthquake detection and can be misinterpreted as volcanic tremor.In a 160-km-long network of 27 OBSs deployed for 1~yr along the Knipovich ridge in the Greenland Sea, harmonic tremor was widely observed away from natural sources such as volcanoes. Based on this network, we present a systematic analysis of the characteristics of hydrodynamically induced harmonic tremor in OBS records to make it distinguishable from natural tremor sources and reveal its generation processes.We apply an algorithm that detects harmonic tremor and extracts time series of its fundamental frequency and spectral amplitude. Tremor episodes typically occur twice per day, starting with fundamental frequencies of 0.5{\textendash}1.0~Hz, and show three distinct stages that are characterized by frequency-gliding, mode-locking, and large spectral amplitudes, respectively. We propose that ocean-bottom currents larger than \~{}5  cm/s cause rhythmical Karman vortex shedding around protruding structures of the OBS and excite eigenvibrations. Head-buoy strumming is the most likely source of the dominant tremor signal, whereas a distinctly different tremor signal with a fundamental frequency \~{}6  Hz may be related to eigenvibrations of the radio antenna. Ocean-bottom current velocities reconstructed from the fundamental tremor frequency and from cross correlation of tremor time series between stations match observed average current velocities of 14{\textendash}20  cm/s in this region. The tremor signal periodicity shows the same tidal constituents as the forcing ocean-bottom currents, which is a further evidence of the hydrodynamic nature of the tremor.},
	issn = {0895-0695},
	doi = {10.1785/0220200397},
	url = {https://doi.org/10.1785/0220200397},
	author = {Essing, David and Schlindwein, Vera and Schmidt-Aursch, Mechita C. and Hadziioannou, Celine and St{\"a}hler, Simon C.}
}
@article {an_characteristics_2021,
	title = {Characteristics of Low-Frequency Horizontal Noise of Ocean-Bottom Seismic Data},
	journal = {Seismological Research Letters},
	volume = {93},
	number = {1},
	year = {2021},
	pages = {257{\textendash}267},
	abstract = {Horizontal records of ocean-bottom seismographs are usually noisy at low frequencies (\&lt; 0.1~Hz). The noise source is believed to be associated with ocean-bottom currents that may tilt the instrument. Currently horizontal records are mainly used to remove the coherent noise in vertical records, and there has been little literature that quantitatively discusses the mechanism and characteristics of low-frequency horizontal noise. In this article, we analyze in situ ocean-bottom measurements by rotating the data horizontally and evaluating the coherency between different channels. Results suggest that the horizontal noise consists of two components, random noise and principle noise whose direction barely changes in time. The amplitude and the direction of the latter are possibly related to the intensity and direction of ocean-bottom currents. Rotating the horizontal records to the direction of the principle noise can largely suppress the principle noise in the orthogonal horizontal channel. In addition, the horizontal noise is incoherent with pressure, indicating that the noise source is not ocean surface water waves (infragravity waves). At some stations in shallow waters (\&lt;300~m), horizontal noise around 0.07~Hz is found to be linearly proportional to the temporal derivative of pressure, which is explained by forces of added mass due to infragravity waves.},
	issn = {0895-0695},
	doi = {10.1785/0220200349},
	url = {https://doi.org/10.1785/0220200349},
	author = {An, Chao and Cai, Chen and Zhou, Lei and Yang, Ting}
}
@article {mark_constraints_2021,
	title = {Constraints on the Depth, Thickness, and Strength of the G Discontinuity in the Central Pacific From S Receiver Functions},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {126},
	number = {4},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2019JB019256},
	month = {03/2021},
	pages = {e2019JB019256},
	abstract = {The relative motion of the lithosphere with respect to the asthenosphere implies the existence of a boundary zone that accommodates shear between the rigid plates and flowing mantle. This shear zone is typically referred to as the lithosphere-asthenosphere boundary (LAB). The width of this zone and the mechanisms accommodating shear across it have important implications for coupling between mantle convection and surface plate motion. Seismic observations have provided evidence for several physical mechanisms that might help enable relative plate motion, but how these mechanisms each contribute to the overall accommodation of shear remains unclear. Here we present receiver function constraints on the discontinuity structure of the oceanic upper mantle at the NoMelt site in the central Pacific, where local constraints on shear velocity, anisotropy, conductivity, and attenuation down to \~{}300 km depth provide a comprehensive picture of upper mantle structure. We image a seismic discontinuity with a Vsv decrease of 4.5\% or more over a 0{\textendash}20 km thick gradient layer centered at a depth of \~{}65 km. We associate this feature with the Gutenberg discontinuity (G), and interpret our observation of G as resulting from strain localization across a dehydration boundary based on the good agreement between the discontinuity depth and that of the dry solidus. Transitions in Vsv, azimuthal anisotropy, conductivity, and attenuation observed at roughly similar depths suggest that the G discontinuity represents a region of localized strain within a broader zone accommodating shear between the lithosphere and asthenosphere.},
	issn = {2169-9356},
	doi = {10.1029/2019JB019256},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JB019256},
	author = {Mark, H. F. and Collins, J. A. and Lizarralde, D. and Hirth, G. and Gaherty, J. B. and Evans, R. L. and Behn, M. D.}
}
@article {gong_constraints_2021,
	title = {Constraints on the Geometry of the Subducted Gorda Plate From Converted Phases Generated by Local Earthquakes},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {126},
	number = {2},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020JB019962},
	month = {01/2021},
	pages = {e2020JB019962},
	abstract = {The largest slip in great megathrust earthquakes often occurs in the 10{\textendash}30 km depth range, yet seismic imaging of the material properties in this region has proven difficult. We utilize a dense onshore-offshore passive seismic dataset from the southernmost Cascadia subduction zone where seismicity in the mantle of the subducted Gorda Plate produces S-to-P and P-to-S conversions generated within a few km of the plate interface. These conversions typically occur in the 10{\textendash}20 km depth range at either the top or bottom of a \~{}5 km thick layer with a high Vp/Vs that we infer to be primarily the subducted crust. We use their arrival times and amplitudes to infer the location of the top and bottom of the subducted crust as well as the velocity contrasts across these discontinuities. Comparing with both the Slab1.0 and the updated Slab2 interface models, the Slab2 model is generally consistent with the converted phases, while the Slab1.0 model is 1{\textendash}2 km deeper in the 2{\textendash}20 km depth range and \~{}6{\textendash}8 km too deep in the 10{\textendash}20 km depth range between 40.25{\textdegree}N and 40.4{\textdegree}N. Comparing the amplitudes of the converted phases to synthetics for simplified velocity structures, the amplitude of the converted phases requires models containing a \~{}5 km thick zone with at least a \~{}10\%{\textendash}20\% reduction in S wave velocity. Thus, the plate boundary is likely contained within or at the top of this low velocity zone, which potentially indicates a significant porosity and fluid content within the seismogenic zone.},
	keywords = {converted phases, seismic imaging, subduction zone plate boundary},
	issn = {2169-9356},
	doi = {10.1029/2020JB019962},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020JB019962},
	author = {Gong, Jianhua and McGuire, Jeffrey J.}
}
@article {rychert_dynamic_2021,
	title = {A dynamic lithosphere{\textendash}asthenosphere boundary near the equatorial Mid-Atlantic Ridge},
	journal = {Earth and Planetary Science Letters},
	volume = {566},
	year = {2021},
	month = {07/2021},
	pages = {116949},
	abstract = {In plate tectonic theory a weak asthenosphere is required to facilitate the motions of the rigid plates. Partial melt could weaken the mantle, in turn impacting convection, but to date the existence of persistent melt has remained controversial. A wide range of scenarios has been reported in terms of the location, amount and pathways of melt. Here we use data collected by 39 ocean bottom seismometers deployed near the equatorial Mid-Atlantic Ridge on 0 to 80 Myr old seafloor. We calculate S-to-P (Sp) receiver functions and perform waveform modeling. We jointly interpret with shear-wave velocity tomography from surface waves and magnetotelluric (MT) imaging to take advantage of a range of resolutions and sensitivities and illuminate the structure of the oceanic lithosphere and the underlying asthenosphere. We image a tectonic plate thickness that increases with age in one location but undulates in another location. We infer thin and slightly thicker melt channels and punctuated regions of ascending partial melt several hundred kilometers off the ridge axis. This suggests melt persists over geologic timescales, although its character is dynamic, with implications for the lithosphere{\textendash}asthenosphere boundary (LAB) and the driving forces of the plates. Ascending melt intermittently feeds melt channels at the base of the plate. The associated melt-enhanced buoyancy increases the influence of ridge-push in driving plate motions, whereas the channelized melt reduces the resistance of the plates to motion. Therefore, melt dynamics may play a larger role in controlling plate tectonics than previously thought.},
	keywords = {melt dynamics, Mid-Atlantic Ridge, oceanic lithosphere{\textendash}asthenosphere boundary, Plate tectonics, receiver functions, seismology},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2021.116949},
	url = {https://www.sciencedirect.com/science/article/pii/S0012821X21002089},
	author = {Rychert, Catherine A. and Tharimena, Saikiran and Harmon, Nicholas and Wang, Shunguo and Constable, Steven and Kendall, J. Michael and Bogiatzis, Petros and Agius, Matthew R. and Schlaphorst, David}
}
@article {dobashi_improving_2021,
	title = {Improving Detectability of Seafloor Deformation From Bottom Pressure Observations Using Numerical Ocean Models},
	journal = {Frontiers in Earth Science},
	volume = {8},
	year = {2021},
	month = {01/2021},
	abstract = {We investigated ocean bottom pressure (OBP) observation data at six plate subduction zones around the Pacific Ocean. The six regions included the Hikurangi Trough, the Nankai Trough, the Japan Trench, the Aleutian Trench, the Cascadia Subduction Zone, and the Chile Trench. For the sake of improving the detectability of seafloor deformation using OBP observations, we used numerical ocean models to represent realistic oceanic variations, and subtracted them from the observed OBP data. The numerical ocean models included four ocean general circulation models (OGCMs) of HYCOM, GLORYS, ECCO2, and JCOPE2M, and a single-layer ocean model (SOM). The OGCMs are mainly driven by the wind forcing. The SOM is driven by wind and/or atmospheric pressure loading. The modeled OBP was subtracted from the observed OBP data, and root-mean-square (RMS) amplitudes of the residual OBP variations at a period of 3{\textendash}90~days were evaluated by the respective regions and by the respective numerical ocean models. The OGCMs and SOM driven by wind alone (SOMw) contributed to 5{\textendash}27\% RMS reduction in the residual OBP. When SOM driven by atmospheric pressure alone (SOMp) was added to the modeled OBP, residual RMS amplitudes were additionally reduced by 2{\textendash}15\%. This indicates that the atmospheric pressure is necessary to explain substantial amounts of observed OBP variations at the period. The residual RMS amplitudes were 1.0{\textendash}1.7~hPa when SOMp was added. The RMS reduction was relatively effective as 16{\textendash}42\% at the Hikurangi Trough, the Nankai Trough, and the Japan Trench. The residual RMS amplitudes were relatively small as 1.0{\textendash}1.1~hPa at the Nankai Trough and the Chile Trench. These results were discussed with previous studies that had identified slow slips using OBP observations. We discussed on further accurate OBP modeling, and on improving detectability of seafloor deformation using OBP observation arrays.},
	issn = {2296-6463},
	doi = {10.3389/feart.2020.598270},
	url = {https://www.frontiersin.org/articles/10.3389/feart.2020.598270},
	author = {Dobashi, Yoichiro and Inazu, Daisuke}
}
@article {zhang_isotropic_2021,
	title = {Isotropic and azimuthally anisotropic Rayleigh wave dispersion across the Juan de Fuca and Gorda plates and U.S. Cascadia from earthquake data and ambient noise two- and three-station interferometry},
	journal = {Geophysical Journal International},
	volume = {226},
	number = {2},
	year = {2021},
	pages = {862{\textendash}883},
	abstract = {We use data from the Cascadia Initiative (CI) amphibious array and the USArray Transportable Array to construct and compare Rayleigh wave isotropic and azimuthally anisotropic phase speed maps across the Juan de Fuca and Gorda Plates extending onto the continental northwestern United States. Results from both earthquakes (28{\textendash}80~s) as well as ambient noise two- and three-station interferometry (10{\textendash}40~s) are produced. Compared with two-station interferometry, three-station direct wave interferometry provides \&gt;50~per~cent improvement in the signal-to-noise ratio and the number of dispersion measurements obtained, particularly in the noisier oceanic environment. Earthquake and ambient noise results are complementary in bandwidth and azimuthal coverage, and agree within about twice the estimated uncertainties of each method. We, therefore, combine measurements from the different methods to produce composite results that provide an improved data set in accuracy, resolution and spatial and azimuthal coverage over each individual method. A great variety of both isotropic and azimuthally anisotropic structures are resolved. Across the oceanic plate, fast directions of anisotropy with 180{\textdegree} periodicity (2ψ) generally align with palaeo-spreading directions while 2ψ amplitudes mostly increase with lithospheric age, both displaying substantial variations with depth and age. Strong (\&gt;3~per~cent) apparent anisotropy with 360{\textdegree} periodicity (1ψ) is observed at long periods (\&gt;50~s) surrounding the Cascade Range, probably caused by backscattering from heterogeneous isotropic structures.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggab142},
	url = {https://doi.org/10.1093/gji/ggab142},
	author = {Zhang, Shane and Wang, Hongda and Wu, Mengyu and Ritzwoller, Michael H}
}
@article {russell_lithosphere_2021,
	title = {Lithosphere Structure and Seismic Anisotropy Offshore Eastern North America: Implications for Continental Breakup and Ultra-Slow Spreading Dynamics},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {126},
	number = {12},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2021JB022955},
	month = {11/2021},
	pages = {e2021JB022955},
	abstract = {The breakup of supercontinent Pangea occurred \~{}200 Ma forming the Eastern North American Margin (ENAM). Yet, the precise timing and mechanics of breakup and onset of seafloor spreading remain poorly constrained. We investigate the relict lithosphere offshore eastern North America using ambient-noise Rayleigh-wave phase velocity (12{\textendash}32 s) and azimuthal anisotropy (17{\textendash}32 s) at the ENAM Community Seismic Experiment (CSE). Incorporating previous constraints on crustal structure, we construct a shear velocity model for the crust and upper \~{}60 km of the mantle beneath the ENAM-CSE. A low-velocity lid (VS of 4.4{\textendash}4.55 km/s) is revealed in the upper 15{\textendash}20 km of the mantle that extends \~{}200 km from the margin, terminating at the Blake Spur Magnetic Anomaly (BSMA). East of the BSMA, velocities are fast (>4.6 km/s) and characteristic of typical oceanic mantle lithosphere. We interpret the low-velocity lid as stretched continental mantle lithosphere embedded with up to \~{}15\% retained gabbro. This implies that the BSMA marks successful breakup and onset of seafloor spreading \~{}170 Ma, consistent with ENAM-CSE active-source studies that argue for breakup \~{}25 Myr later than previously thought. We observe margin-parallel Rayleigh-wave azimuthal anisotropy (2\%{\textendash}4\% peak-to-peak) in the lithosphere that approximately correlates with absolute plate motion (APM) at the time of spreading. We hypothesize that lithosphere formed during ultra-slow seafloor spreading records APM-modified olivine fabric rather than spreading-parallel fabric typical of higher spreading rates. This work highlights the importance of present-day passive margins for improving understanding of the fundamental rift-to-drift transition.},
	keywords = {ambient noise, continental rifting, eastern North American margin, oceanic lithosphere, seismic anisotropy, surface-wave tomography},
	issn = {2169-9356},
	doi = {10.1029/2021JB022955},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021JB022955},
	author = {Russell, J. B. and Gaherty, J. B.}
}
@article {brunsvik_mantle_2021,
	title = {Mantle Structure and Flow Across the Continent-Ocean Transition of the Eastern North American Margin: Anisotropic S-Wave Tomography},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {22},
	number = {12},
	year = {2021},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2021GC010084},
	pages = {e2021GC010084},
	abstract = {Little has been seismically imaged through the lithosphere and mantle at rifted margins across the continent-ocean transition. A 2014{\textendash}2015 community seismic experiment deployed broadband seismic instruments across the shoreline of the eastern North American rifted margin. Previous shear-wave splitting along the margin shows several perplexing patterns of anisotropy, and by proxy, mantle flow. Neither margin parallel offshore fast azimuths nor null splitting on the continental coast obviously accord with absolute plate motion, paleo-spreading, or rift-induced anisotropy. Splitting measurements, however, offer no depth constraints on anisotropy. Additionally, mantle structure has not yet been imaged in detail across the continent-ocean transition. We used teleseismic S, SKS, SKKS, and PKS splitting and differential travel times recorded on ocean-bottom seismometers, regional seismic networks, and EarthScope Transportable Array stations to conduct joint isotropic/anisotropic tomography across the margin. The velocity model reveals a transition from fast, thick, continental keel to low velocity, thinned lithosphere eastward. Imaged short wavelength velocity anomalies can be largely explained by edge-driven convection or shear-driven upwelling. We also find that layered anisotropy is prevalent across the margin. The anisotropic fast polarization is parallel to the margin within the asthenosphere. This suggests margin parallel flow beneath the plate. The lower oceanic lithosphere preserves paleo-spreading-parallel anisotropy, while the continental lithosphere has complex anisotropy reflecting several Wilson cycles. These results demonstrate the complex and active nature of a margin which is traditionally considered tectonically inactive.},
	keywords = {anisotropy, continent-ocean transition, eastern North American margin, shear wave splitting, tomography},
	issn = {1525-2027},
	doi = {10.1029/2021GC010084},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021GC010084},
	author = {Brunsvik, Brennan R. and Eilon, Zachary C. and Lynner, Colton}
}
@article {doran_melt-affected_2021,
	title = {Melt-affected ocean crust and uppermost mantle near Hawaii{\textemdash}clues from ambient-noise phase velocity and seafloor compliance},
	journal = {Geophysical Journal International},
	volume = {224},
	number = {2},
	year = {2021},
	month = {jan},
	pages = {843{\textendash}857},
	abstract = {We present models of crustal and uppermost mantle structure beneath the Hawaiian Swell and surrounding region. The models were derived from ambient-noise intermediate-period Rayleigh-wave phase velocities and from seafloor compliance that were estimated from continuous seismic and pressure recordings collected during the Hawaiian Plume-Lithosphere Undersea Mantle Experiment (PLUME). We jointly inverted these data at the locations of over 50 ocean-bottom instruments, after accounting for variations in local bathymetry and sediment properties. Our results suggest that the crystalline crust is up to 15~km thick beneath the swell and up to 23~km thick closer to the islands. Anomalously thick crust extends towards the older seamounts, downstream of Hawaii. In a second region, anomalies immediately to the south of Hawaii may be associated with the leading edge of the shallow Hawaiian magma conduit. In a third region, thickened crust to the immediate west of Hawaii may be related to Cretaceous seamounts. Low seismic velocities identified in the uppermost mantle to the northeast of Hawaii may be linked to the Molokai fracture zone and may be manifest of complex non-vertical pathways of melt through the upper lithosphere. Velocity anomalies decrease in amplitude towards the surface, suggesting that melt becomes focused into conduits at depths between 20 and 40~km that escape the resolution capabilities of our data set.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggaa470},
	url = {https://doi.org/10.1093/gji/ggaa470},
	author = {Doran, A K and Laske, G}
}
@article {wilcock_method_2021,
	title = {A method for tracking blue whales (Balaenoptera musculus) with a widely spaced network of ocean bottom seismometers},
	journal = {PLOS ONE},
	volume = {16},
	number = {12},
	year = {2021},
	note = {Publisher: Public Library of Science},
	month = {dec},
	pages = {e0260273},
	abstract = {Passive acoustic monitoring is an important tool for studying marine mammals. Ocean bottom seismometer networks provide data sets of opportunity for studying blue whales (Balaenoptera musculus) which vocalize extensively at seismic frequencies. We describe methods to localize calls and obtain tracks using the B call of northeast Pacific blue whale recorded by a large network of widely spaced ocean bottom seismometers off the coast of the Pacific Northwest. The first harmonic of the B call at \textasciitilde15 Hz is detected using spectrogram cross-correlation. The seasonality of calls, inferred from a dataset of calls identified by an analyst, is used to estimate the probability that detections are true positives as a function of the strength of the detection. Because the spacing of seismometers reaches 70 km, faint detections with a significant probability of being false positives must be considered in multi-station localizations. Calls are located by maximizing a likelihood function which considers each strong detection in turn as the earliest arrival time and seeks to fit the times of detections that follow within a feasible time and distance window. An alternative procedure seeks solutions based on the detections that maximize their sum after weighting by detection strength and proximity. Both approaches lead to many spurious solutions that can mix detections from different B calls and include false detections including misidentified A calls. Tracks that are reliable can be obtained iteratively by assigning detections to localizations that are grouped in space and time, and requiring groups of at least 20 locations. Smooth paths are fit to tracks by including constraints that minimize changes in speed and direction while fitting the locations to their uncertainties or applying the double difference relocation method. The reliability of localizations for future experiments might be improved by increasing sampling rates and detecting harmonics of the B call.},
	keywords = {Blue whales, Fin whales, Latitude, Longitude, Marine mammals, Oceans, Probability density, Whales},
	issn = {1932-6203},
	doi = {10.1371/journal.pone.0260273},
	url = {https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0260273},
	author = {Wilcock, William S. D. and Hilmo, Rose S.}
}
@article {li_modification_2021,
	title = {Modification of Crust and Mantle Lithosphere Beneath the Southern Part of the Eastern North American Passive Margin},
	journal = {Geophysical Research Letters},
	volume = {48},
	number = {16},
	year = {2021},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2020GL090555},
	pages = {e2020GL090555},
	abstract = {The eastern North American passive margin was modified by Mesozoic rifting. Seismic data from recent deployment of onshore and offshore stations offer a unique opportunity for studying the signature of syn-rifting and postrifting in lithospheric structures. Using full-wave ambient noise tomography, we construct a new seismic velocity model for the lithosphere of the southeastern United States. Our model confirms an oceanic-continental transitional crust over a \~{}70 km wide zone across the coastline. Our model reveals (a) a patch of lower-than-average mantle lithospheric velocities underlying this transitional crust and (b) a low-velocity column in the mantle lithosphere beneath the Virginia volcanoes. We propose that anomaly 1 represents cooled enriched mantle that underplated the thinning crust during the initial stages of rifting around 230 Ma. Anomaly 2 likely has a more recent origin in the Eocene and may result from an asthenospheric upwelling induced by a localized lithospheric delamination.},
	keywords = {full-wave ambient noise tomography, lithospheric structure, the eastern North American passive margin},
	issn = {1944-8007},
	doi = {10.1029/2020GL090555},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020GL090555},
	author = {Li, Cong and Gao, Haiying}
}
@article {nakai_near_2021,
	title = {Near Trench 3D Seismic Attenuation Offshore Northern Hikurangi Subduction Margin, North Island, New Zealand},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {126},
	number = {3},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020JB020810},
	month = {02/2021},
	pages = {e2020JB020810},
	abstract = {We image seismic attenuation near the Hikurangi trench offshore New Zealand, using ocean bottom and land-based seismometers, revealing high attenuation above a recurring shallow slow-slip event and within the subducting Hikurangi Plateau. The Hikurangi subduction margin east of the North Island, New Zealand is the site of frequent shallow slow slip events. Overpressured fluids are hypothesized to lead to slow slip at shallow depths close to the oceanic trench. Seismic attenuation, energy loss of seismic waves, can be used to detect high temperatures, melt, the presence of fluids, and fractures. We use local earthquake P- and S-waves from 180 earthquakes to invert for t*, and subsequently invert for Qp and Qs, offshore the North Island directly above the area of slow slip. We image Qp and Qs to \~{}25 km depth, increasing resolution of previously identified coastal low Q (100{\textendash}300), and finding a new region of even higher attenuation (Qp and Qs < 50{\textendash}100) directly above the shallow slow slip event of 2014{\textendash}2015, beneath the offshore seismic array. This highest attenuation is downdip of a subducting seamount, and is spatially correlated with a high seismic reflectivity zone and Vp/Vs > 1.85, all of which provide evidence for the presence of fluids. The Qp and Qs is low at the trench (<50{\textendash}100) and in the subducting plate (100{\textendash}200), suggesting that seismic wave scattering due to faults, fractures, and the inherent heterogeneous composition of the Hikurangi Plateau, a large igneous province, plays a role in seismic attenuation.},
	keywords = {fluids, seismic attenuation, subduction zone},
	issn = {2169-9356},
	doi = {10.1029/2020JB020810},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020JB020810},
	author = {Nakai, Jenny S. and Sheehan, Anne F. and Abercrombie, Rachel E. and Eberhart-Phillips, Donna}
}
@article {laske_observations_2021,
	title = {Observations of Earth{\textquoteright}s Normal Modes on Broadband Ocean Bottom Seismometers},
	journal = {Frontiers in Earth Science},
	volume = {9},
	year = {2021},
	month = {06/2021},
	abstract = {It is generally thought that high noise levels in the oceans inhibit the observation of long-period earthquake signals such as Earth{\textquoteright}s normal modes on ocean bottom seismometers (OBSs). Here, we document the observation of Earth{\textquoteright}s gravest modes at periods longer than 500~s (or frequencies below 2~mHz). We start with our own 2005{\textendash}2007 Plume-Lithosphere-Undersea-Mantle Experiment (PLUME) near Hawaii that deployed a large number of broadband OBSs for the first time. We collected high-quality normal mode spectra for the great November 15, 2006 Kuril Islands earthquake on multiple OBSs. The random deployment of instruments from different OBS groups allows a direct comparison between different broadband seismometers. For this event, mode S06 (1.038~mHz) consistently rises above the background noise at all OBSs that had a Nanometrics Trillium T-240 broadband seismometer. We also report observations of other deployments in the Pacific ocean that involved instruments of the U.S. OBS Instrument Pool (OBSIP) where we observe even mode S04 (0.647~mHz). Earth{\textquoteright}s normal modes were never the initial target of any OBS deployment, nor was any other ultra-low-frequency signal. However, given the high costs of an OBS campaign, the fact that data are openly available to future investigators not involved in the campaign, and the fact that seismology is evolving to investigate ever-new signals, this paper makes the case that the investment in a high-quality seismic sensor may be a wise one, even for a free-fall OBS.},
	issn = {2296-6463},
	doi = {10.3389/feart.2021.679958},
	url = {https://www.frontiersin.org/articles/10.3389/feart.2021.679958},
	author = {Laske, Gabi}
}
@article {eilon_pacific_2021,
	title = {The Pacific OBS Research into Convecting Asthenosphere (ORCA) Experiment},
	journal = {Seismological Research Letters},
	volume = {93},
	number = {1},
	year = {2021},
	month = {01/2022},
	pages = {477{\textendash}493},
	abstract = {The Pacific ocean-bottom seismometer (OBS) Research into Convecting Asthenosphere (ORCA) experiment deployed two 30-station seismic arrays between 2018 and 2020{\textemdash}a US contribution to the international PacificArray project. The {\textquotedblleft}Young ORCA{\textquotedblright} array deployed on \~{}40~Ma central Pacific seafloor had a \~{}68\% data recovery rate, whereas the {\textquotedblleft}Old ORCA{\textquotedblright} array deployed on \~{}120~Ma southwest Pacific seafloor had a \~{}80\% recovery rate. We detail here the seismic data quality, spectral characteristics, and engineering challenges of this experiment. We provide information to assist users of this dataset, including OBS orientations and tables of daily data quality for all channels. Preliminary analysis illustrates the utility of these data for surface- and body-wave seismic imaging.},
	issn = {0895-0695},
	doi = {10.1785/0220210173},
	url = {https://doi.org/10.1785/0220210173},
	author = {Eilon, Zachary C. and Gaherty, James B. and Zhang, Lun and Russell, Joshua and McPeak, Sean and Phillips, Joseph and Forsyth, Donald W. and Ekstr{\"o}m, G{\"o}ran}
}
@article {alongi_probing_2021,
	title = {Probing the Southern Cascadia Plate Interface With the Dense Amphibious Cascadia Initiative Seismic Array},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {126},
	number = {7},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2021JB022180},
	month = {06/2021},
	pages = {e2021JB022180},
	abstract = {Fault coupling is vital in determining the amount of strain that is accumulated along faults. The magnitude and location of stored elastic strain energy in highly coupled regions has important implications for understanding the full range of slip behavior at plate boundary faults, as well as earthquake and tsunami hazards. We use the temporary dense amphibious array of seismometers offered by the Cascadia Initiative to create a high-resolution catalog of events to examine the spatio-temporal behavior of earthquakes near the plate interface. The data show that in southern Cascadia the plate interface updip of the geodetically locked region is nearly devoid of seismicity, therefore likely highly coupled and accumulating strain. The catalog reveals events that are clustered at the downdip edge of the highly coupled megathrust that correlate in time with nearby strain transient observations. Template matching of events in the cluster using permanent stations of the Northern California Seismic Network over a 10-year period between 2010 and 2020 indicates that this cluster is unique in space and time. Its activity only during the strain transient provides support for the utility of seismic observations in the identification of strain transients.},
	keywords = {microseismicity, ocean bottom seismometers, plate interface, seismology, strain transient, template matching},
	issn = {2169-9356},
	doi = {10.1029/2021JB022180},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021JB022180},
	author = {Alongi, T. and Schwartz, S. Y. and Shaddox, H. R. and Small, D. T.}
}
@article {heath_relationship_2021,
	title = {Relationship Between Active Faulting/Fracturing and Magmatism Around Santorini: Seismic Anisotropy From an Active Source Tomography Experiment},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {126},
	number = {8},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2021JB021898},
	month = {07/2021},
	pages = {e2021JB021898},
	abstract = {In extending volcanic arcs such as the Aegean, tectonic processes exert a significant control on magmatism. Spanning scales from 1 to 10s of km, volcanic vents, edifices, and eruptive centers follow the orientation of, and are located near, fault zones. Whether this tectonic control on magmatism results from individual faults/fractures weakening the crust or because regional stresses control magma input into the crust is debated. Here we investigate the scales of tectonic and magmatic interactions, specifically focusing on the role of local-scale (<10 km) faults/fractures in controlling magmatism. We infer local-scale fault/fracture orientations from anisotropic active-source P-wave travel-time tomography to investigate tectonic and magmatic interactions in the upper crust of Santorini Volcano, Greece, and the actively deforming region to the east. We use the anisotropy magnitude and seismic velocity reduction to model the relative distribution of both consistently oriented and randomly oriented faults/fractures. Our results show that oriented faulting/fracturing resulting from regional-scale (>10 km) tectonic stresses is distributed broadly across the region at 2{\textendash}3 km depth, approximately paralleling volcanic/magmatic features. On a local-scale, magmatism is neither localized in areas of higher oriented fault/fracture density, nor is it accommodating enough extensional strain to inhibit oriented faulting/fracturing of host rock. The alignment of magmatic features shows strong tectonic control despite the lack of correlation with local oriented fault/fracture density. These results suggest that magmatic processes are strongly influenced by regional-scale, not local-scale, tectonic processes. We infer regional processes have a greater impact on magmatism than local features due to their greater effect at depth.},
	keywords = {anisotropy, faulting, magmatism, seismology, tectonism, tectono-magmatism},
	issn = {2169-9356},
	doi = {10.1029/2021JB021898},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021JB021898},
	author = {Heath, B. A. and Hooft, E. E. E. and Toomey, D. R. and Paulatto, M. and Papazachos, C. B. and Nomikou, P. and Morgan, J. V.}
}
@article {saikia_seismic_2021,
	title = {Seismic Attenuation at the Equatorial Mid-Atlantic Ridge Constrained by Local Rayleigh Wave Analysis From the PI-LAB Experiment},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {22},
	number = {12},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2021GC010085},
	month = {12/2021},
	pages = {e2021GC010085},
	abstract = {The ocean lithosphere represents a simple realisation of the tectonic plate, offering a unique opportunity to better understand its physical and chemical properties in relationship to those of the underlying asthenosphere. While seismic velocity is frequently used to image the plate, seismic attenuation (Qμ-1) offers an important complimentary observation. We use fundamental mode Rayleigh waves from 17 local, M > 4.2 earthquakes recorded at stations located on 0{\textendash}80 My old lithosphere near the equatorial Mid-Atlantic Ridge. We determine the attenuation coefficient () for periods between 15 and 40 s and invert for 1-D average shear wave quality factor values () and shear wave velocity (Vs). We find values of 175 {\textpm} 16 at 50 km depth, decreasing to 90 {\textpm} 15 at greater than 60 km. Comparison of our and Vs measurements to previous observations from oceanic settings shows agreement in terms of higher and Vs in the lithosphere in comparison to the asthenosphere. The observations from oceanic settings are in general agreement with the laboratory predictions for -Vs relationships for thermal models. However, a small amount of partial melt (1\%) is required to explain several previous observations. Our result also compares favorably to previous observations of lithospheric and asthenospheric attenuation with respect to frequency. Melt is not required for the 1-D average of our study area, consistent with previous electromagnetic and seismic imaging that suggested melt in punctuated and/or thin channel anomalies rather than over broad regions of the mantle.},
	keywords = {attenuation, Mid Atlantic Ridge, surface wave},
	issn = {1525-2027},
	doi = {10.1029/2021GC010085},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021GC010085},
	author = {Saikia, Utpal and Rychert, Catherine A. and Harmon, Nicholas and Michael Kendall, J.}
}
@article {kuna_seismic_2021,
	title = {Seismic crustal imaging using fin whale songs},
	journal = {Science},
	volume = {371},
	number = {6530},
	year = {2021},
	note = {Publisher: American Association for the Advancement of Science},
	month = {02/2021},
	pages = {731{\textendash}735},
	abstract = {Fin whale calls are among the strongest animal vocalizations that are detectable over great distances in the oceans. We analyze fin whale songs recorded at ocean-bottom seismometers in the northeast Pacific Ocean and show that in addition to the waterborne signal, the song recordings also contain signals reflected and refracted from crustal interfaces beneath the stations. With these data, we constrain the thickness and seismic velocity of the oceanic sediment and basaltic basement and the P-wave velocity of the gabbroic lower crust beneath and around the ocean bottom seismic stations. The abundant and globally available fin whale calls may be used to complement seismic studies in situations where conventional air-gun surveys are not available.},
	doi = {10.1126/science.abf3962},
	url = {https://www.science.org/doi/10.1126/science.abf3962},
	author = {Kuna, V{\'a}clav M. and N{\'a}b{\v e}lek, John L.}
}
@article {watts_seismic_2021,
	title = {Seismic Structure, Gravity Anomalies and Flexure Along the Emperor Seamount Chain},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {126},
	number = {3},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020JB021109},
	month = {02/2021},
	pages = {e2020JB021109},
	abstract = {The Hawaiian-Emperor seamount chain in the Pacific Ocean has provided fundamental insights into hotspot generated intraplate volcanism and the long-term strength of oceanic lithosphere. However, only a few seismic experiments to determine crustal and upper mantle structure have been carried out on the Hawaiian Ridge, and no deep imaging has ever been carried out along the Emperor seamounts. Here, we present the results of an active source seismic experiment using 29 Ocean-Bottom Seismometers (OBS) carried out along a strike profile of the seamounts in the region of Jimmu and Suiko guyots. Joint reflection and refraction tomographic inversion of the OBS data show the upper crust is highly heterogeneous with P wave velocities <4{\textendash}5 km s-1, which are attributed to extrusive lavas and clastics. In contrast, the lower crust is remarkably homogeneous with velocities of 6.5{\textendash}7.2 km s-1, which we attribute to oceanic crust and mafic intrusions. Moho is identified by a strong PmP arrival at offsets of 20{\textendash}80 km, yielding depths of 13{\textendash}16 km. The underlying mantle is generally homogeneous with velocities in the range 7.9{\textendash}8.0 km s-1. The crust and mantle velocity structure has been verified by gravity modeling. While top of oceanic crust prior to volcano loading is not recognized as a seismic or gravity discontinuity, flexural modeling reveals a \~{}5.0{\textendash}5.5 km thick preexisting oceanic crust that is overlain by a \~{}8 km thick volcanic edifice. Unlike at the Hawaiian Ridge, we find no evidence of magmatic underplating.},
	keywords = {gravity and isostasy, marine geology \& geophysics, marine seismics, oceanic hotspots and intraplate volcanism, seafloor morphology},
	issn = {2169-9356},
	doi = {10.1029/2020JB021109},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020JB021109},
	author = {Watts, A. B. and Grevemeyer, I. and Shillington, D. J. and Dunn, R. A. and Boston, B. and G{\'o}mez de la Pe{\~n}a, L.}
}
@article {harmon_shear_2021,
	title = {Shear Velocity Inversion Guided by Resistivity Structure From the PI-LAB Experiment for Integrated Estimates of Partial Melt in the Mantle},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {126},
	number = {8},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2021JB022202},
	month = {08/2021},
	pages = {e2021JB022202},
	abstract = {The lithosphere-asthenosphere system is fundamental to our understanding of mantle convection and plate tectonics. The different sensitivities of seismic and electromagnetic methods can be used together to better constrain the properties of the system. Here, we re-examine the shear velocity model from Rayleigh waves in light of the magnetotelluric based resistivity models from the Passive Imaging of the Lithosphere Asthenosphere Boundary (PI-LAB) experiment near the equatorial Mid-Atlantic Ridge, with the goal of generating a structurally consistent velocity and resistivity model for the region. Cross-plots of the models suggest a linear or near-linear trend that is also in agreement with petrophysical predictions. We generate a new shear velocity model from the resistivity models based on petrophysical relationships. The new velocity model fits the phase velocity data, and the correlation coefficient between the shear velocity and resistivity models is increased. Much of the model can be predicted by expectations for a thermal half-space cooling model, although some regions require a combination of higher temperatures, volatiles, or partial melt. We use the petrophysical predictions to estimate the melt fraction, melt volatile content, and temperature structure of the asthenospheric anomalies. We find up to 4\% melt, with the lowest resistivities and shear velocities explained by up to 20\% water or 20\% CO2 in the melt or \~{}1\% nearly pure sulfide melt, depending on the set of assumptions used. Melt is required in punctuated anomalies over broad depth ranges, and also in channels at the base of the lithosphere. Melt in the asthenosphere is dynamic, yet persistent on geologic timescales.},
	keywords = {lithosphere asthenosphere, magnetotellurics, melt, Mid-Atlantic Ridge, Rayleigh wave tomography, small-scale convection},
	issn = {2169-9356},
	doi = {10.1029/2021JB022202},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021JB022202},
	author = {Harmon, Nicholas and Wang, Shunguo and Rychert, Catherine A. and Constable, Steven and Kendall, J. Michael}
}
@article {zhang_signature_2021,
	title = {The Signature and Elimination of Sediment Reverberations on Submarine Receiver Functions},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {126},
	number = {5},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020JB021567},
	pages = {e2020JB021567},
	abstract = {While the receiver function technique has been successfully applied to high-resolution imaging of sharp discontinuities within and across the lithosphere, it suffers from severe limitations when applied to seafloor seismic recordings. This is because the water and sediment layer could strongly influence the receiver function traces, making detection and interpretation of crust and mantle layering difficult. This effect is often referred to as the singing phenomena in marine environments. We demonstrate, using analytical and synthetic modeling, that this singing effect can be reversed using a selective dereverberation filter tuned to match the elastic property of each layer. We apply the dereverberation filter to high-quality earthquake records collected from the NoMelt seismic array deployed on normal, mature Pacific seafloor. An appropriate filter designed using the elastic properties of the underlying sediments, obtained from prior studies, greatly improves the detection of Ps conversions from the Moho (\~{}8.6 km) and from a sharp discontinuity (<\~{}5 km) across the lithosphere asthenosphere transition (\~{}72 km). Sensitivity tests show that the dereverberation filter is mostly sensitive to the two-way travel time of the shear wave in sediment and is robust to seismic noise and small errors in the sediment properties. Our analysis suggests that selectively filtering out the sediment reverberations from ocean seismic data could make inferences on subsurface structure more robust. We expect that this study will enable high-resolution receiver function imaging of the oceanic plate across the growing ocean bottom seismic arrays being deployed in the global oceans.},
	issn = {2169-9356},
	doi = {10.1029/2020JB021567},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020JB021567},
	author = {Zhang, Ziqi and Olugboji, Tolulope}
}
@article {agius_thin_2021,
	title = {A thin mantle transition zone beneath the equatorial Mid-Atlantic Ridge},
	journal = {Nature},
	volume = {589},
	number = {7843},
	year = {2021},
	note = {Publisher: Nature Publishing Group},
	month = {01/2021},
	pages = {562{\textendash}566},
	abstract = {The location and degree of material transfer between the upper and lower mantle are key to the Earth{\textquoteright}s thermal and chemical evolution. Sinking slabs and rising plumes are generally accepted as locations of transfer1,2, whereas mid-ocean ridges are not typically assumed to have a role3. However, tight constraints from in situ measurements at ridges have proved to be challenging. Here we use receiver functions that reveal the conversion of primary to secondary seismic waves to image the discontinuities that bound the mantle transition zone, using ocean bottom seismic data from the equatorial Mid-Atlantic Ridge. Our images show that the seismic discontinuity at depths of~about 660~kilometres is broadly uplifted by 10~{\textpm}~4 kilometres over a swath about 600~kilometres wide and that the 410-kilometre discontinuity is depressed by 5~{\textpm}~4~kilometres. This thinning of the mantle transition zone is coincident with slow shear-wave velocities in the mantle, from global seismic tomography4{\textendash}7. In addition, seismic velocities in the mantle transition zone beneath the Mid-Atlantic Ridge are on average slower than those beneath older Atlantic Ocean seafloor. The observations imply material transfer from the lower to the upper mantle{\textemdash}either continuous or punctuated{\textemdash}that is linked to the Mid-Atlantic Ridge. Given the length and longevity of the mid-ocean ridge system, this implies that whole-mantle convection may be more prevalent than previously thought, with ridge upwellings having a role in counterbalancing slab downwellings.},
	keywords = {Geodynamics, Geophysics, seismology},
	issn = {1476-4687},
	doi = {10.1038/s41586-020-03139-x},
	url = {https://www.nature.com/articles/s41586-020-03139-x},
	author = {Agius, Matthew R. and Rychert, Catherine A. and Harmon, Nicholas and Tharimena, Saikiran and Kendall, J.-Michael}
}
@article {leptokaropoulos_tidal_2021,
	title = {Tidal Triggering of Microseismicity at the Equatorial Mid-Atlantic Ridge, Inferred From the PI-LAB Experiment},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {126},
	number = {9},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2021JB022251},
	month = {08/2021},
	pages = {e2021JB022251},
	abstract = {The gravitational pulls from the moon and the sun result in tidal forces which influence both Earth{\textquoteright}s solid and water mass. These stresses are periodically added to the tectonic ones and may become sufficient for initiating rupture in fault systems critically close to failure. Previous research indicates correlations between increased seismicity rates and low tides for fast- and intermediate-spreading mid-ocean ridges in the Pacific Ocean. Here, we present a microseismicity data set (4,719 events) recorded by an ocean bottom seismometer deployment at the equatorial Mid-Atlantic Ridge. We show that low, as well as decreasing ocean water level, result in relatively elevated seismicity rates at higher magnitudes (lower b-values), translated into increased probabilities of stronger event occurrence at or towards low tides. Moreover, seismic bursts (enhanced activity rate clusters), occurring at rates well above the reference seismicity, are exclusively present during values of either high tidally induced extensional stresses or high extensional stress rates. Although the b-value differences are not significant enough to be conclusive, the seismicity rate variations exhibit statistical significance, supporting the previous findings for tidal triggering at low tides within normal-faulting regimes and extending the range of observations to slow-spreading ridges. Observed triggering of slip on low angle faults at low tides is predicted by Coulomb stress modeling. The triggering of slip on high angle faults observed here, is not easily explained without another factor. It may be related to the presence of a shallow magma body beneath the ridge, as supported by previous seismic imaging in the region.},
	keywords = {b-values, Coulomb stress, magnitude distribution, Mid-Atlantic Ridge, seismicity, tidal triggering},
	issn = {2169-9356},
	doi = {10.1029/2021JB022251},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021JB022251},
	author = {Leptokaropoulos, K. and Harmon, N. and Hicks, S. P. and Rychert, C. A. and Schlaphorst, D. and Kendall, J. M.}
}
@article {saikia_upper_2021,
	title = {Upper Mantle Anisotropic Shear Velocity Structure at the Equatorial Mid-Atlantic Ridge Constrained by Rayleigh Wave Group Velocity Analysis From the PI-LAB Experiment},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {22},
	number = {3},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020GC009495},
	month = {02/2021},
	pages = {e2020GC009495},
	abstract = {The evolution of ocean lithosphere and asthenosphere are fundamental to plate tectonics, yet high resolution imaging is rare. We present shear wave velocity and azimuthal anisotropy models for the upper mantle from Rayleigh wave group velocities from local earthquake and ambient noise at 15{\textendash}40-s period recorded by the Passive Imaging of the Lithosphere Asthenosphere Boundary experiment at the equatorial Mid-Atlantic Ridge covering 0{\textendash}80-Myr-old seafloor. We find slow velocities along the ridge, with faster velocities beneath older seafloor. We image a fast lid (25{\textendash}30-km thick) beneath the ridge that increases to 50{\textendash}60 km beneath older seafloor. Punctuated, \~{}100 km wide low velocity anomalies exist off-axis. There are multiple layers of azimuthal anisotropy, including (i) a lithosphere (20{\textendash}40 km depth) characterized by strong anisotropy (4.0\%{\textendash}7.0 \%) with fast-axes that rotate from ridge subparallel toward the absolute plate motion/spreading direction at distances >60 km from the ridge, and (ii) weak anisotropy (1.0\%{\textendash}2.0\%) at >40 km depth. Our results are consistent with conductive cooling of lithosphere, although with some complexities. Thickened lithosphere beneath the ridge supports lateral conductive cooling beneath slow-spreading centers. Undulations in lithospheric thickness and slow asthenospheric velocities are consistent with small scale convection and/or partial melt. Lithospheric anisotropy can be explained by vertical flow and a contribution from either fluid or mineral filled cracks organized melt beneath the ridge and plate motion induced strain off axis. Deep azimuthal anisotropy is suggestive of upwelling beneath the ridge and three-dimensional flow possibly caused by small scale convection off-axis.},
	keywords = {asthenosphere, azimuthal anisotropy, Lithosphere, Mid-Atlantic Ridge, shear wave velocity},
	issn = {1525-2027},
	doi = {10.1029/2020GC009495},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020GC009495},
	author = {Saikia, Utpal and Rychert, Catherine and Harmon, Nicholas and Kendall, J. M.}
}
@article {zhu_upper_2021,
	title = {Upper Mantle Hydration Indicated by Decreased Shear Velocity Near the Southern Mariana Trench From Rayleigh Wave Tomography},
	journal = {Geophysical Research Letters},
	volume = {48},
	number = {15},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2021GL093309},
	month = {07/2021},
	pages = {e2021GL093309},
	abstract = {Reduction of seismic velocities has been employed to study the hydration of incoming plates and forearc mantle in recent years. However, few constraints have been obtained in the Southern Mariana Trench. We use an ocean bottom seismograph (OBS) deployment to conduct Rayleigh wave tomographic studies to derive the SV-wave velocity structure near the Southern Mariana Trench. Measured group and phase velocities as a function of period are inverted to determine the SV-wave velocity using a Bayesian Monte Carlo algorithm. The incoming Pacific Plate is characterized by low velocities (3.6{\textendash}4.1 km/s) within the upper \~{}25 km of the mantle near the trench, indicating extensive mantle hydration of the incoming plate in southern Mariana. The velocity reduction in the forearc mantle is not as large as in central Mariana, most likely indicating a lower forearc serpentinization in this region, which is consistent with the absence of serpentinite mud volcanoes.},
	issn = {1944-8007},
	doi = {10.1029/2021GL093309},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021GL093309},
	author = {Zhu, Gaohua and Wiens, Douglas A. and Yang, Hongfeng and Lin, Jian and Xu, Min and You, Qingyu}
}
@article {barcheck_alaska_2020,
	title = {The Alaska Amphibious Community Seismic Experiment},
	journal = {Seismological Research Letters},
	volume = {91},
	number = {6},
	year = {2020},
	month = {08/2020},
	pages = {3054{\textendash}3063},
	abstract = {The Alaska Amphibious Community Seismic Experiment (AACSE) is a shoreline-crossing passive- and active-source seismic experiment that took place from May 2018 through August 2019 along an \~{}700  km long section of the Aleutian subduction zone spanning Kodiak Island and the Alaska Peninsula. The experiment featured 105 broadband seismometers; 30 were deployed onshore, and 75 were deployed offshore in Ocean Bottom Seismometer (OBS) packages. Additional strong-motion instruments were also deployed at six onshore seismic sites. Offshore OBS stretched from the outer rise across the trench to the shelf. OBSs in shallow water (\&lt;262  m depth) were deployed with a trawl-resistant shield, and deeper OBSs were unshielded. Additionally, a number of OBS-mounted strong-motion instruments, differential and absolute pressure gauges, hydrophones, and temperature and salinity sensors were deployed. OBSs were deployed on two cruises of the R/V Sikuliaq in May and July 2018 and retrieved on two cruises aboard the R/V Sikuliaq and R/V Langseth in August{\textendash}September 2019. A complementary 398-instrument nodal seismometer array was deployed on Kodiak Island for four weeks in May{\textendash}June 2019, and an active-source seismic survey on the R/V Langseth was arranged in June 2019 to shoot into the AACSE broadband network and the nodes. Additional underway data from cruises include seafloor bathymetry and sub-bottom profiles, with extra data collected near the rupture zone of the 2018 Mw~7.9 offshore-Kodiak earthquake. The AACSE network was deployed simultaneously with the EarthScope Transportable Array (TA) in Alaska, effectively densifying and extending the TA offshore in the region of the Alaska Peninsula. AACSE is a community experiment, and all data were made available publicly as soon as feasible in appropriate repositories.},
	issn = {0895-0695},
	doi = {10.1785/0220200189},
	url = {https://doi.org/10.1785/0220200189},
	author = {Barcheck, Grace and Abers, Geoffrey A. and Adams, Aubreya N. and B{\'e}cel, Anne and Collins, John and Gaherty, James B. and Haeussler, Peter J. and Li, Zongshan and Moore, Ginevra and Onyango, Evans and Roland, Emily and Sampson, Daniel E. and Schwartz, Susan Y. and Sheehan, Anne F. and Shillington, Donna J. and Shore, Patrick J. and Webb, Spahr and Wiens, Douglas A. and Worthington, Lindsay L.}
}
@article {113,
	title = {Body Wave Tomography of the Cascadia Subduction Zone and Juan de Fuca Plate System: Identifying Challenges and Solutions for Shore-Crossing Data},
	journal = {Geochemistry Geophysics Geosystems},
	volume = {21},
	year = {2020},
	type = {Journal Article},
	abstract = {Recent seismic results from the Cascadia Initiative indicate that heterogeneity in the oceanic asthenosphere affects subduction dynamics. Accurate characterization of the oceanic upper mantle is thus necessary to fully understand subduction processes, including the behavioral segmentation of the megathrust. A key challenge is integrating onshore and offshore datasets, which span large variations in near-surface features that teleseismic body wave tomography is ill-posed to resolve. Here, we perform a series of P and S forward modeling predictions to better understand the relative contribution of elevation, crustal thickness, offshore sedimentation, and near-surface velocity structure to teleseismic delay times. Crustal thickness and elevation variations dominate the signal, contributing \~{}1 s of delay time difference for P-waves (roughly double for S). We test several inversion strategies to account for near-surface features, identifying potential artifacts and causes of imaging errors. Undamped station statics are found to absorb mantle structures and introduce low-velocity artifacts beneath the forearc. Our preferred inversion strategy utilizes a three-dimensional starting model (including elevation) of the upper 50 km and heavily damped station statics, which we find leads to better resolution of mantle structure, particularly at asthenospheric depths. These insights guide inversions of observed delay times from the Cascadia subduction zone and Juan de Fuca plate system. We present a new onshore-offshore S model and an updated P model. Major features are common to both models, including localized subslab low-velocity anomalies, along-strike variations in slab structure, and offshore heterogeneity, while regional differences may reflect changes in Vp/Vs.},
	doi = {10.1029/2020gc009316},
	url = {https://app.dimensions.ai/details/publication/pub.1132665170},
	author = {Bodmer, M. and Toomey, D. R. and VanderBeek, B. and Hooft, E. E. and Byrnes, J. S.}
}
@article {eilon_depth-dependent_2020,
	title = {Depth-Dependent Azimuthal Anisotropy Beneath the Juan de Fuca Plate System},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {125},
	number = {8},
	year = {2020},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2020JB019477},
	pages = {e2020JB019477},
	abstract = {We use surface wave measurements to reveal anisotropy as a function of depth within the Juan de Fuca and Gorda plate system. Using a two-plane wave method, we measure phase velocity and azimuthal anisotropy of fundamental mode Rayleigh waves, solving for anisotropic shear velocity. These surface wave measurements are jointly inverted with constraints from SKS splitting studies using a Markov chain approach. We show that the two data sets are consistent and present inversions that offer new constraints on the vertical distribution of strain beneath the plates and the processes at spreading centers. Anisotropy of the Juan de Fuca plate interior is strongest ( 2.4\%) in the low-velocity zone between 40- to 90-km depth, with ENE direction driven by relative shear between plate motion and mantle return flow from the Cascadia subduction zone. In disagreement with Pn measurements, weak ( 1.1\%) lithospheric anisotropy in Juan de Fuca is highly oblique to the expected ridge-perpendicular direction, perhaps connoting complex intralithospheric fabrics associated with melt or off-axis downwelling. In the Gorda microplate, strong shallow anisotropy ( 1.9\%) is consistent with Pn inversions and aligned with spreading and may be enhanced by edge-driven internal strain. Weak anisotropy with ambiguous orientation in the low-velocity zone can be explained by Gorda{\textquoteright}s youth and modest motion relative to the Pacific. Deeper (>=90 km) fabric appears controlled by regional flow fields modulated by the Farallon slab edge: anisotropy is strong ( 1.8\%) beneath Gorda, but absent beneath the Juan de Fuca, which is in the strain shadow of the slab.},
	keywords = {mantle fabric, oceanic asthenosphere, oceanic lithosphere, surface wave anisotropy},
	issn = {2169-9356},
	doi = {10.1029/2020JB019477},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020JB019477},
	author = {Eilon, Zachary C. and Forsyth, Donald W.}
}
@article {becel_evidence_2020,
	title = {Evidence for a Prolonged Continental Breakup Resulting From Slow Extension Rates at the Eastern North American Volcanic Rifted Margin},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {125},
	number = {9},
	year = {2020},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2020JB020093},
	pages = {e2020JB020093},
	abstract = {When continental rifting is accompanied by localized magmatism under extensional stress, the breakup duration can be short and the continent/ocean transition sharp, as mantle melts are thought to be efficient at heating and weakening the lithosphere. This mode of rifting has been invoked for the Eastern North American Margin (ENAM) based on the existing geophysical data. Here, we present results from multichannel seismic profiles from the ENAM Community Seismic Experiment offshore North Carolina, U.S. Our survey area encompasses both the East Coast Magnetic Anomaly (ECMA) and the Blake Spur Magnetic Anomaly (BSMA), which lies 200-km farther seaward. Our prestack depth-migrated seismic images reveal major changes in the structure of the igneous crust across the BSMA. Between the ECMA and BSMA, we image a proto-oceanic domain of rough, faulted, and thin igneous crust. The roughness of this oceanic crust is similar to modern ultraslow spreading environments which involve the continued presence of a pre-existing lithospheric lid. Seaward of the BSMA the basement is smooth, and the crust is relatively thick, which is typical for Jurassic oceanic crust. Across the BSMA, we image a step up in basement and crustal root, which we interpret to represent complete lithospheric breakup and a transition to steady-state seafloor spreading in agreement with coincident refraction results. Our results would also indicate low extension rates in the final stages of rifting that may have influenced the thermal structure of the lithosphere and could explain the delay for continental breakup. All of these observations show that although continental rifting between eastern North America and northwest Africa was assisted by magmatic activity, it did not lead to rapid localization of extensional strain as previously thought.},
	keywords = {Central Atlantic opening, continental breakup, continental margin, proto-oceanic crust, steady-state seafloor spreading, volcanic rifted margin},
	issn = {2169-9356},
	doi = {10.1029/2020JB020093},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020JB020093},
	author = {B{\'e}cel, Anne and Davis, Joshua K. and Shuck, Brandon D. and Van Avendonk, Harm J. A. and Gibson, James C.}
}
@article {harmon_evolution_2020,
	title = {Evolution of the Oceanic Lithosphere in the Equatorial Atlantic From Rayleigh Wave Tomography, Evidence for Small-Scale Convection From the PI-LAB Experiment},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {21},
	number = {9},
	year = {2020},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020GC009174},
	month = {08/2020},
	pages = {e2020GC009174},
	abstract = {The oceanic lithosphere is a primary component of the plate tectonic system, yet its evolution and its asthenospheric interaction have rarely been quantified by in situ imaging at slow spreading systems. We use Rayleigh wave tomography from noise and teleseismic surface waves to image the shear wave velocity structure of the oceanic lithosphere-asthenosphere system from 0 to 80 My at the equatorial Mid-Atlantic Ridge using data from the Passive Imaging of the Lithosphere-Asthenosphere Boundary (PI-LAB) experiment. We observe fast lithosphere (VSV > 4.4 km/s) that thickens from 20{\textendash}30 km near the ridge axis to 70 km at seafloor >60 My. We observe several punctuated slow velocity anomalies (VSV < 4.1 km/s) in the asthenosphere between 50 and 150 km depth, not necessarily focused beneath the ridge axis. Some of the slow velocity regions are located within 100 km of the ridge axis, but other slow velocity regions are observed at distances > 400 km from the ridge. We observe a high velocity lithospheric downwelling drip beneath 30 My seafloor that extends to 80{\textendash}130 km depth. The asthenospheric slow velocities likely require partial melt. Although melt is present off axis, the lack of off-axis volcanism suggests the lithosphere acts as a permeability boundary for deeper melts. The punctuated and off-axis character of the asthenospheric anomalies and lithospheric drip suggests small-scale convection is active at a range of seafloor ages. Small-scale convection and/or more complex mantle flow may be aided by the presence of large offset fracture zones and/or the presence of melt and its associated low-viscosities and enhanced buoyancies.},
	keywords = {asthenosphere, Atlantic Ocean, oceanic lithosphere, PI-LAB, shear velocity, surface wave tomography},
	issn = {1525-2027},
	doi = {10.1029/2020GC009174},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020GC009174},
	author = {Harmon, Nicholas and Rychert, Catherine A. and Kendall, J. Michael and Agius, Matthew and Bogiatzis, Petros and Tharimena, Saikiran}
}
@article {wei_high_2020,
	title = {High Bulk and Shear Attenuation Due to Partial Melt in the Tonga-Lau Back-arc Mantle},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {125},
	number = {1},
	year = {2020},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2019JB017527},
	pages = {e2019JB017527},
	abstract = {Seismic attenuation measures energy loss during seismic wave propagation and quantifies the relaxation of rocks{\textquoteright} elastic moduli. Abundant seismic studies have observed shear attenuation, but few have quantified bulk attenuation (bulk modulus relaxation), and these studies controversially locate finite bulk attenuation in different parts of the Earth, from the asthenosphere to the inner core. Here we present conclusive evidence localizing bulk attenuation to a specific region of the uppermost mantle. By analyzing amplitude spectral decay of P and S waves from Tonga earthquakes recorded at local seismic stations, we observe unusually low QP/QS ratios (<1.5) in the Tonga-Lau mantle wedge. All seismic raypaths with significant path-average bulk attenuation (Qκ-1 > 0.01 or Qκ < 100) are confined to the region immediately beneath the Lau back-arc spreading centers west of the Tonga Arc. Tomography results show that the highest bulk attenuation (Qκ-1 = 0.037 {\textpm} 0.008 or Qκ = 27.0 {\textpm} 0.2) is about 75\% of the in situ shear attenuation. The observed high bulk attenuation anomalies coincide with an inferred zone of partial melting, suggesting that the causative mechanism involves either infinitesimal movement of melt through pores or changes in melt fraction in response to seismic waves.},
	keywords = {bulk attenuation, Lau back-arc basin, mantle partial melting, QP/QS ratio, Tonga subduction zone},
	issn = {2169-9356},
	doi = {10.1029/2019JB017527},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JB017527},
	author = {Wei, S. Shawn and Wiens, Douglas A.}
}
@article {miller_limited_2020,
	title = {Limited mantle hydration by bending faults at the Middle America Trench},
	journal = {Journal of Geophysical Research: Solid Earth},
	year = {2020},
	note = {Type: Journal Article},
	month = {12/2020},
	abstract = {Seismic anisotropy measurements show that upper mantle hydration at the Middle America Trench (MAT) is limited to serpentinization and/or water in fault zones, rather than distributed uniformly. Subduction of hydrated oceanic lithosphere recycles water back into the deep mantle, drives arc volcanism, and affects seismicity at subduction zones. Constraining the extent of upper mantle hydration is an important part of understanding many fundamental processes on Earth. Substantially reduced seismic velocities in tomography suggest that outer rise plate-bending faults provide a pathway for seawater to rehydrate the slab mantle just prior to subduction. Estimates of outer-rise hydration based on tomograms vary significantly, with some large enough to imply that, globally, subduction has consumed more than two oceans worth of water during the Phanerozoic. We found that, while the mean upper mantle wavespeed is reduced at the MAT outer rise, the amplitude and orientation of inherited anisotropy are preserved at depths >1 km below the Moho. At shallower depths, relict anisotropy is replaced by slowing in the fault-normal direction. These observations are incompatible with pervasive hydration but consistent with models of wave propagation through serpentinized fault zones that thin to <100-m in width at depths >1 km below Moho. Confining hydration to fault zones reduces water storage estimates for the MAT upper mantle from \~{}3.5 wt\% to <0.9 wt\% H20. Since the intermediate thermal structure in the \~{}24 Myr-old MAT slab favors serpentinization, limited hydration suggests that fault mechanics are the limiting factor, not temperatures. Subducting mantle may be similarly dry globally. This article is protected by copyright. All rights reserved. Upper mantle anisotropy indicates that hydration by fluid flow along bending faults is limited to fault zones that thin with depthConfining hydration to fault zones reduces estimates of water storage by an order of magnitudeA dry, intermediate-age slab mantle suggests that hydration may be globally limited by fault dynamics, rather than temperature Upper mantle anisotropy indicates that hydration by fluid flow along bending faults is limited to fault zones that thin with depth Confining hydration to fault zones reduces estimates of water storage by an order of magnitude A dry, intermediate-age slab mantle suggests that hydration may be globally limited by fault dynamics, rather than temperature.},
	keywords = {outer-rise hydration, upper mantle anisotropy, upper mantle hydration},
	doi = {10.1029/2020jb020982},
	url = {https://app.dimensions.ai/details/publication/pub.1133689698},
	author = {Miller, Nathaniel C. and Lizarralde, Daniel and Collins, John A. and Holbrook, W. Steven and Van Avendonk, H.}
}
@article {116,
	title = {Limited mantle hydration by bending faults at the Middle America Trench},
	journal = {Journal of Geophysical Research: Solid Earth},
	year = {2020},
	type = {Journal Article},
	abstract = {Seismic anisotropy measurements show that upper mantle hydration at the Middle America Trench (MAT) is limited to serpentinization and/or water in fault zones, rather than distributed uniformly. Subduction of hydrated oceanic lithosphere recycles water back into the deep mantle, drives arc volcanism, and affects seismicity at subduction zones. Constraining the extent of upper mantle hydration is an important part of understanding many fundamental processes on Earth. Substantially reduced seismic velocities in tomography suggest that outer rise plate-bending faults provide a pathway for seawater to rehydrate the slab mantle just prior to subduction. Estimates of outer-rise hydration based on tomograms vary significantly, with some large enough to imply that, globally, subduction has consumed more than two oceans worth of water during the Phanerozoic. We found that, while the mean upper mantle wavespeed is reduced at the MAT outer rise, the amplitude and orientation of inherited anisotropy are preserved at depths >1 km below the Moho. At shallower depths, relict anisotropy is replaced by slowing in the fault-normal direction. These observations are incompatible with pervasive hydration but consistent with models of wave propagation through serpentinized fault zones that thin to <100-m in width at depths >1 km below Moho. Confining hydration to fault zones reduces water storage estimates for the MAT upper mantle from \~{}3.5 wt\% to <0.9 wt\% H20. Since the intermediate thermal structure in the \~{}24 Myr-old MAT slab favors serpentinization, limited hydration suggests that fault mechanics are the limiting factor, not temperatures. Subducting mantle may be similarly dry globally. This article is protected by copyright. All rights reserved. Upper mantle anisotropy indicates that hydration by fluid flow along bending faults is limited to fault zones that thin with depthConfining hydration to fault zones reduces estimates of water storage by an order of magnitudeA dry, intermediate-age slab mantle suggests that hydration may be globally limited by fault dynamics, rather than temperature Upper mantle anisotropy indicates that hydration by fluid flow along bending faults is limited to fault zones that thin with depth Confining hydration to fault zones reduces estimates of water storage by an order of magnitude A dry, intermediate-age slab mantle suggests that hydration may be globally limited by fault dynamics, rather than temperature.},
	doi = {10.1029/2020jb020982},
	url = {https://app.dimensions.ai/details/publication/pub.1133689698},
	author = {Miller, Nathaniel C. and Lizarralde, Daniel and Collins, John A. and Holbrook, W. Steven and Van Avendonk, H.}
}
@article {McVey2020,
	title = {Magma accumulation beneath Santorini volcano, Greece, from P-wave tomography},
	journal = {Geology},
	volume = {48},
	number = {3},
	year = {2020},
	month = {mar},
	pages = {231{\textendash}235},
	abstract = {Despite multidisciplinary evidence for crustal magma accumulation below Santorini volcano, Greece, the structure and melt content of the shallow magmatic system remain poorly constrained. We use three-dimensional (3-D) velocity models from tomographic inversions of active-source seismic P-wave travel times to identify a pronounced low-velocity anomaly ({\textendash}21\%) from 2.8 km to 5 km depth localized below the northern caldera basin. This anomaly is consistent with depth estimates of pre-eruptive storage and a recent inflation episode, supporting the interpretation of a shallow magma body that causes seismic attenuation and ray bending. A suite of synthetic tests shows that the geometry is well recovered while a range of melt contents (4\%{\textendash}13\% to fully molten) are allowable. A thin mush region (2\%{\textendash}7\% to 3\%{\textendash}10\% melt) extends from the main magma body toward the northeast, observed as low velocities confined by tectono-magmatic lineaments. This anomaly terminates northwest of Kolumbo; little to no melt underlies the seamount from 3 to 5 km depth. These structural constraints suggest that crustal extension and edifice loads control the geometry of magma accumulation and emphasize that the shallow crust remains conducive to melt storage shortly after a caldera-forming eruption.},
	issn = {0091-7613},
	doi = {10.1130/G47127.1},
	url = {https://pubs.geoscienceworld.org/gsa/geology/article/48/3/231/579527/Magma-accumulation-beneath-Santorini-volcano},
	author = {McVey, B.G. and Hooft, E.E.E. and Heath, B.A. and Toomey, D.R. and Paulatto, M. and Morgan, J.V. and Nomikou, P. and Papazachos, C.B.}
}
@article {wei_obs_2020,
	title = {An OBS Array to Investigate Offshore Seismicity during the 2018~Kilauea Eruption},
	journal = {Seismological Research Letters},
	volume = {92},
	number = {1},
	year = {2020},
	month = {01/2021},
	pages = {603{\textendash}612},
	abstract = {On 3 May 2018, Kilauea Volcano, one of the most active volcanoes in the world, entered a new eruptive phase because of a dike intrusion in the East Rift zone. One day later, an Mw~6.9 earthquake, which was likely trigged by the dike intrusion, occurred in the submarine south flank of Kilauea Volcano. In mid-July, an ocean-bottom seismometer (OBS) array consisting of 12 stations was deployed on the submarine south flank of Kilauea Volcano to monitor the aftershocks and lava{\textendash}water interaction near the ocean entry. Eleven OBSs were recovered in mid-September. Preliminary evaluation of the data reveals a large number of seismic and acoustic events, which provide a valuable dataset for understanding flank deformation and stability as well as lava{\textendash}water interaction. Here, we introduce this dataset and document notable instrument malfunctions along with some initial seismic and acoustic observations.},
	issn = {0895-0695},
	doi = {10.1785/0220200206},
	url = {https://doi.org/10.1785/0220200206},
	author = {Wei, XiaoZhuo and Shen, Yang and Caplan-Auerbach, Jacqueline and Morgan, Julia K.}
}
@article {115,
	title = {Physical Sources of High-Frequency Seismic Noise on Cascadia Initiative Ocean Bottom Seismometers},
	journal = {Geochemistry Geophysics Geosystems},
	volume = {21},
	year = {2020},
	type = {Journal Article},
	abstract = {Physical sources of high-frequency seismic noise in the ocean are investigated using data from the Cascadia Initiative (CI) ocean bottom seismometer (OBS) network, hindcasts of wind speed, waves, and the bottom currents predicted by a regional ocean circulation model and observed at sites on cabled observatories. Seismic data in the 5{\textendash}12 Hz band are considered because it is best for detecting regional earthquakes and lies between the frequencies of local microseisms and the seasonal whale calls. Median noise levels in this range vary by ~20 dB between sites at a given depth but on average decrease with increasing depth. On the continental shelf, the orbital motions of ocean waves are a major source of noise while at the quietest sites in the deep ocean, noise increases when wind speeds exceed ~10 m/s. On the continental slope and abyssal plain within about 100 km of the slope, seismic noise is not predicted at specific sites by the bottom currents in the ocean circulation model. In these regions, ocean currents are inferred to be the primary source of noise, because noise varies on tidal periods, is low on buried seismometers, and has spatial variations broadly consistent with those of median absolute currents. Comparisons between OBSs suggest that high-frequency noise is reduced by low-profile hydrodynamic designs but not by shielding. Many OBSs also record numerous short duration events on and near the continental shelf that have been attributed elsewhere to animals bumping into the sensor or gas bubbles moving through sediments. Environmental noise generated by waves, wind, and ocean currents limits the ability of seafloor seismometers to detect the ground motions from earthquakes. This research uses data from a large deployment of seafloor seismometers off the coast of the Pacific Northwest of America to understand the seismic noise at frequencies of 5{\textendash}12 Hz which coincides with the frequency band used to detect regional earthquakes. Instruments deployed in shallow water on the continental shelf record high noise levels caused by motions from ocean waves that reach the seafloor. The quietest sites are found in the deep ocean far from the coast, and here the noise is created by wind blowing spray from whitecaps. At intermediate sites on the continental slope and deep ocean just seaward of the continental slope, the noise results from ocean currents that are related to ocean circulation and tides. Some shallow instruments also record large numbers of short signals that are not earthquakes and may be either a result of animals bumping into the seismic sensor or gas bubbles moving through sediments. The best way to reduce seismic noise is to bury the seismic sensors, but when this is infeasible, the instruments should have a short hydrodynamic design. Seismic noise is high on the shelf due to wave orbital currents, and noise at the quietest abyssal plain sites is correlated with wind speed Ocean currents are the primary source of high-frequency noise on the continental slope and abyssal plain within ~100 km of the slope High-frequency current-generated seismic noise is reduced on OBSs with squat hydrodynamic designs and is not clearly reduced by shielding.},
	doi = {10.1029/2020gc009085},
	url = {https://app.dimensions.ai/details/publication/pub.1131195022},
	author = {Hilmo, Rose and Wilcock, William S. D.}
}
@article {eimer_seismicity_2020,
	title = {Seismicity of the Incoming Plate and Forearc Near the Mariana Trench Recorded by Ocean Bottom Seismographs},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {21},
	number = {4},
	year = {2020},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020GC008953},
	month = {04/2020},
	pages = {e2020GC008953},
	abstract = {Earthquakes near oceanic trenches are important for studying incoming plate bending and updip thrust zone seismogenesis, yet are poorly constrained using seismographs on land. We use an ocean bottom seismograph (OBS) deployment spanning both the incoming Pacific Plate and the forearc to study seismicity near the Mariana Trench. The yearlong deployment in 2012{\textendash}2013 consisted of 20 broadband OBSs and 5 suspended hydrophones, with an additional 59 short period OBSs and hydrophones recording for 1 month. We locate 1,692 earthquakes using a nonlinear method with a 3D velocity model constructed from active source profiles and surface wave tomography results. Events occurring seaward of the trench occur to depths of 35 km below the seafloor, and focal mechanisms of the larger events indicate normal faulting corresponding to plate bending. Significant seismicity emerges about 70 km seaward from the trench, and the seismicity rate increases continuously towards the trench, indicating that the largest bending deformation occurs near the trench axis. These plate-bending earthquakes occur along faults that facilitate the hydration of the subducting plate, and the lateral and depth distribution of earthquakes is consistent with low-velocity regions imaged in previous studies. The forearc is marked by a heterogeneous distribution of low magnitude (<5 Mw) thrust zone seismicity, possibly due to the rough incoming plate topography and/or serpentinization of the forearc. A sequence of thrust earthquakes occurs at depths 10 km below seafloor and within 20 km of the trench axis, demonstrating that the megathrust is seismically active nearly to the trench.},
	issn = {1525-2027},
	doi = {10.1029/2020GC008953},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020GC008953},
	author = {Eimer, Melody and Wiens, Douglas A. and Cai, Chen and Lizarralde, Daniel and Jasperson, Hope}
}
@article {parnell-turner_seismicity_2020,
	title = {Seismicity trends and detachment fault structure at 13{\textdegree}N, Mid-Atlantic Ridge},
	journal = {Geology},
	volume = {49},
	number = {3},
	year = {2020},
	month = {11/2020},
	pages = {320{\textendash}324},
	abstract = {At slow-spreading ridges, plate separation is commonly partly accommodated by slip on long-lived detachment faults, exposing upper mantle and lower crustal rocks on the seafloor. However, the mechanics of this process, the subsurface structure, and the interaction of these faults remain largely unknown. We report the results of a network of 56 ocean-bottom seismographs (OBSs), deployed in 2016 at the Mid-Atlantic Ridge near 13{\textdegree}N, that provided dense spatial coverage of two adjacent detachment faults and the intervening ridge axis. Although both detachments exhibited high levels of seismicity, they are separated by an \~{}8-km-wide aseismic zone, indicating that they are mechanically decoupled. A linear band of seismic activity, possibly indicating magmatism, crosscuts the 13{\textdegree}30'N domed detachment surface, confirming previous evidence for fault abandonment. Farther south, where the 2016 OBS network spatially overlapped with a similar survey done in 2014, significant changes in the patterns of seismicity between these surveys are observed. These changes suggest that oceanic detachments undergo previously unobserved cycles of stress accumulation and release as plate spreading is accommodated.},
	issn = {0091-7613},
	doi = {10.1130/G48420.1},
	url = {https://doi.org/10.1130/G48420.1},
	author = {Parnell-Turner, R. and Sohn, R.A. and Peirce, C. and Reston, T.J. and MacLeod, C.J. and Searle, R.C. and Sim{\~a}o, N.M.}
}
@article {ma_shear_2020,
	title = {Shear attenuation and anelastic mechanisms in the central Pacific upper mantle},
	journal = {Earth and Planetary Science Letters},
	volume = {536},
	year = {2020},
	month = {04/2020},
	pages = {116148},
	abstract = {We determine the mantle attenuation (1/Qμ) structure beneath 70 Myr seafloors in the central Pacific. We use long-period (33-100 sec) Rayleigh waves recorded by the NoMelt array of broadband ocean-bottom seismometers. After the removal of tilt and compliance noise, we are able to measure Rayleigh wave phase and amplitude for 125 earthquakes. The compliance correction for ocean wave pressure on the seafloor is particularly important for improving signal-to-noise at periods longer than 55 sec. Attenuation and azimuthally anisotropic phase velocity in the study area are determined by approximating the wavefield as the interference of two plane waves. We find that the amplitude decay of Rayleigh waves across the NoMelt array can be adequately explained using a two-layer model: Qμ=1400 in the shallow layer, Qμ=110 in the deeper layer, and a transition depth at 70 km, although the sharpness of the transition is not well resolved by the Rayleigh wave data. Notably, Qμ observed in the NoMelt lithosphere is significantly higher than values in this area from global attenuation models. When compared with lithospheric Qμ measured at higher frequency (\~{}3 Hz), the frequency dependence of attenuation is very slight, revising previous interpretations. The effect of anelasticity on shear velocity (VS) is estimated from the ratio of observed velocity to the predicted anharmonic value. We use laboratory-based parameters to predict attenuation and velocity-dispersion spectra that result from the superposition of a weakly frequency dependent high-temperature background and an absorption peak. We test a large range of frequencies for the position of the absorption peak (fe) and determine, at each depth, which values of fe predict Qμ and VS that can fit the NoMelt Qμ and VS values simultaneously. We show that between depths of 60 and 80 km the seismic models require an increase in fe by at least 3-4 orders of magnitude. Under the assumption that the absorption peak is caused by elastically accommodated grain-boundary sliding, this increase in fe reflects a decrease in grain-boundary viscosity of 3-4 orders of magnitude. A likely explanation is an increase in the water content of the mantle, with the base of the dehydrated lid located at \~{}70-km depth.},
	keywords = {anelastic mechanism, oceanic lithosphere, Pacific Ocean, shear attenuation},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2020.116148},
	url = {https://www.sciencedirect.com/science/article/pii/S0012821X20300911},
	author = {Ma, Zhitu and Dalton, Colleen A. and Russell, Joshua B. and Gaherty, James B. and Hirth, Greg and Forsyth, Donald W.}
}
@article {bogiatzis_source_2020,
	title = {Source Regions of Infragravity Waves Recorded at the Bottom of the Equatorial Atlantic Ocean, Using OBS of the PI-LAB Experiment},
	journal = {Journal of Geophysical Research: Oceans},
	volume = {125},
	number = {6},
	year = {2020},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2019JC015430},
	month = {05/2020},
	pages = {e2019JC015430},
	abstract = {Infragravity waves are generated along coasts, and some small fraction of their energy escapes to the open oceans and propagates with little attenuation. Due to the scarcity of deep-ocean observations of these waves, the mechanism and the extent of the infragravity waves energy leakage from the coasts remains poorly understood. Understanding the generation and pathways of infragravity wave energy is important among others for understanding the breakup of ice-shelves and the contamination of high-resolution satellite radar altimetry measurements of sea level. We examine data from 37 differential pressure gauges of Ocean Bottom Seismometers (OBS) near the equatorial mid-Atlantic ridge, deployed during the Passive Imaging of the Lithosphere-Asthenosphere Boundary (PI-LAB) experiment. We use the beamforming technique to investigate the incoming directions of infragravity waves. Next, we develop a graph-theory-based global back-projection method of noise cross-correlation function envelopes, which minimizes the effects of array geometry using an adaptive weighting scheme. This approach allows us to locate the sources of the infragravity energy. We assess our observations by comparing to a global model of infragravity wave heights. Our results reveal strong coherent energy from sources and/or reflected phases at the west coast of Africa and some sources from South America. These energy sources are in good agreement with the global infragravity wave model. In addition, we also observe infragravity waves arriving from North America during specific events that mostly occur during October{\textendash}February 2016. Finally, we find indications of waves that propagate with little attenuation, long distances through sea ice, reflecting off Antarctica.},
	keywords = {Africa, Antarctica, Atlantic Ocean, back-projection, beamforming, infragravity waves},
	issn = {2169-9291},
	doi = {10.1029/2019JC015430},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JC015430},
	author = {Bogiatzis, P. and Karamitrou, A. and Ward Neale, J. and Harmon, N. and Rychert, C. A. and Srokosz, M.}
}
@article {114,
	title = {South Atlantic Transect: Variations in Oceanic Crustal Structure at 31{\textdegree}S},
	journal = {Geochemistry Geophysics Geosystems},
	volume = {21},
	year = {2020},
	type = {Journal Article},
	abstract = {We present an analysis of geophysical data acquired along a transect of 0{\textendash}62 Ma crust located on the western flank of the Mid-Atlantic Ridge at 31{\textdegree}S; all crust was formed at the same ridge segment. Crustal thickness, constrained by five wide-angle profiles, has mean values of 5.6 km at 6.6 and 15.2 Ma, 7.0 km at 30.6 Ma, 5.5 km at 49.2 Ma, and 3.6 km at 61.2 Ma. Crustal thickness is uniform along each ridge-parallel profile (standard deviations 0.1{\textendash}0.3 km), indicating uniform along-axis magmatic accretion over lateral distances of 40{\textendash}60 km. The crustal structure of 61.2 Ma crust is not only anomalously thin compared to the other profiles but also contains regions with a linear velocity gradient from seafloor to Moho, which suggests that intense fracturing may extend to the base of the thin crust. Abyssal hill root-mean-square heights in the study region are 57{\textendash}142 m and have an inverse correlation with spreading rate. These values are lower than the average root-mean-square height of 196 m elsewhere on the southern Mid-Atlantic Ridge and indicate relatively high mantle temperatures in our study area. Unsedimented or lightly sedimented basement highs are prevalent at all ages; we argue that bottom currents scour the high topography, transporting sediment into adjacent basement lows. All drillsites planned for International Ocean Discovery Program Expeditions 390 and 393 are within 1{\textendash}10 km of unsedimented or lightly sedimented basement highs, which should facilitate fluid flow and continued geochemical exchange between crust and seafloor.},
	doi = {10.1029/2020gc009017},
	url = {https://app.dimensions.ai/details/publication/pub.1128393051},
	author = {Christeson, G. L. and Reece, R. S. and Kardell, D. A. and Estep, J. D. and Fedotova, A. and Goff, J. A.}
}
@article {117,
	title = {Temporal and spatial variations in seismic anisotropy and V P /V S ratios in a region of slow slip},
	journal = {Earth and Planetary Science Letters},
	volume = {532},
	year = {2020},
	pages = {115970},
	type = {Journal Article},
	abstract = {In September 2014, a five week long slow slip event (SSE) occurred near Gisborne at the northern Hikurangi subduction zone, New Zealand, and was recorded by offshore instruments deployed by the Hikurangi Ocean Bottom Investigation of Tremor and Slow Slip (HOBITSS) project. Up to 25 cm of slip occurred directly below the HOBITSS array. We calculate shear wave splitting (SWS) and V P / V S ratios for event-station pairs on HOBITSS ocean bottom seismometers and onshore GeoNet seismic stations to determine the relationship in time and space between slow slip and these seismic properties. Spatial averaging of SWS fast azimuths yields trench-perpendicular fast azimuths in some areas, suggesting that compressive stress from plate convergence closes microcracks and controls anisotropy in the upper-plate. Variations from the trench perpendicular directions are observed near a subducting seamount, with directions closely resembling fracture and fault patterns created by subducting seamounts previously observed in both laboratory and field experiments. Temporal variations in fast azimuths are observed at three stations, two of which are located above the seamount, suggesting measurable variations in stress orientations. During the SSE, median V P / V S measurements across all offshore stations increase from 1.817 to 1.894 and SWS delay times decrease from 0.178 s to 0.139 s (both changes are significant within 95\% confidence intervals). Temporal variations in V P / V S and delay time are consistent with fluid pressurization below a permeability barrier and movement of fluids during the rupture of a slow-slip patch.},
	doi = {10.1016/j.epsl.2019.115970},
	url = {https://app.dimensions.ai/details/publication/pub.1123727644},
	author = {Zal, Hubert Jerzy and Jacobs, Katrina and Savage, Martha Kane and Yarce, Jefferson and Mroczek, Stefan and Graham, Kenny and Todd, Erin K. and Nakai, Jenny and Iwasaki, Yuriko and Sheehan, Anne and Mochizuki, Kimihiro and Wallace, Laura and Schwartz, Susan and Webb, Spahr and Henrys, Stuart}
}
@article {lata_uppermost_2020,
	title = {Uppermost crustal structure across the eastern Lau spreading center from P-to-S converted waves},
	journal = {Marine Geophysical Research},
	volume = {41},
	number = {4},
	year = {2020},
	month = {11/2020},
	abstract = {P and S wave data from the L-SCAN active-source wide-angle reflection/refraction experiment are modelled to investigate upper crustal structure in the Lau backarc basin. A combination of ray tracing and finite difference numerical wavefield simulation is used to identify P and P-to-S converted seismic phases. The phases primarily arise from two shallow interfaces, one at \textasciitilde 80~m depth or less, and the other at 500{\textendash}650~m depth. The shallower interface is deeper than the sediment base, is observed across the study area, and is interpreted as a {\textquoteleft}layer 2Aa{\textquoteright} boundary, proposed to result from a rapid change in crack density. The deeper interface is interpreted as the layer 2A{\textendash}2B boundary, corresponding to a transition from lavas to sheeted dykes. Layer 2A, on average, is 150~m thicker in crust that formed at the spreading center when spreading was located near the arc (< 50~km away), as compared to when spreading was located farther away from the arc (> 70~km away). Layer 2A thickness and Vp/Vs values indicate that a thicker and more porous lava layer, dominated by basalts to basalt-andesites, cap near-arc crust, while a thinner and less-porous, mostly basaltic, volcanic layer caps the far-arc crust. These results are consistent with the waning influence of slab-derived volatiles on crustal formation as seafloor spreading moves away from the active arc.},
	keywords = {Backarc spreading center, oceanic crust, S-waves, subduction zone},
	issn = {1573-0581},
	doi = {10.1007/s11001-020-09419-5},
	url = {https://doi.org/10.1007/s11001-020-09419-5},
	author = {Lata, Charu and Dunn, Robert A.}
}
@article {cooper_variable_2020,
	title = {Variable water input controls evolution of the Lesser Antilles volcanic arc},
	journal = {Nature},
	volume = {582},
	number = {7813},
	year = {2020},
	note = {Number: 7813 Publisher: Nature Publishing Group},
	month = {jun},
	pages = {525{\textendash}529},
	abstract = {Oceanic lithosphere carries volatiles, notably water, into the mantle through subduction at convergent plate boundaries. This subducted water exercises control on the production of magma, earthquakes, formation of continental crust and mineral resources. Identifying different potential fluid sources (sediments, crust and mantle lithosphere) and tracing fluids from their release to the surface has proved challenging1. Atlantic subduction zones are a valuable endmember when studying this deep water cycle because hydration in Atlantic lithosphere, produced by slow spreading, is expected to be highly non-uniform2. Here, as part of a multi-disciplinary project in the Lesser Antilles volcanic arc3, we studied boron trace element and isotopic fingerprints of melt inclusions. These reveal that serpentine{\textemdash}that is, hydrated mantle rather than crust or sediments{\textemdash}is a dominant supplier of subducted water to the central arc. This serpentine is most likely to reside in a set of major fracture zones subducted beneath the central arc over approximately the past ten million years. The current dehydration of these fracture zones coincides with the~current locations of the highest rates of earthquakes and prominent low shear velocities, whereas the preceding history~of~dehydration is consistent with the locations of~higher volcanic productivity and thicker arc crust. These combined geochemical and geophysical data indicate that the structure and hydration of the subducted plate are directly connected to the evolution of the arc and its associated seismic and volcanic hazards.},
	keywords = {Geochemistry, Geodynamics, Geophysics, seismology, Volcanology},
	issn = {1476-4687},
	doi = {10.1038/s41586-020-2407-5},
	url = {https://www.nature.com/articles/s41586-020-2407-5},
	author = {Cooper, George F. and Macpherson, Colin G. and Blundy, Jon D. and Maunder, Benjamin and Allen, Robert W. and Goes, Saskia and Collier, Jenny S. and Bie, Lidong and Harmon, Nicholas and Hicks, Stephen P. and Iveson, Alexander A. and Prytulak, Julie and Rietbrock, Andreas and Rychert, Catherine A. and Davidson, Jon P.}
}
@article {118,
	title = {Vp/Vs Ratio of Incoming Sediments Off Cascadia Subduction Zone From Analysis of Controlled-Source Multicomponent OBS Records},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {125},
	year = {2020},
	type = {Journal Article},
	abstract = {P-to-S-converted waves observed in controlled-source multicomponent ocean bottom seismometer (OBS) records were used to derive the Vp/Vs structure of Cascadia Basin sediments. We used P-to-S waves converted at the basement to derive an empirical function describing the average Vp/Vs of Cascadia sediments as a function of sediment thickness. We derived one-dimensional interval Vp/Vs functions from semblance velocity analysis of S-converted intrasediment and basement reflections, which we used to define an empirical Vp/Vs versus burial depth compaction trend. We find that seaward from the Cascadia deformation front, Vp/Vs structure offshore northern Oregon and Washington shows little variability along strike, while the structure of incoming sediments offshore central Oregon is more heterogeneous and includes intermediate-to-deep sediment layers of anomalously elevated Vp/Vs. These zones with elevated Vp/Vs are likely due to elevated pore fluid pressures, although layers of high sand content intercalated within a more clayey sedimentary sequence, and/or a higher content of coarser-grained clay minerals relative to finer-grained smectite could be contributing factors. We find that the proto-d{\'e}collement offshore central Oregon develops within the incoming sediments at a low-permeability boundary that traps fluids in a stratigraphic level where fluid overpressure exceeds 50\% of the differential pressure between the hydrostatic pressure and the lithostatic pressure. Incoming sediments with the highest estimated fluid overpressures occur offshore central Oregon where deformation of the accretionary prism is seaward vergent. Conversely, landward vergence offshore northern Oregon and Washington correlates with more moderate pore pressures and laterally homogeneous Vp/Vs functions of Cascadia Basin sediments. Average and interval Vp/Vs versus depth functions derived from S-converted waves from the Ridge-to-Trench seismic experiment in Cascadia Basin Layers with high Vp/Vs indicate elevated pore fluid pressure in incoming sediments Variations in Vp/Vs structure correlate with underthrust sediment thickness and wedge deformation style.},
	doi = {10.1029/2019jb019239},
	url = {https://app.dimensions.ai/details/publication/pub.1127957341},
	author = {Zhu, Jian and Canales, J. Pablo and Han, Shuoshuo and Carbotte, Suzanne M. and Arnulf, Adrien and Nedimovi{\'c}, Mladen R.}
}
@article {eddy_age_2019,
	title = {Age dependence and anisotropy of surface-wave phase velocities in the Pacific},
	journal = {Geophysical Journal International},
	volume = {216},
	number = {1},
	year = {2019},
	month = {01/2019},
	pages = {640{\textendash}658},
	abstract = {We present new anisotropic phase-velocity maps of the Pacific basin for Rayleigh and Love waves between 25~and 250~s. The isotropic and anisotropic phase-velocity maps are obtained by inversion of a data set of single-station surface-wave phase-anomaly measurements recorded for paths crossing the Pacific basin. We develop an age-dependent gradient-damping scheme that allows us to reduce the amount of smoothness damping required in the inversion. The observed isotropic phase velocities have a strong age dependence, and our results are consistent with models of half-space cooling: simple phase-velocity models that depend only on seafloor age explain \$40\textbackslashtext{-}97\textbackslashhbox{ per cent}\$ of the data variance for Love waves and \$20\textbackslashtext{-}97\textbackslashhbox{ per cent}\$ for Rayleigh waves. These values represent a large fraction, ranging from 0.55 to 0.99, of the variance reduction of our best-fitting phase-velocity models. We find that 2ζ azimuthal anisotropy is required to fit our Rayleigh wave phase-anomaly data set but that our data do not require Love wave anisotropy. Rayleigh wave anisotropy also exhibits a clear age dependence, with a large decrease in the magnitude of 2ζ azimuthal anisotropy for seafloor older than 70~Ma that cannot be explained simply as a change in anisotropy direction between the lithosphere and asthenosphere. Long-period Rayleigh wave anisotropy directions align well overall with absolute-plate-motion directions, with a median angular misfit of 20{\textdegree} at 125~s. However, we observe large areas within the Pacific basin with a small but consistent offset of 10{\textdegree}{\textendash}20{\textdegree} between the two directions. The disagreement between absolute plate motion and anisotropy for long-period waves suggests the presence of mantle flow beneath the base of the plate in a direction other than absolute plate motion.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggy438},
	url = {https://doi.org/10.1093/gji/ggy438},
	author = {Eddy, Celia L and Ekstr{\"o}m, G{\"o}ran and Nettles, Meredith and Gaherty, James B}
}
@article {janiszewski_amphibious_2019,
	title = {Amphibious surface-wave phase-velocity measurements of the Cascadia subduction zone},
	journal = {Geophysical Journal International},
	volume = {217},
	number = {3},
	year = {2019},
	month = {jun},
	pages = {1929{\textendash}1948},
	abstract = {A new amphibious seismic data set from the Cascadia subduction zone is used to characterize the lithosphere structure from the Juan de Fuca ridge to the Cascades backarc. These seismic data are allowing the imaging of an entire tectonic plate from its creation at the ridge through the onset of the subduction to beyond the volcanic arc, along the entire strike of the Cascadia subduction zone. We develop a tilt and compliance correction procedure for ocean-bottom seismometers that employs automated quality control to calculate robust station noise properties. To elucidate crust and upper-mantle structure, we present shoreline-crossing Rayleigh-wave phase-velocity maps for the Cascadia subduction zone, calculated from earthquake data from 20 to 160 s period and from ambient-noise correlations from 9 to 20 s period. We interpret the phase-velocity maps in terms of the tectonics associated with the Juan de Fuca plate history and the Cascadia subduction system. We find that thermal oceanic plate cooling models cannot explain velocity anomalies observed beneath the Juan de Fuca plate. Instead, they may be explained by a <=1 per cent partial melt region beneath the ridge and are spatially collocated with patches of hydration and increased faulting in the crust and upper mantle near the deformation front. In the forearc, slow velocities appear to be more prevalent in areas that experienced high slip in past Cascadia megathrust earthquakes and generally occur updip of the highest-density tremor regions and locations of intraplate earthquakes. Beneath the volcanic arc, the slowest phase velocities correlate with regions of highest magma production volume.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggz051},
	url = {https://doi.org/10.1093/gji/ggz051},
	author = {Janiszewski, Helen A and Gaherty, James B and Abers, Geoffrey A and Gao, Haiying and Eilon, Zachary C}
}
@inbook {Heidarzadeh2019,
	title = {Application of Dense Offshore Tsunami Observations from Ocean Bottom Pressure Gauges (OBPGs) for Tsunami Research and Early Warnings},
	year = {2019},
	pages = {7{\textendash}22},
	doi = {10.1007/978-981-13-0992-2_2},
	url = {http://link.springer.com/10.1007/978-981-13-0992-2_2},
	author = {Heidarzadeh, Mohammad and Gusman, Aditya R.}
}
@article {mark_azimuthal_2019,
	title = {Azimuthal Seismic Anisotropy of 70-Ma Pacific-Plate Upper Mantle},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {124},
	number = {2},
	year = {2019},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2018JB016451},
	month = {02/2019},
	pages = {1889{\textendash}1909},
	abstract = {Plate formation and evolution processes are predicted to generate upper mantle seismic anisotropy and negative vertical velocity gradients in oceanic lithosphere. However, predictions for upper mantle seismic velocity structure do not fully agree with the results of seismic experiments. The strength of anisotropy observed in the upper mantle varies widely. Further, many refraction studies observe a fast direction of anisotropy rotated several degrees with respect to the paleospreading direction, suggesting that upper mantle anisotropy records processes other than 2-D corner flow and plate-driven shear near mid-ocean ridges. We measure 6.0 {\textpm} 0.3\% anisotropy at the Moho in 70-Ma lithosphere in the central Pacific with a fast direction parallel to paleospreading, consistent with mineral alignment by 2-D mantle flow near a mid-ocean ridge. We also find an increase in the strength of anisotropy with depth, with vertical velocity gradients estimated at 0.02 km/s/km in the fast direction and 0 km/s/km in the slow direction. The increase in anisotropy with depth can be explained by mechanisms for producing anisotropy other than intrinsic effects from mineral fabric, such as aligned cracks or other structures. This measurement of seismic anisotropy and gradients reflects the effects of both plate formation and evolution processes on seismic velocity structure in mature oceanic lithosphere, and can serve as a reference for future studies to investigate the processes involved in lithospheric formation and evolution.},
	issn = {2169-9356},
	doi = {10.1029/2018JB016451},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JB016451},
	author = {Mark, H. F. and Lizarralde, D. and Collins, J. A. and Miller, N. C. and Hirth, G. and Gaherty, J. B. and Evans, R. L.}
}
@article {doran_calibration_2019,
	title = {Calibration of Differential Pressure Gauges Through In Situ Testing},
	journal = {Earth and Space Science},
	volume = {6},
	number = {12},
	year = {2019},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2019EA000783},
	pages = {2663{\textendash}2670},
	abstract = {Differential pressure gauges (DPGs) are a standard component of modern broadband ocean-bottom seismometer instruments and have proven useful for observing a wide range of seismic and oceanographic phenomena. However, the response function of the DPG remains poorly known, limiting our ability to recover amplitude and phase information from seafloor pressure signals with high fidelity. The sensitivity and long-period response are difficult to calibrate in the lab, as they are known to vary with temperature and pressure and perhaps between sensors of the same design. We present the results of a field experiment designed to determine empirical response functions in situ by inducing a pre-defined pressure offset on a deployed instrument. The results compare favorably with calibrations estimated independently through post-deployment data analyses. Our study demonstrates that observed response functions can deviate from the nominal response by a factor of two or greater with regards to both the sensitivity and the time constant. Incorporating calibration devices such as those described here into future deployments may prove to be a cost-effective way to improve the accuracy and utility of differential pressure data.},
	issn = {2333-5084},
	doi = {10.1029/2019EA000783},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019EA000783},
	author = {Doran, A.k. and Rapa, M. and Laske, G. and Babcock, J. and McPeak, S.}
}
@article {Yang2019,
	title = {A Comprehensive Quality Analysis of Empirical Green{\textquoteright}s Functions at Ocean-Bottom Seismometers in Cascadia},
	journal = {Seismological Research Letters},
	volume = {90},
	number = {2A},
	year = {2019},
	month = {mar},
	pages = {744{\textendash}753},
	issn = {0895-0695},
	doi = {10.1785/0220180273},
	url = {https://pubs.geoscienceworld.org/ssa/srl/article/90/2A/744/567980/A-Comprehensive-Quality-Analysis-of-Empirical},
	author = {Yang, Xiaotao and Gao, Haiying and Rathnayaka, Sampath and Li, Cong}
}
@article {lynner_eastern_2019,
	title = {The Eastern North American Margin Community Seismic Experiment: An Amphibious Active- and Passive-Source Dataset},
	journal = {Seismological Research Letters},
	volume = {91},
	number = {1},
	year = {2019},
	month = {10/2019},
	pages = {533{\textendash}540},
	abstract = {The eastern North American margin community seismic experiment (ENAM-CSE) was conceived to target the ENAM Geodynamic Processes at Rifting and Subducting Margins (GeoPRISMS) primary site with a suite of both active- and passive-source seismic data that would shed light on the processes associated with rift initiation and evolution. To fully understand the ENAM, it was necessary to acquire a seismic dataset that was both amphibious, spanning the passive margin from the continental interior onto the oceanic portion of the North American plate, and multiresolution, enabling imaging of the sediments, crust, and mantle lithosphere. The ENAM-CSE datasets were collected on- and offshore of North Carolina and Virginia over a series of cruises and land-based deployments between April 2014 and June 2015. The passive-source component of the ENAM-CSE included 30 broadband ocean-bottom seismometers (OBSs) and 3 onshore broadband instruments. The broadband stations were deployed contemporaneously with those of the easternmost EarthScope Transportable Array creating a trans-margin amphibious seismic dataset. The active-source portion of the ENAM-CSE included several components: (1)~two onshore wide-angle seismic profiles where explosive shots were recorded on closely spaced geophones; (2)~four major offshore wide-angle seismic profiles acquired with an airgun source and short-period OBSs (SPOBSs), two of which were extended onland by deployments of short-period seismometers; (3)~marine multichannel seismic (MCS) data acquired along the four lines of SPOBSs and a series of other profiles along and across the margin. During the cruises, magnetic, gravity, and bathymetric data were also collected along all MCS profiles. All of the ENAM-CSE products were made publicly available shortly after acquisition, ensuring unfettered community access to this unique dataset.},
	issn = {0895-0695},
	doi = {10.1785/0220190142},
	url = {https://doi.org/10.1785/0220190142},
	author = {Lynner, Colton and J. A. Van Avendonk, Harm and B{\'e}cel, Anne and Christeson, Gail L. and Dugan, Brandon and Gaherty, James B. and Harder, Steven and Hornbach, Matthew J. and Lizarralde, Daniel and Long, Maureen D. and Magnani, M. Beatrice and Shillington, Donna J. and Aderhold, Kasey and Eilon, Zachary C. and Wagner, Lara S.}
}
@article {warren-smith_episodic_2019,
	title = {Episodic stress and fluid pressure cycling in subducting oceanic crust during slow slip},
	journal = {Nature Geoscience},
	volume = {12},
	number = {6},
	year = {2019},
	note = {Number: 6 Publisher: Nature Publishing Group},
	month = {jun},
	pages = {475{\textendash}481},
	abstract = {Slow slip events are part of a spectrum of aseismic processes that relieve tectonic stress on faults. Their spatial distribution in subduction zones has been linked to perturbations in fluid pressure within the megathrust shear zone and subducting oceanic crust. However, physical observations of temporal fluid pressure fluctuations through slow slip cycles remain elusive. Here, we use earthquake focal mechanisms recorded on an ocean-bottom seismic network to show that crustal stresses and fluid pressures within subducting oceanic crust evolve before and during slow slip events. Specifically, we observe that the retrieved stress ratio, which describes the relative magnitudes of the principal compressive stresses, systematically decreases before slow slip events in New Zealand{\textquoteright}s northern Hikurangi subduction zone, and subsequently increases during the evolution of each slow slip event. We propose that these changes represent the accumulation and release of fluid pressure within overpressured subducting oceanic crust, the episodicity of which may influence the timing of slow slip event occurrence on subduction megathrusts. This work contributes an improved understanding of the physical driving forces underlying slow subduction earthquakes, and a potential means by which to monitor stress and fluid pressure accumulation in such regions.},
	keywords = {seismology, Tectonics},
	issn = {1752-0908},
	doi = {10.1038/s41561-019-0367-x},
	url = {https://www.nature.com/articles/s41561-019-0367-x},
	author = {Warren-Smith, E. and Fry, B. and Wallace, L. and Chon, E. and Henrys, S. and Sheehan, A. and Mochizuki, K. and Schwartz, S. and Webb, S. and Lebedev, S.}
}
@article {Russell2019,
	title = {High-Resolution Constraints on Pacific Upper Mantle Petrofabric Inferred From Surface-Wave Anisotropy},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {124},
	number = {1},
	year = {2019},
	month = {jan},
	pages = {631{\textendash}657},
	issn = {2169-9313},
	doi = {10.1029/2018JB016598},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JB016598},
	author = {Russell, Joshua B. and Gaherty, James B. and Lin, Pei-Ying Patty and Lizarralde, Daniel and Collins, John A. and Hirth, Greg and Evans, Rob L.}
}
@article {Sheehan2019,
	title = {Improving Forecast Accuracy With Tsunami Data Assimilation: The 2009 Dusky Sound, New Zealand, Tsunami},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {124},
	number = {1},
	year = {2019},
	month = {jan},
	pages = {566{\textendash}577},
	issn = {2169-9313},
	doi = {10.1029/2018JB016575},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JB016575},
	author = {Sheehan, Anne F. and Gusman, Aditya R. and Satake, Kenji}
}
@article {smalls_lakebottom_2019,
	title = {Lake-Bottom Seismograph Observations of Microseisms in Yellowstone Lake},
	journal = {Seismological Research Letters},
	volume = {90},
	number = {3},
	year = {2019},
	month = {apr},
	pages = {1200{\textendash}1208},
	abstract = {Ambient-noise records from a seismograph deployed in Yellowstone Lake during July{\textendash}August 2016 contain high-amplitude signals in the 0.4{\textendash}1.1~Hz frequency band, which exhibit strong diurnal variations. These diurnal amplitude variations are highly coherent with wind-speed data from a meteorological station on the lake{\textquoteright}s northern shore, and as the wind builds over the course of a typical summer day, the amplitude and period of the microseism signal progressively increase, consistent with the evolution of a gravity-wave amplitude spectrum. The peak spectral levels are at frequencies of \~{}1.0  Hz, which is roughly twice the peak frequency of a fetch-limited wavefield given the 10{\textendash}19~km fetch to our lake-floor station, suggesting the signals represent double-frequency microseisms. The \~{}3.4  hr lag observed between wind speed and seismic noise levels are consistent with this interpretation.},
	issn = {0895-0695},
	doi = {10.1785/0220180242},
	url = {https://doi.org/10.1785/0220180242},
	author = {Smalls, Paris T. and Sohn, Robert A. and Collins, John A.}
}
@article {Kuna2019,
	title = {Mode of slip and crust{\textendash}mantle interaction at oceanic transform faults},
	journal = {Nature Geoscience},
	volume = {12},
	number = {2},
	year = {2019},
	month = {feb},
	pages = {138{\textendash}142},
	issn = {1752-0894},
	doi = {10.1038/s41561-018-0287-1},
	url = {http://www.nature.com/articles/s41561-018-0287-1},
	author = {Kuna, V{\'a}clav M. and N{\'a}b{\v e}lek, John L. and Braunmiller, Jochen}
}
@article {fredrickson_optimizing_2019,
	title = {Optimizing Sensor Configurations for the Detection of Slow-Slip Earthquakes in Seafloor Pressure Records, Using the Cascadia Subduction Zone as a Case Study},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {124},
	number = {12},
	year = {2019},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2019JB018053},
	pages = {13504{\textendash}13531},
	abstract = {We present seafloor pressure records from the Cascadia Subduction Zone, alongside oceanographic and geophysical models, to evaluate the spatial uniformity of bottom pressure and optimize the geometry of sensor networks for resolving offshore slow-slip transients. Seafloor pressure records from 2011 to 2015 show that signal amplitudes are depth-dependent, with tidally filtered and detrended root-mean-squares of <2 cm on the abyssal plain and >6 cm on the continental shelf. This is consistent with bottom pressure predictions from circulation models and comparable to deformation amplitudes from offshore slow slip observed in other subduction zones. We show that the oceanographic component of seafloor pressure can be reduced to <=1-cm root-mean-square by differencing against a reference record from a similar depth, under restrictions that vary with depth. Instruments at 100{\textendash}250 m require depths matched within 10 m at separations of <100 km, while locations deeper than 1,400 m are broadly comparable over separations of at least 300 km. Despite the significant noise reduction from this method, no slow slip was identified in the dataset, possibly due to poor spatiotemporal instrument coverage, nonideal deployment geometry, and limited depth-matched instruments. We use forward predictions of deformation from elastic half-space models and hindcast pressure from circulation models to generate synthetic slow-slip observational records and show that a range of slip scenarios produce resolvable signals under depth-matched differencing. For future detection of offshore slow slip in Cascadia, we recommend a geometry in which instruments are deployed along isobaths to optimize corrections for oceanographic signals.},
	keywords = {Cascadia Subduction Zone, geodesy, ocean circulation, seafloor pressure, slow-slip earthquake},
	issn = {2169-9356},
	doi = {10.1029/2019JB018053},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JB018053},
	author = {Fredrickson, Erik K. and Wilcock, William S. D. and Schmidt, David A. and MacCready, Parker and Roland, Emily and Kurapov, Alexander L. and Zumberge, Mark A. and Sasagawa, Glenn S.}
}
@article {vanderbeek_pn_2019,
	title = {Pn Tomography of the Juan de Fuca and Gorda Plates: Implications for Mantle Deformation and Hydration in the Oceanic Lithosphere},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {124},
	number = {8},
	year = {2019},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2019JB017707},
	pages = {8565{\textendash}8583},
	abstract = {Tomographic analysis of Pn arrivals{\textemdash}the guided P wave propagating within the lithospheric mantle{\textemdash}is ideal for studying uppermost mantle structure. While plate-scale seismic images of Pn velocities are common beneath the continents, similar scale studies have not been possible within ocean basins due to the sparse distribution of seismic stations. The Cascadia Initiative (CI) data set provides the first opportunity to image spatial variations in lithospheric structure from accretion to subduction across an entire oceanic plate. We invert Pn travel times from local earthquakes for 3-D variations in isotropic and anisotropic P wave velocity and event hypocentral parameters. Despite surficial evidence of extensive faulting, we find that the velocity structure of the Gorda uppermost mantle is remarkably consistent with predictions from a conductive cooling model. Limited brittle deformation at mantle depths is supported by seismic anisotropy measurements, which show the fast direction of P wave propagation rotates in concert with the magnetic anomaly lineations. This rotation may be explained by local plate kinematics without internal deformation and hydration of the shallow mantle. In contrast to Gorda, the seismic velocity structure of the Juan de Fuca (JdF) plate does not exhibit a clear age dependence. Anomalously slow mantle velocities are found along the southern edge of the JdF plate and are spatially associated with the termini of pseudofaults. We attribute these velocity reductions to mantle alteration by seawater. Our results highlight the heterogeneous nature of the oceanic mantle lithosphere and show that patterns of mantle alteration are not readily discerned from surficial indicators of seafloor deformation.},
	keywords = {Cascadia, mantle hydration, oceanic lithosphere, offshore seismicity, Pn tomography, seismic anisotropy},
	issn = {2169-9356},
	doi = {10.1029/2019JB017707},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JB017707},
	author = {VanderBeek, Brandon P. and Toomey, Douglas R.}
}
@article {trehu_post-seismic_2019,
	title = {Post-seismic response of the outer accretionary prism after the 2010 Maule earthquake, Chile},
	journal = {Geosphere},
	volume = {16},
	number = {1},
	year = {2019},
	month = {dec},
	pages = {13{\textendash}32},
	abstract = {To investigate the dynamic response of the outer accretionary prism updip from the patch of greatest slip during the 2010 Mw 8.8 Maule earthquake (Chile), 10 ocean-bottom seismometers (OBSs) were deployed from May 2012 to March 2013 in a small network with an inter-instrument spacing of 7{\textendash}10 km. Nine were recovered, with four recording data from intermediate-band three-component seismometers and differential pressure gauges, and five recording data from absolute pressure gauges (APGs). All instruments were also equipped with fluid flow meters designed to detect very low rates of flow into or out of the seafloor. We present hypocenters for local earthquakes that have S-P times \&lt;17 s (i.e., within \~{}125 km of the network), with a focus on events located beneath or near the network. Most of the seismicity occurred either near the boundary between the active accretionary prism and continental basement or in the outer rise seaward of the trench. For many outer-rise earthquakes, the P and S arrivals are followed by a distinctive T-phase arrival. Very few earthquakes, and none located with hypocenters deemed {\textquotedblleft}reliable,{\textquotedblright} were located within the active accretionary prism or on the underlying plate boundary. Nonvolcanic tremor-like pulses and seafloor pressure transients (but no very-low-frequency earthquakes or fluid flow) were also detected. Many of the tremor observations are likely T-phases or reverberations due to soft seafloor sediments, although at least one episode may have originated within the accretionary prism south of the network. The transient seafloor pressure changes were observed simultaneously on three APGs located over the transition from the active prism to the continental basement and show polarity changes over short distances, suggesting a shallow source. Their duration of several hours to days is shorter than most geodetic transients observed using onshore GPS networks. The results demonstrate the need for densely spaced and large-aperture OBS networks equipped with APGs for understanding subduction zone behavior.},
	issn = {1553-040X},
	doi = {10.1130/GES02102.1},
	url = {https://doi.org/10.1130/GES02102.1},
	author = {Tr{\'e}hu, Anne M. and de Moor, Alexander and Madrid, Jos{\'e} Mieres and S{\'a}ez, Miguel and Chadwell, C. David and Ortega-Culaciati, Francisco and Ruiz, Javier and Ruiz, Sergio and Tryon, Michael D.}
}
@article {shuck_role_2019,
	title = {The role of mantle melts in the transition from rifting to seafloor spreading offshore eastern North America},
	journal = {Earth and Planetary Science Letters},
	volume = {525},
	year = {2019},
	month = {nov},
	pages = {115756},
	abstract = {The Eastern North American Margin (ENAM) formed in the early Jurassic (\~{}195 Ma) with the breakup of supercontinent Pangea. This rifting event was accompanied by volcanism along the continental shelf of the eastern United States, giving rise to the East Coast Magnetic Anomaly (ECMA). Numerical models show that magmatic diking can assist rifting by reducing the effective stress required to rupture the lithosphere. Therefore, magma-rich rifts can develop a rapid transition from continental breakup to seafloor spreading. Alternatively, the onset of seafloor spreading may be accompanied by a long period of persistent thermal weakening and erosion of the lithosphere. In this paper we present analyses of active-source wide-angle seismic data collected during the 2014 ENAM Community Seismic Experiment in an area that extends farther offshore than previous seismic surveys along the eastern U.S. Seaward of the ECMA lies a zone of thin oceanic crust with high compressional seismic velocity (up to 7.5 km/s in the lower crust), whereas thicker normal oceanic crust lies \~{}200 km farther offshore along another prominent magnetic anomaly, the Blake Spur Magnetic Anomaly (BSMA). We reconcile our seismic images with a petrologic model to evaluate the mantle melting conditions during the late stages of continental breakup and early seafloor spreading in the Central Atlantic. We propose that the zone of thin crust between the ECMA and BSMA with high seismic velocity is best explained by the presence of a \~{}15{\textendash}20 km thick lithospheric lid at the time of early seafloor spreading, which prevented melting in the shallow mantle. Our analysis suggests that the volcanism that produced the nearshore ECMA did not lead to complete lithospheric breakup of the conjugate North American and African margins. Normal seafloor spreading began at the BSMA under a moderately high mantle potential temperature of \~{}1395{\textendash}1420{\textdegree}C, \~{}25 million years after the initial formation of the volcanic margin. These results imply that stretching, thermal weakening, and rupture of the lithosphere may take millions of years, even in the presence of mantle melts.},
	keywords = {continent-ocean transition, continental rifting, eastern North American margin, mantle melting, oceanic crust, seismic tomography},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2019.115756},
	url = {https://www.sciencedirect.com/science/article/pii/S0012821X19304480},
	author = {Shuck, Brandon D. and Van Avendonk, Harm J. A. and B{\'e}cel, Anne}
}
@article {Arnoux2019,
	title = {Seismic Imaging and Physical Properties of the Endeavour Segment: Evidence that Skew Between Mantle and Crustal Magmatic Systems Governs Spreading Center Processes},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {20},
	number = {3},
	year = {2019},
	month = {mar},
	pages = {1319{\textendash}1339},
	issn = {1525-2027},
	doi = {10.1029/2018GC007978},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GC007978},
	author = {Arnoux, G. M. and Toomey, D. R. and Hooft, E. E. E. and Wilcock, W. S. D.}
}
@article {Hooft2019,
	title = {Seismic imaging of Santorini: Subsurface constraints on caldera collapse and present-day magma recharge},
	journal = {Earth and Planetary Science Letters},
	volume = {514},
	year = {2019},
	month = {may},
	pages = {48{\textendash}61},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2019.02.033},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X19301360},
	author = {Hooft, E.E.E. and Heath, B.A. and Toomey, D.R. and Paulatto, M. and Papazachos, C.B. and Nomikou, P. and Morgan, J.V. and Warner, M.R.}
}
@article {doran_seismic_2019,
	title = {Seismic Structure of Marine Sediments and Upper Oceanic Crust Surrounding Hawaii},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {124},
	number = {2},
	year = {2019},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2018JB016548},
	pages = {2038{\textendash}2056},
	abstract = {We present models of compressional and shear velocity structure of the oceanic sediments and upper crust surrounding the Hawaiian islands. The models were derived from analysis of seafloor compliance data and measurements of Ps converted phases originating at the sediment-bedrock interface. These data were estimated from continuous broadband ocean bottom seismometer acceleration and pressure records collected during the Plume-Lithosphere Undersea Mantle Experiment, an amphibious array of wideband and broadband instruments with an aperture of over 1,000 km. Our images result from a joint inversion of compliance and Ps delay data using a nonlinear inversion scheme whereby deviation from a priori constraints is minimized. In our final model, sediment thickness increases from 50 m at distal sites to over 1.5 km immediately adjacent to the islands. The sedimentary shear velocity profiles exhibit large regional variations. While sedimentary structure accounts for the majority of the compliance signal, we infer variations in shear velocity in the uppermost bedrock on the order of {\textpm}5\%. We also require relatively high values of Poisson{\textquoteright}s ratio in the uppermost crust. Lower crustal velocities are generally seen to the north and west of the islands but do not appear well correlated with the Hawaiian Swell bathymetry. A region of strong low velocity anomalies to the northeast of Hawaii may be associated with the Molokai fracture zone.},
	issn = {2169-9356},
	doi = {10.1029/2018JB016548},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JB016548},
	author = {Doran, A. K. and Laske, G.}
}
@article {merz_seismicity_2019,
	title = {Seismicity and Velocity Structure of Lo{\textquoteright}ihi Submarine Volcano and Southeastern Hawai{\textquoteright}i},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {124},
	number = {11},
	year = {2019},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2019JB018168},
	pages = {11380{\textendash}11393},
	abstract = {Hundreds of earthquakes were recorded during a nine-month ocean bottom seismometer deployment surrounding Lo{\textquoteright}ihi submarine volcano, Hawai{\textquoteright}i. The 12-station ocean bottom seismometer network widened the aperture of earthquake detection around the Big Island, allowing better constraints on the location of seismicity offshore Hawai{\textquoteright}i. Although this deployment occurred during a time of volcanic quiescence for Lo{\textquoteright}ihi, it establishes an important basis for background seismicity of the volcano. Offshore seismicity during this study was dominated by events located in the mantle fault zone at depths of 25{\textendash}40 km. These events reflect rupture on preexisting faults in the lower lithosphere caused by stresses induced by volcano loading and flexure of the Pacific Plate (Pritchard et al., 2007, https://doi.org/10.1111/j.1365-246X.2006.03169.x; Wolfe et al., 2004, https://doi.org/10.1029/2003GC000618). Tomography was performed using double-difference seismic tomography and showed shallow velocities to be slower than the regional velocity model (HG50; Klein, 1981, https://pubs.geoscienceworld.org/ssa/bssa/article/71/5/1503/118231/A-linear-gradient-crustal-model-for-south-Hawaii). A broad, low-velocity anomaly was observed from 20{\textendash}40-km depth, and is suggestive of the central plume conduit that supplies magma to Lo{\textquoteright}ihi and the active volcanoes of the Big Island. A localized high-velocity body is observed 4{\textendash}6-km depth beneath Lo{\textquoteright}ihi{\textquoteright}s summit, extending 10 km to the north and south. Following Lo{\textquoteright}ihi{\textquoteright}s active rift zones and crossing the summit, this high-velocity body is characteristic of intrusive material. Two low-velocity anomalies are observed below the oceanic crust, interpreted as melt accumulation beneath Lo{\textquoteright}ihi and magmatic underplating beneath Hawai{\textquoteright}i Island.},
	keywords = {Hawai{\textquoteright}i, hot spot, Lo{\textquoteright}ihi seamount, tomography, volcano seismology},
	issn = {2169-9356},
	doi = {10.1029/2019JB018168},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JB018168},
	author = {Merz, D. K. and Caplan-Auerbach, J. and Thurber, C. H.}
}
@article {yarce_seismicity_2019,
	title = {Seismicity at the Northern Hikurangi Margin, New Zealand, and Investigation of the Potential Spatial and Temporal Relationships With a Shallow Slow Slip Event},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {124},
	number = {5},
	year = {2019},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2018JB017211},
	pages = {4751{\textendash}4766},
	abstract = {In 2014{\textendash}2015, the Hikurangi Ocean Bottom Investigation of Tremor and Slow Slip experiment deployed seafloor absolute pressure gauges and ocean bottom seismometers directly above a large slow slip event, allowing examination of the relationship between slow slip and earthquakes in detail. Hikurangi Ocean Bottom Investigation of Tremor and Slow Slip data were combined with nearby existing land stations to create a catalog of microseismicity consisting of 2,300 earthquakes ranging in magnitude between 0.5 and 4.7 that is complete to magnitude 1.5, yielding almost twice as many events as detected by the onshore networks alone. This greatly improves the seismicity catalog for this active subduction zone margin, especially in the offshore portion that was difficult to study using only the inland permanent seismic network. The new locations for the events within the footprint of the offshore network show that earthquakes near the trench are systematically shallower than and NW (landward) of their locations using only land-based stations. Our results indicate that Hikurangi seismicity is concentrated in two NE-SW bands, one offshore beneath the outer forearc wedge, one onshore beneath the eastern Raukumara Peninsula, and the majority of earthquakes are within the subducting Pacific plate with a smaller percent at the plate interface. We find a 20-km wide northeast trending gap in microseismicity between the two bands and beneath the inner forearc wedge and this gap in seismicity borders the downdip edge of a slow slip patch.},
	keywords = {gap, Hikurangi, ocean bottom seismometers, seismicity, slow slip},
	issn = {2169-9356},
	doi = {10.1029/2018JB017211},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JB017211},
	author = {Yarce, J. and Sheehan, A. F. and Nakai, J. S. and Schwartz, S. Y. and Mochizuki, K. and Savage, M. K. and Wallace, L. M. and Henrys, S. A. and Webb, S. C. and Ito, Y. and Abercrombie, R. E. and Fry, B. and Shaddox, H. and Todd, E. K.}
}
@article {williams_stress_2019,
	title = {Stress Drops on the Blanco Oceanic Transform Fault from Interstation Phase Coherence},
	journal = {Bulletin of the Seismological Society of America},
	volume = {109},
	number = {3},
	year = {2019},
	pages = {929{\textendash}943},
	abstract = {Oceanic transform faults display a wide range of earthquake stress drops, large aseismic slip, and along-strike variation in seismic coupling. We use and further develop a phase coherence-based method to calculate and analyze stress drops of 61 M>=5.0 events between 2000 and 2016 on the Blanco fault, off the coast of Oregon. With this method, we estimate earthquake rupture extents by examining how apparent source time functions (ASTFs) vary between stations. The variation is caused by the generation of seismic waves at different locations along the rupture, which arrive at different times depending on station location. We isolate ASTFs at a range of stations by comparing seismograms of collocated earthquakes and then use the interstation ASTF coherence to infer rupture extent and stress drop.We examine how our analysis is influenced by various factors, including poor trace alignment, relative earthquake locations, focal mechanism variation, azimuthal distribution of stations, and depth phase arrivals. We find that as alignment accuracy decreases or distance between earthquakes increases, coherence is reduced, but coherence is unaffected by focal mechanism variation or depth phase arrivals for our dataset. We calibrate the coherence{\textendash}rupture extent relationship based on the azimuthal distribution of stations.We find the phase coherence method can be used to estimate stress drops for offshore earthquakes, but is limited to M>=5.0 earthquakes for the Blanco fault due to poor trace alignment accuracy. The median stress drop on the Blanco fault is 8~MPa (with 95\% confidence limits of 6{\textendash}12~MPa) for 61 earthquakes. Stress drops are a factor of 1.7 (95\% confidence limits 0.8{\textendash}3.5) lower on the more aseismic northwest segment of the Blanco fault. These lower stress drops could be linked to reduced healing time due to higher temperatures, which reduce the depth of the seismogenic zone and shorten the seismic cycle.},
	issn = {0037-1106},
	doi = {10.1785/0120180319},
	url = {https://doi.org/10.1785/0120180319},
	author = {Williams, Joshua R. and Hawthorne, Jessica C. and Rost, Sebastian and Wright, Tim J.}
}
@article {shaddox_subducted_2019,
	title = {Subducted seamount diverts shallow slow slip to the forearc of the northern Hikurangi subduction zone, New Zealand},
	journal = {Geology},
	volume = {47},
	number = {5},
	year = {2019},
	month = {mar},
	pages = {415{\textendash}418},
	abstract = {Fluid migration and pore fluid pressure have been implicated in generating the transitional fault zone properties thought to be important for slow slip events (SSEs) in subduction zones. At the northern Hikurangi margin, New Zealand, overpressurized sediments spatially correlated with shallow SSEs are imaged downdip of subducted seamounts, providing an excellent environment to study the relationship between subducted oceanic relief, fluids, shallow SSEs, and related microseismicity. Using data from ocean-bottom seismometers, we detect {\textquotedblleft}burst-type{\textquotedblright} repeating earthquakes coincident with tremor on an upper-plate fracture network above a subducted seamount. This activity occurred at the edge of a large, shallow SSE recorded offshore of Gisborne, New Zealand, in September{\textendash}October 2014, but began days to weeks after the SSE and continued for nearly two months. We propose that during the large plate-boundary SSE, fluids migrated from the downdip overpressurized sediments into the fracture network, diverting aseismic slip to multiple faults in the upper plate. Thus, seamount subduction appears to play a key role in controlling the mechanics of shallow slow slip and microseismicity at the northern Hikurangi margin.},
	issn = {0091-7613},
	doi = {10.1130/G45810.1},
	url = {https://doi.org/10.1130/G45810.1},
	author = {Shaddox, Heather R. and Schwartz, Susan Y.}
}
@article {Isse2019,
	title = {Surface wave tomography for the Pacific Ocean incorporating seafloor seismic observations and plate thermal evolution},
	journal = {Earth and Planetary Science Letters},
	volume = {510},
	year = {2019},
	month = {mar},
	pages = {116{\textendash}130},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2018.12.033},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X19300032},
	author = {Isse, Takehi and Kawakatsu, Hitoshi and Yoshizawa, Kazunori and Takeo, Akiko and Shiobara, Hajime and Sugioka, Hiroko and Ito, Aki and Suetsugu, Daisuke and Reymond, Dominique}
}
@article {Heath2019,
	title = {Tectonism and Its Relation to Magmatism Around Santorini Volcano From Upper Crustal P Wave Velocity},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {124},
	number = {10},
	year = {2019},
	month = {oct},
	pages = {10610{\textendash}10629},
	issn = {2169-9313},
	doi = {10.1029/2019JB017699},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JB017699},
	author = {Heath, B. A. and Hooft, E. E. E. and Toomey, D. R. and Papazachos, C. B. and Nomikou, P. and Paulatto, M. and Morgan, J. V. and Warner, M. R.}
}
@article {stephen_three-dimensional_2019,
	title = {Three-dimensional bottom diffraction in the North Pacific},
	journal = {The Journal of the Acoustical Society of America},
	volume = {146},
	number = {3},
	year = {2019},
	note = {Publisher: Acoustical Society of America},
	pages = {1913{\textendash}1922},
	abstract = {A significant aspect of bottom-interaction in deep water acoustic propagation, from point sources to point receivers, is the diffraction (or scattering) of energy from discrete seafloor locations along repeatable, deterministic paths in three-dimensions. These bottom-diffracted surface-reflected (BDSR) paths were first identified on the North Pacific acoustic laboratory experiment in 2004 (NPAL04) for a diffractor located on the side of a small seamount. On the adjacent deep seafloor, ambient noise and propagation in the ocean sound channel were sufficiently quiet that the BDSRs were the dominant arrival. The ocean bottom seismometer augmentation in the North Pacific (OBSANP) experiment in June{\textendash}July 2013 studied BDSRs at the NPAL04 site in more detail. BDSRs are most readily identified by the arrival time of pulses as a function of range to the receiver for a line of transmissions. The diffraction points for BDSRs occur on the relatively featureless deep seafloor as well as on the sides of small seamounts. Although the NPAL04 and OBSANP experiments had very different geometries the same diffractor location is consistent with observed arrivals in both experiments within the resolution of the analysis. On OBSANP the same location excites BDSRs for 77.5, 155, and 310 Hz transmissions.},
	issn = {0001-4966},
	doi = {10.1121/1.5125427},
	url = {https://asa.scitation.org/doi/full/10.1121/1.5125427},
	author = {Stephen, Ralph A. and Bolmer, S. Thompson and Worcester, Peter F. and Dzieciuch, Matthew A. and Udovydchenkov, Ilya A.}
}
@article {wang_tsunami_2019,
	title = {Tsunami Data Assimilation Without a Dense Observation Network},
	journal = {Geophysical Research Letters},
	volume = {46},
	number = {4},
	year = {2019},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2018GL080930},
	pages = {2045{\textendash}2053},
	abstract = {The tsunami data assimilation method enables tsunami forecasting directly from observations, without the need of estimating tsunami sources. However, it requires a dense observation network to produce desirable results. Here we propose a modified method of tsunami data assimilation for regions with a sparse observation network. The method utilizes interpolated waveforms at virtual stations. The tsunami waveforms at the virtual stations between two existing observation stations are estimated by shifting arrival times with the linear interpolation of observed arrival times and by correcting the amplitudes for their water depths. In our new data assimilation approach, we employ the Optimal Interpolation algorithm to both the real observations and virtual stations, in order to construct a complete wavefront of tsunami propagation. The application to the 2004 Sumatra-Andaman earthquake and the 2009 Dusky Sound, New Zealand, earthquake reveals that addition of virtual stations greatly helps improve the tsunami forecasting accuracy.},
	keywords = {data assimilation, tsunami forecasting},
	issn = {1944-8007},
	doi = {10.1029/2018GL080930},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GL080930},
	author = {Wang, Y. and Maeda, T. and Satake, K. and Heidarzadeh, M. and Su, H. and Sheehan, A. F. and Gusman, A. R.}
}
@article {pavlis_unified_2019,
	title = {A unified three-dimensional model of the lithospheric structure at the subduction corner in southeast Alaska: Summary results from STEEP},
	journal = {Geosphere},
	volume = {15},
	number = {2},
	year = {2019},
	month = {jan},
	pages = {382{\textendash}406},
	abstract = {We merge structural results from the ST. Elias Erosion/tectonics Project (STEEP), other studies, and seismicity data to build a comprehensive, three-dimensional model of the lithosphere of the subduction corner in southern Alaska. The model is defined by three surfaces: (1) a top of the subducting lithosphere surface, (2) Moho surfaces, and (3) a base of subducting lithosphere surface. We model the eastern edge of the subducting lithosphere using the southern tip of the Yakutat microplate as an anchor. Kinematic reconstructions using that anchor suggest the modern Fairweather fault is likely inherited from motion of the margin in the 6{\textendash}10 Ma period. We constructed a 4D kinematic model of crustal deformation in the vicinity of Mount St. Elias. We call this model the middlebuster model because the geometry is similar to a two-sided plow with that name. The west side of the plow is the eastern limit of the Aleutian megathrust constructed from the union of constraints from STEEP seismic results and slip models of the 1979 St. Elias earthquake. The east side is inferred from geologic mapping and slip models of the 1899 Yakutat Bay earthquake sequence. The top of the plow is near the Seward Glacier, where previous studies showed near world-record exhumation rates. GPS velocity vectors show a large rotation across the syntaxis at Mount St. Elias. West of the syntaxis, faults inferred from inversion of the GPS data are above the megathrust inferred from seismic imaging. That and other evidence suggest the presence of a wedge of ductile crust that partially decouples the subducting mantle lithosphere from the upper crust in the area near the suture with the Yakutat microplate.},
	issn = {1553-040X},
	doi = {10.1130/GES01488.1},
	url = {https://doi.org/10.1130/GES01488.1},
	author = {Pavlis, Gary L. and Bauer, Mark A. and Elliott, Julie L. and Koons, Peter and Pavlis, Terry L. and Ruppert, Natalia and Ward, Kevin M. and Worthington, Lindsay L.}
}
@article {krischer_automated_2018,
	title = {Automated Large-Scale Full Seismic Waveform Inversion for North America and the North Atlantic},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {123},
	number = {7},
	year = {2018},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2017JB015289},
	pages = {5902{\textendash}5928},
	abstract = {We present a new anisotropic seismic tomography model based on a multiscale full seismic waveform inversion for crustal and upper-mantle structure from the western edge of North America across the North Atlantic and into Europe. The gradient-based inversion strategy utilizes the adjoint state method coupled with an L-BFGS quasi-Newton optimization scheme. To improve the handling of large data quantities in the context of full seismic waveform inversions, we developed a workflow framework automating the procedure across all stages, enabling us to confidently invert for waveforms from 72 events recorded at 7,737 unique stations, resulting in a total of 144,693 raypaths, most of them with three-component recordings. The final model after 20 iterations is able to explain complete waveforms including body as well as surface waves of earthquakes that were not used in the inversion down to periods of around 30 s. The model is complemented by a detailed resolution analysis in the form of 3-D distributions of direction-dependent resolution lengths.},
	keywords = {data management, full-waveform inversion, inverse problems, optimization, seismology, workflow},
	issn = {2169-9356},
	doi = {10.1029/2017JB015289},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2017JB015289},
	author = {Krischer, Lion and Fichtner, Andreas and Boehm, Christian and Igel, Heiner}
}
@article {Bodmer2018,
	title = {Buoyant Asthenosphere Beneath Cascadia Influences Megathrust Segmentation},
	journal = {Geophysical Research Letters},
	volume = {45},
	number = {14},
	year = {2018},
	month = {jul},
	pages = {6954{\textendash}6962},
	issn = {0094-8276},
	doi = {10.1029/2018GL078700},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GL078700},
	author = {Bodmer, Miles and Toomey, Douglas R. and Hooft, Emilie E. E. and Schmandt, Brandon}
}
@article {Gomberg2018,
	title = {Cascadia Onshore-Offshore Site Response, Submarine Sediment Mobilization, and Earthquake Recurrence},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {123},
	number = {2},
	year = {2018},
	month = {feb},
	pages = {1381{\textendash}1404},
	issn = {21699313},
	doi = {10.1002/2017JB014985},
	url = {http://doi.wiley.com/10.1002/2017JB014985},
	author = {Gomberg, J.}
}
@article {Stone2018,
	title = {Catalog of Offshore Seismicity in Cascadia: Insights Into the Regional Distribution of Microseismicity and its Relation to Subduction Processes},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {123},
	number = {1},
	year = {2018},
	month = {jan},
	pages = {641{\textendash}652},
	issn = {21699313},
	doi = {10.1002/2017JB014966},
	url = {http://doi.wiley.com/10.1002/2017JB014966},
	author = {Stone, Ian and Vidale, John E. and Han, Shuoshuo and Roland, Emily}
}
@article {li_connections_2018,
	title = {Connections between subducted sediment, pore-fluid pressure, and earthquake behavior along the Alaska megathrust},
	journal = {Geology},
	volume = {46},
	number = {4},
	year = {2018},
	month = {02/2018},
	pages = {299{\textendash}302},
	abstract = {Variations in pore-fluid pressure along subduction megathrusts are often invoked to explain differences in fault slip behavior between margins. However, many other parameters vary between subduction zones, making it difficult to isolate the causes of elevated pore fluid pressures and their effects on megathrust behavior. Here we show evidence from pre-stack depth migrations of multichannel seismic reflection data along the subduction zone off the Alaska Peninsula for significant, systematic along-strike variations in the thickness, continuity, P-wave velocity, and estimated pore-fluid pressure of the subducting sediment layer that lines the shallow plate interface within 25 km of the trench. These variations appear to correlate with changes in seismicity, locking, and earthquake rupture history. The currently locked and seismically quiet Semidi segment has a continuous, thick (600{\textendash}900 m) subducted sediment layer that is characterized by low seismic velocities and elevated pore pressure (λ* ≈ 0.4{\textendash}0.8). The subducted sediment in the neighboring Shumagin Gap, a region with low geodetic coupling and abundant small earthquakes, is thinner, irregular and has lower pore pressure (λ* \&lt; 0.2{\textendash}0.3). We suggest that the thicker and weakly faulted sediment layer entering the trench at Semidi is associated with a continuous and overpressured sediment layer lining the shallow plate interface, but forms a large coherent asperity as it dewaters and consolidates at greater depths, thus favoring large earthquakes. In contrast, thinner incoming sediment disrupted by outer rise faulting at Shumagin results in a plate interface without elevated pore-fluid pressures, but which is heterogeneous and complex at all depths, contributing to creep and frequent small earthquakes.},
	issn = {0091-7613},
	doi = {10.1130/G39557.1},
	url = {https://doi.org/10.1130/G39557.1},
	author = {Li, Jiyao and Shillington, Donna J. and Saffer, Demian M. and B{\'e}cel, Anne and Nedimovi{\'c}, Mladen R. and Kuehn, Harold and Webb, Spahr C. and Keranen, Katie M. and Abers, Geoffrey A.}
}
@article {Accardo2018,
	title = {Constraints on Rift Basin Structure and Border Fault Growth in the Northern Malawi Rift From 3-D Seismic Refraction Imaging},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {123},
	number = {11},
	year = {2018},
	month = {nov},
	pages = {10,003{\textendash}10,025},
	issn = {21699313},
	doi = {10.1029/2018JB016504},
	url = {http://doi.wiley.com/10.1029/2018JB016504},
	author = {Accardo, N. J. and Shillington, D. J. and Gaherty, J. B. and Scholz, C. A. and Nyblade, A. A. and Chindandali, P. R. N. and Kamihanda, G. and McCartney, T. and Wood, D. and Wambura Ferdinand, R.}
}
@article {todd_earthquakes_2018,
	title = {Earthquakes and Tremor Linked to Seamount Subduction During Shallow Slow Slip at the Hikurangi Margin, New Zealand},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {123},
	number = {8},
	year = {2018},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2018JB016136},
	pages = {6769{\textendash}6783},
	abstract = {Shallow slow slip events have been well documented offshore Gisborne at the northern Hikurangi subduction margin, New Zealand, and are associated with tectonic tremor downdip of the slow slip patch and increases in local microseismicity. Tremor and seismicity on the shallow subduction interface are often poorly resolved due to their distance from land-based seismic and geodetic networks. To address this shortcoming, the Hikurangi Ocean Bottom Investigation of Tremor and Slow Slip experiment deployed 24 absolute pressure gauges and 15 ocean bottom seismometers on the seafloor above the Gisborne slow slip patch to investigate the spatial and temporal extent of slow slip and associated tremor and earthquake activity. We present a detailed spatiotemporal analysis of the seismic signatures of various interplate slip processes associated with the September/October 2014 Gisborne slow slip event. Tectonic tremor begins toward the end and continues after the geodetically constrained slow slip event and is localized in the vicinity of two subducted seamounts within and updip of the slow slip patch. The subsequent, rather than synchronous occurrence of tremor suggests that tremor may be triggered by stress changes induced by slow slip. However, Coulomb failure stress change models based on the slow slip distribution fail to predict the location of tremor, suggesting that seamount subduction plays a dominant role in the stress state of the shallow megathrust. This and the observed interplay of seismic and aseismic interplate slip processes imply that stress changes from slow slip play a secondary role in the distribution of associated microseismicity.},
	keywords = {earthquake, New Zealand, Seamount, slow slip, subduction, tremor},
	issn = {2169-9356},
	doi = {10.1029/2018JB016136},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JB016136},
	author = {Todd, Erin K. and Schwartz, Susan Y. and Mochizuki, Kimihiro and Wallace, Laura M. and Sheehan, Anne F. and Webb, Spahr C. and Williams, Charles A. and Nakai, Jenny and Yarce, Jefferson and Fry, Bill and Henrys, Stuart and Ito, Yoshihiro}
}
@article {261,
	title = {Gas hydrate quantification using full-waveform inversion of sparse ocean-bottom seismic data: A case study from Green Canyon Block 955, Gulf of Mexico},
	journal = {GEOPHYSICS},
	volume = {83},
	year = {2018},
	month = {07/2018},
	pages = {B167{\textendash}B181},
	abstract = {We present a case study of gas hydrate quantification using dense short-offset multichannel seismic (MCS) and sparse long-offset ocean-bottom-seismometer (OBS) data in lease block Green Canyon 955 (GC955), Gulf of Mexico (GOM), where the presence of gas hydrate was interpreted using logging while drilling (LWD) data acquired by the GOM Gas Hydrate Joint Industry Project Leg II expedition. We use frequency-domain full-waveform inversion (FWI) of seven OBS gathers to invert for a P-wave velocity model of an approximately 7 km long MCS profile connecting two LWD sites, GC955-H and GC955-Q. We build the starting model for FWI using traveltime inversion (TI) of the MCS and OBS data. In addition, we use the TI model for depth migrating the MCS stack. At the LWD sites, we constrain the hydrate saturation (Sgh ) using sonic and resistivity logs. Unfortunately, as is typical of seismic quantification problems, the FWI model resolution is not sufficient to extrapolate the LWD-based Sgh . Therefore, we apply Backus averaging to the sonic log, at 60 m wavelength, bringing it within approximately 8\% of the FWI model and make the assumption that averaging the sonic log is same as redistributing the gas hydrate within the Backus wavelength. In this manner, instead of Sgh , the FWI model is able to estimate the total gas hydrate volume. In the end, we use the FWI model and the migrated stack to constrain the locations and bulk volumes of free gas and gas hydrate. Our results demonstrate that with careful processing, reasonable estimates on locations and bulk volumes of submarine gas hydrate accumulations can be achieved even with sparse seismic data that are not adequate for amplitude-based assessments.},
	keywords = {full-waveform inversion, hydrates, ocean-bottom node},
	issn = {0016-8033},
	doi = {10.1190/geo2017-0414.1},
	url = {https://library.seg.org/doi/10.1190/geo2017-0414.1},
	author = {Wang, Jiliang and Jaiswal, Priyank and Haines, Seth S. and Hart, Patrick E. and Wu, Shiguo}
}
@article {Gong2018,
	title = {Interactions between strike-slip earthquakes and the subduction interface near the Mendocino Triple Junction},
	journal = {Earth and Planetary Science Letters},
	volume = {482},
	year = {2018},
	month = {jan},
	pages = {414{\textendash}422},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2017.11.022},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X17306581},
	author = {Gong, Jianhua and McGuire, Jeffrey J.}
}
@article {Horning2018,
	title = {Local Seismicity of the Rainbow Massif on the Mid-Atlantic Ridge},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {123},
	number = {2},
	year = {2018},
	month = {feb},
	pages = {1615{\textendash}1630},
	issn = {21699313},
	doi = {10.1002/2017JB015288},
	url = {http://doi.wiley.com/10.1002/2017JB015288},
	author = {Horning, G. and Sohn, R. A. and Canales, J. P. and Dunn, R. A.}
}
@article {Lim2018,
	title = {Measurement of seismometer orientation using the tangential P-wave receiver function based on harmonic decomposition},
	journal = {Geophysical Journal International},
	volume = {212},
	number = {3},
	year = {2018},
	month = {mar},
	pages = {1747{\textendash}1765},
	issn = {0956-540X},
	doi = {10.1093/gji/ggx515},
	url = {http://academic.oup.com/gji/article/212/3/1747/4705902},
	author = {Lim, Hobin and Kim, YoungHee and Song, Teh-Ru Alex and Shen, Xuzhang}
}
@mastersthesis {2018PhDT.........1J,
	title = {New Insights on the Structure of the Cascadia Subduction Zone from Amphibious Seismic Data},
	year = {2018},
	month = {jan},
	school = {Columbia University},
	type = {phdPh.D.},
	keywords = {Geophysics, Plate tectonics},
	author = {Janiszewski, Helen Anne}
}
@article {morton_newly_2018,
	title = {Newly detected earthquakes in the Cascadia subduction zone linked to seamount subduction and deformed upper plate},
	journal = {Geology},
	volume = {46},
	number = {11},
	year = {2018},
	month = {09/2018},
	pages = {943{\textendash}946},
	abstract = {Data from an amphibious seismic network in Cascadia (northwest North America) provide unique near-source observations to assess the influence of subducting topography on seismicity. Using subspace detection, we detect and locate 222 events in two separate clusters, near a subducted seamount and a possibly accreted seamount. Seismicity in both clusters is largely shallower than the plate interface and exhibits occasional swarm-like behavior. This implies that the seamount is subducting aseismically via weak coupling with the overriding plate, while earthquakes in the upper plate arise from a high degree of fracturing due to seamount interaction, and the accreted seamount induced similar fracturing before off-scraping.},
	issn = {0091-7613},
	doi = {10.1130/G45354.1},
	url = {https://doi.org/10.1130/G45354.1},
	author = {Morton, Emily A. and Bilek, Susan L. and Rowe, Charlotte A.}
}
@article {Wei2018,
	title = {P-wave attenuation structure of the Lau back-arc basin and implications for mantle wedge processes},
	journal = {Earth and Planetary Science Letters},
	volume = {502},
	year = {2018},
	month = {nov},
	pages = {187{\textendash}199},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2018.09.005},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X18305363},
	author = {Wei, S. Shawn and Wiens, Douglas A.}
}
@article {agius_sediment_2018,
	title = {Sediment Characterization at the Equatorial Mid-Atlantic Ridge From P-to-S Teleseismic Phase Conversions Recorded on the PI-LAB Experiment},
	journal = {Geophysical Research Letters},
	volume = {45},
	number = {22},
	year = {2018},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2018GL080565},
	month = {11/2018},
	pages = {12,244{\textendash}12,252},
	abstract = {Accurate marine sediment characteristics, for example, thickness and seismic velocity, are important for constraining sedimentation rates with implications for climate variations and for seismic imaging of deeper structures using ocean bottom seismic deployments. We analyze P-to-S seismic phase conversions from the sediment-crust boundary recorded by the Passive Imaging of the Lithosphere-Asthenosphere Boundary (PI-LAB) experiment to infer the sediment thickness across the Mid-Atlantic Ridge covering 0- to 80-Myr-old seafloor. We find Pds-P delay times of 0.04{\textendash}0.37 s, or 5- to 82-m thickness. Sediment thickness increases with age. Thickness agrees with global estimates for young (<15{\textendash}20 Myr) seafloor but is thinner on older lithosphere. Our result may represent a lower limit on sediment thickness, given that several of our stations are on topographic highs. The sedimentation rate decrease observed from 5 to 1.2 mm/kyr at \~{}10 Myr suggests a recent increase in productivity related to climate change, eolian dust fluxes, and/or biogenic marine activity.},
	keywords = {equatorial Mid-Atlantic Ridge, PI-LAB, sediments},
	issn = {1944-8007},
	doi = {10.1029/2018GL080565},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GL080565},
	author = {Agius, M. R. and Harmon, N. and Rychert, C. A. and Tharimena, S. and Kendall, J.-M.}
}
@article {Ruan2018,
	title = {Shear attenuation beneath the Juan de Fuca plate: Implications for mantle flow and dehydration},
	journal = {Earth and Planetary Science Letters},
	volume = {496},
	year = {2018},
	month = {aug},
	pages = {189{\textendash}197},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2018.05.035},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X18303182},
	author = {Ruan, Youyi and Forsyth, Donald W. and Bell, Samuel W.}
}
@article {moyer_spatial_2018,
	title = {Spatial and Temporal Variations in Earthquake Stress Drop on Gofar Transform Fault, East Pacific Rise: Implications for Fault Strength},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {123},
	number = {9},
	year = {2018},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2018JB015942},
	pages = {7722{\textendash}7740},
	abstract = {On Gofar Transform Fault on the East Pacific Rise, the largest earthquakes (6.0 <= MW <= 6.2) have repeatedly ruptured the same portion of the fault, while intervening fault segments host swarms of microearthquakes. These long-term patterns in earthquake occurrence suggest that heterogeneous fault zone properties control earthquake behavior. Using waveforms from ocean bottom seismometers that recorded seismicity before and after an anticipated 2008 MW 6.0 mainshock, we investigate the role that differences in material properties have on earthquake rupture at Gofar. We determine stress drop for 138 earthquakes (2.3 <= MW <= 4.0) that occurred within and between the rupture areas of large earthquakes. Stress drops are calculated from corner frequencies derived using an empirical Green{\textquoteright}s function spectral ratio method, and seismic moments are obtained by fitting the omega-square source model to the low frequency amplitude of the displacement spectrum. Our analysis yields stress drops from 0.04 to 3.2 MPa with statistically significant spatial variation, including 2 times higher average stress drop in fault segments where large earthquakes also occur compared to fault segments that host earthquake swarms. We find an inverse correlation between stress drop and P wave velocity reduction, which we interpret as the effect of fault zone damage on the ability of the fault to store strain energy that leads to our spatial variations in stress drop. Additionally, we observe lower stress drops following the MW 6.0 mainshock, consistent with increased damage and decreased fault strength after a large earthquake.},
	keywords = {earthquake stress drop, earthquake swarms, fault zone damage, oceanic transform faults, rupture dynamics, seismic coupling},
	issn = {2169-9356},
	doi = {10.1029/2018JB015942},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JB015942},
	author = {Moyer, Pamela A. and Boettcher, Margaret S. and McGuire, Jeffery J. and Collins, John A.}
}
@article {Zietlow2018,
	title = {Teleseismic S-wave tomography of South Island, New Zealand upper mantle},
	journal = {Geosphere},
	volume = {14},
	number = {3},
	year = {2018},
	month = {jun},
	pages = {1343{\textendash}1364},
	issn = {1553-040X},
	doi = {10.1130/GES01591.1},
	url = {https://pubs.geoscienceworld.org/gsa/geosphere/article/14/3/1343/530581/Teleseismic-Swave-tomography-of-South-Island-New},
	author = {Zietlow, Daniel W. and Sheehan, Anne F. and Bernardino, Melissa V.}
}
@article {Kim2018a,
	title = {Upper crustal Vp / Vs ratios at the Endeavour segment, Juan de Fuca Ridge, from joint inversion of P and S travel times: Implications for hydrothermal circulation},
	journal = {Geochemistry, Geophysics, Geosystems},
	year = {2018},
	month = {dec},
	pages = {2018GC007921},
	issn = {1525-2027},
	doi = {10.1029/2018GC007921},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GC007921},
	author = {Kim, Eunyoung and Toomey, Douglas R. and Hooft, Emilie E. E. and Wilcock, William S. D. and Weekly, Robert T. and Lee, Sang-Mook and Kim, Young Hee}
}
@article {Kim2018,
	title = {Upper crustal Vp / Vs ratios at the Endeavour segment, Juan de Fuca Ridge, from joint inversion of P and S travel times: Implications for hydrothermal circulation},
	journal = {Geochemistry, Geophysics, Geosystems},
	year = {2018},
	month = {dec},
	pages = {2018GC007921},
	issn = {1525-2027},
	doi = {10.1029/2018GC007921},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GC007921},
	author = {Kim, Eunyoung and Toomey, Douglas R. and Hooft, Emilie E. E. and Wilcock, William S. D. and Weekly, Robert T. and Lee, Sang-Mook and Kim, Young Hee}
}
@article {Cai2018,
	title = {Water input into the Mariana subduction zone estimated from ocean-bottom seismic data},
	journal = {Nature},
	volume = {563},
	number = {7731},
	year = {2018},
	month = {nov},
	pages = {389{\textendash}392},
	issn = {0028-0836},
	doi = {10.1038/s41586-018-0655-4},
	url = {http://www.nature.com/articles/s41586-018-0655-4},
	author = {Cai, Chen and Wiens, Douglas A. and Shen, Weisen and Eimer, Melody}
}
@mastersthesis {Tian2017a,
	title = {Ambient Noise Tomography and Microseism Directionalities across the Juan de Fuca Plate},
	year = {2017},
	school = {University of Colorado at Boulder},
	type = {phdPh.D.},
	author = {Tian, Y.}
}
@article {Mousavi2017,
	title = {Automatic noise-removal/signal-removal based on general cross-validation thresholding in synchrosqueezed domain and its application on earthquake data},
	journal = {GEOPHYSICS},
	volume = {82},
	number = {4},
	year = {2017},
	month = {jul},
	pages = {V211{\textendash}V227},
	issn = {0016-8033},
	doi = {10.1190/geo2016-0433.1},
	url = {http://library.seg.org/doi/10.1190/geo2016-0433.1},
	author = {Mousavi, S. Mostafa and Langston, Charles A.}
}
@mastersthesis {Weirathmueller2017b,
	title = {Characteristics of fin whale vocalizations recorded on instruments in the northeast Pacific Ocean},
	year = {2017},
	school = {University of Washington},
	type = {phdPh.D.},
	url = {http://hdl.handle.net/1773/38189},
	author = {Weirathmueller, M. J.}
}
@article {lynner_crustal_2017,
	title = {Crustal structure across the eastern North American margin from ambient noise tomography},
	journal = {Geophysical Research Letters},
	volume = {44},
	number = {13},
	year = {2017},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2017GL073500},
	pages = {6651{\textendash}6657},
	abstract = {Passive tectonic margins, like the eastern North American margin (ENAM), represent the meeting of oceanic and continental material where no active deformation is occurring. The recent ENAM Community Seismic Experiment provides an opportunity to examine the crustal structure across the ENAM owing to the simultaneous deployment of offshore and onshore seismic instrumentation. Using Rayleigh wave phase and group velocities derived from ambient noise data, we invert for shear velocity across the ENAM. We observe a region of transitional crustal thicknesses that connects the oceanic and continental crusts. Associated with the transitional crust is a localized positive gravitational anomaly. Farther east, the East Coast magnetic anomaly (ECMA) is located at the intersection of the transitional and oceanic crusts. We propose that underplating of dense magmatic material along the bottom of the transitional crust is responsible for the gravitational anomaly and that the ECMA demarks the location of initial oceanic crustal formation.},
	keywords = {ambient noise, crustal structure, eastern North American margin, passive margin},
	issn = {1944-8007},
	doi = {10.1002/2017GL073500},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2017GL073500},
	author = {Lynner, Colton and Porritt, Robert W.}
}
@article {Rathnayaka2017,
	title = {Crustal-Scale Seismic Structure From Trench to Forearc in the Cascadia Subduction Zone},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {122},
	number = {9},
	year = {2017},
	month = {sep},
	pages = {7311{\textendash}7328},
	issn = {21699313},
	doi = {10.1002/2017JB014299},
	url = {http://doi.wiley.com/10.1002/2017JB014299},
	author = {Rathnayaka, Sampath and Gao, Haiying}
}
@article {Canales2017a,
	title = {Dry Juan de Fuca slab revealed by quantification of water entering Cascadia subduction zone},
	journal = {Nature Geoscience},
	volume = {10},
	number = {11},
	year = {2017},
	month = {nov},
	pages = {864{\textendash}870},
	issn = {1752-0894},
	doi = {10.1038/ngeo3050},
	url = {http://www.nature.com/articles/ngeo3050},
	author = {Canales, J. P. and Carbotte, S. M. and Nedimovi{\'c}, M. R. and Carton, H.}
}
@article {Cattania2017,
	title = {Dynamic triggering and earthquake swarms on East Pacific Rise transform faults},
	journal = {Geophysical Research Letters},
	volume = {44},
	number = {2},
	year = {2017},
	month = {jan},
	pages = {702{\textendash}710},
	issn = {0094-8276},
	doi = {10.1002/2016GL070857},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2016GL070857},
	author = {Cattania, Camilla and McGuire, Jeffrey J. and Collins, John A.}
}
@article {Weirathmueller2017,
	title = {Estimating range to a vocalizing fin whale using the timing and amplitude of multipath arrivals},
	journal = {The Journal of the Acoustical Society of America},
	volume = {142},
	number = {4},
	year = {2017},
	month = {oct},
	pages = {2101{\textendash}2120},
	issn = {0001-4966},
	doi = {10.1121/1.5005494},
	url = {http://asa.scitation.org/doi/10.1121/1.5005494},
	author = {Weirathmueller, Michelle J. and Wilcock, William S. D. and Hilmo, Rose S.}
}
@article {Sohn2017,
	title = {Exploring the Restless Floor of Yellowstone Lake},
	journal = {Eos},
	year = {2017},
	month = {dec},
	abstract = {Yellowstone Lake, far from any ocean, hosts underwater hot springs similar to those on mid-ocean ridges. A research team is investigating the processes that drive the lake{\textquoteright}s hydrothermal systems.},
	issn = {2324-9250},
	doi = {10.1029/2017EO087035},
	url = {https://eos.org/project-updates/exploring-the-restless-floor-of-yellowstone-lake},
	author = {Sohn, Robert and Harris, Robert and Linder, Chris and Luttrell, Karen and Lovalvo, David and Morgan, Lisa and Seyfried, William and Shanks, Pat}
}
@mastersthesis {Horning2017,
	title = {Geophysical and geochemical constraints on the evolution of oceanic lithosphere from formation to subduction},
	year = {2017},
	school = {Massachusetts Institute of Technology and Woods Hole Oceanographic Institution},
	type = {phdPh.D.},
	address = {Woods Hole, MA},
	doi = {10.1575/1912/8722},
	url = {https://hdl.handle.net/1912/8722},
	author = {Horning, Gregory W.}
}
@article {Wang2017,
	title = {Green{\textquoteright}s Function-Based Tsunami Data Assimilation: A Fast Data Assimilation Approach Toward Tsunami Early Warning},
	journal = {Geophysical Research Letters},
	volume = {44},
	number = {20},
	year = {2017},
	month = {oct},
	pages = {10,282{\textendash}10,289},
	issn = {00948276},
	doi = {10.1002/2017GL075307},
	url = {http://doi.wiley.com/10.1002/2017GL075307},
	author = {Wang, Yuchen and Satake, Kenji and Maeda, Takuto and Gusman, Aditya Riadi}
}
@article {Eilon2017,
	title = {High seismic attenuation at a mid-ocean ridge reveals the distribution of deep melt},
	journal = {Science Advances},
	volume = {3},
	number = {5},
	year = {2017},
	month = {may},
	pages = {e1602829},
	issn = {2375-2548},
	doi = {10.1126/sciadv.1602829},
	url = {https://advances.sciencemag.org/lookup/doi/10.1126/sciadv.1602829},
	author = {Eilon, Zachary C. and Abers, Geoffrey A.}
}
@article {Tian2017,
	title = {Improving ambient noise cross-correlations in the noisy ocean bottom environment of the Juan de Fuca plate},
	journal = {Geophysical Journal International},
	volume = {210},
	number = {3},
	year = {2017},
	month = {sep},
	pages = {1787{\textendash}1805},
	issn = {0956-540X},
	doi = {10.1093/gji/ggx281},
	url = {https://academic.oup.com/gji/article/210/3/1787/3898835},
	author = {Tian, Ye and Ritzwoller, Michael H.}
}
@mastersthesis {Neale2017,
	title = {An investigation into ocean wave sources of ambient seismic noise},
	year = {2017},
	school = {University of Southampton},
	type = {phdPh.D.},
	url = {http://eprints.soton.ac.uk/id/eprint/412555},
	author = {Neale, J. F. W.}
}
@article {lundin_magmatism_2017,
	title = {Magmatism and extension rates at rifted margins},
	journal = {Petroleum Geoscience},
	volume = {24},
	number = {4},
	year = {2017},
	month = {sep},
	pages = {379{\textendash}392},
	abstract = {Rifted margins are commonly classified as either magma-rich or magma-poor. Magma-poor margins are often implicitly related to ultraslow{\textendash}slow extension. Conversely, therefore, magma-rich margins should represent more rapid extension. Although supported by numerical modelling, these relationships are based on limited data and depend on a perhaps spurious comparison between continental margins and spreading ridges. Three case studies from the Atlantic margins are therefore presented here as a local, by no means complete, examination of this concept.Extension rates for magma-poor margins are mainly derived from offshore Iberia, while the best documented rates on magma-rich margins are probably those in the NE Atlantic. Particularly for the NE Atlantic, there is a dependence on the initial oceanic spreading rate as pre-break-up rates are very difficult to quantify. Our two southerly examples, the Central Atlantic and southern South Atlantic, are both magma-rich in parts and have been described as opening during ultraslow{\textendash}slow plate separation. Both would therefore seem to contradict the positive {\textquoteleft}rate-magmatism{\textquoteright} correlation. However, on closer examination, a wide range of initial extension rates are actually possible. This is largely due to poor constraints on break-up ages. The assumption that break-up is synchronous with flood basalt extrusion is flawed, and may have caused initial extension rates to have been significantly underestimated. Additionally, averaging between widely spaced oceanic magnetic anomalies allows for a wide range of extension rates. New, well-constrained ages and event chronologies from critical areas of conjugate margins are needed to determine whether this relationship has global validity.},
	issn = {1354-0793},
	doi = {10.1144/petgeo2016-158},
	url = {https://doi.org/10.1144/petgeo2016-158},
	author = {Lundin, Erik R. and Dor{\'e}, Anthony G. and Redfield, Thomas F.}
}
@article {Byrnes2017a,
	title = {Mantle dynamics beneath the discrete and diffuse plate boundaries of the Juan de Fuca plate: Results from Casascadia Initiative body wave tomography},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {18},
	number = {8},
	year = {2017},
	month = {aug},
	pages = {2906{\textendash}2929},
	issn = {1525-2027},
	doi = {10.1002/2017GC006980},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2017GC006980},
	author = {Byrnes, Joseph S. and Toomey, Douglas R. and Hooft, Emilie E. E. and N{\'a}b{\v e}lek, John and Braunmiller, Jochen}
}
@article {Lynner2017,
	title = {Mantle flow along the eastern North American margin inferred from shear wave splitting},
	journal = {Geology},
	volume = {45},
	number = {10},
	year = {2017},
	month = {oct},
	pages = {867{\textendash}870},
	issn = {0091-7613},
	doi = {10.1130/G38980.1},
	url = {http://pubs.geoscienceworld.org/geology/article/45/10/867/353518/Mantle-flow-along-the-eastern-North-American},
	author = {Lynner, Colton and Bodmer, Miles}
}
@mastersthesis {Byrnes2017,
	title = {Mantle flow and melting beneath young oceanic lithosphere: Seismic studies of the Gal{\'a}pagos Archipelago and the Juan de Fuca Plate},
	year = {2017},
	school = {University of Oregon},
	type = {phdPh.D.},
	url = {http://hdl.handle.net/1794/22638\%09},
	author = {Byrnes, Joseph}
}
@conference {Shi2017,
	title = {Mapping coherent, time-varying wavefronts from the 2011 Tohoku tsunami into enhanced, time-dependent warning messages},
	booktitle = {16th World Conference on Earthquake Engineering},
	year = {2017},
	url = {https://resolver.caltech.edu/CaltechAUTHORS:20170127-163908004},
	author = {Shi, J. and Kohler, M.D. and Sutton, J.N. and Ampuero, J.P.}
}
@article {Agius2017,
	title = {Mapping the mantle transition zone beneath Hawaii from Ps receiver functions: Evidence for a hot plume and cold mantle downwellings},
	journal = {Earth and Planetary Science Letters},
	volume = {474},
	year = {2017},
	month = {sep},
	pages = {226{\textendash}236},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2017.06.033},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X17303497},
	author = {Agius, Matthew R. and Rychert, Catherine A. and Harmon, Nicholas and Laske, Gabi}
}
@article {Flores2017,
	title = {Observations of Seismicity and Ground Motion in the Northeast U.S. Atlantic Margin from Ocean-Bottom Seismometer Data},
	journal = {Seismological Research Letters},
	volume = {88},
	number = {1},
	year = {2017},
	month = {jan},
	pages = {23{\textendash}31},
	issn = {0895-0695},
	doi = {10.1785/0220160079},
	url = {https://pubs.geoscienceworld.org/srl/article/88/1/23-31/314313},
	author = {Flores, Claudia H. and ten Brink, Uri S. and McGuire, Jeffrey J. and Collins, John A.}
}
@article {Doran2017,
	title = {Ocean-Bottom Seismometer Instrument Orientations via Automated Rayleigh-Wave Arrival-Angle Measurements},
	journal = {Bulletin of the Seismological Society of America},
	volume = {107},
	number = {2},
	year = {2017},
	month = {apr},
	pages = {691{\textendash}708},
	issn = {0037-1106},
	doi = {10.1785/0120160165},
	url = {https://pubs.geoscienceworld.org/bssa/article/107/2/691-708/354158},
	author = {Doran, Adrian K. and Laske, Gabi}
}
@article {Yeck2017,
	title = {Offshore Rayleigh group velocity observations of the South Island, New Zealand, from ambient noise data},
	journal = {Geophysical Journal International},
	volume = {209},
	number = {2},
	year = {2017},
	month = {may},
	pages = {827{\textendash}841},
	issn = {0956-540X},
	doi = {10.1093/gji/ggx054},
	url = {https://academic.oup.com/gji/article/209/2/827/2998716},
	author = {Yeck, William L. and Sheehan, Anne F. and Stachnik, Joshua C. and Lin, Fan-Chi}
}
@article {ball_remote_2017,
	title = {Remote detection of cryoacoustic signals using noise interferometry of seafloor pressure data},
	journal = {The Journal of the Acoustical Society of America},
	volume = {141},
	number = {5},
	year = {2017},
	note = {Publisher: Acoustical Society of America},
	month = {may},
	pages = {4047{\textendash}4047},
	issn = {0001-4966},
	doi = {10.1121/1.4989358},
	url = {https://asa.scitation.org/doi/10.1121/1.4989358},
	author = {Ball, Justin S. and Sheehan, Anne F. and Scambos, Ted}
}
@article {Johnson2017,
	title = {Sediment gravity flows triggered by remotely generated earthquake waves},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {122},
	number = {6},
	year = {2017},
	month = {jun},
	pages = {4584{\textendash}4600},
	issn = {21699313},
	doi = {10.1002/2016JB013689},
	url = {http://doi.wiley.com/10.1002/2016JB013689},
	author = {Johnson, H. Paul and Gomberg, Joan S. and Hautala, Susan L. and Salmi, Marie S.}
}
@article {Kawakatsu2017,
	title = {Seismic and Electrical Signatures of the Lithosphere{\textendash}Asthenosphere System of the Normal Oceanic Mantle},
	journal = {Annual Review of Earth and Planetary Sciences},
	volume = {45},
	number = {1},
	year = {2017},
	month = {aug},
	pages = {139{\textendash}167},
	issn = {0084-6597},
	doi = {10.1146/annurev-earth-063016-020319},
	url = {http://www.annualreviews.org/doi/10.1146/annurev-earth-063016-020319},
	author = {Kawakatsu, Hitoshi and Utada, Hisashi}
}
@article {Arnoux2017,
	title = {Seismic evidence that black smoker heat flux is influenced by localized magma replenishment and associated increases in crustal permeability},
	journal = {Geophysical Research Letters},
	volume = {44},
	number = {4},
	year = {2017},
	month = {feb},
	pages = {1687{\textendash}1695},
	issn = {00948276},
	doi = {10.1002/2016GL071990},
	url = {http://doi.wiley.com/10.1002/2016GL071990},
	author = {Arnoux, Gillean M. and Toomey, Douglas R. and Hooft, Emilie E. E. and Wilcock, William S. D. and Morgan, Joanna and Warner, Mike and VanderBeek, Brandon P.}
}
@article {Canales2017,
	title = {Seismic imaging of magma sills beneath an ultramafic-hosted hydrothermal system},
	journal = {Geology},
	volume = {45},
	number = {5},
	year = {2017},
	month = {may},
	pages = {451{\textendash}454},
	issn = {0091-7613},
	doi = {10.1130/G38795.1},
	url = {https://pubs.geoscienceworld.org/geology/article/45/5/451-454/207914},
	author = {Canales, J. Pablo and Dunn, Robert A. and Arai, Ryuta and Sohn, Robert A.}
}
@article {VanderBeek2017,
	title = {Shallow Mantle Anisotropy Beneath the Juan de Fuca Plate},
	journal = {Geophysical Research Letters},
	volume = {44},
	number = {22},
	year = {2017},
	month = {nov},
	pages = {11,382{\textendash}11,389},
	issn = {0094-8276},
	doi = {10.1002/2017GL074769},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2017GL074769},
	author = {VanderBeek, Brandon P. and Toomey, Douglas R.}
}
@article {Wei2017,
	title = {Slab temperature controls on the Tonga double seismic zone and slab mantle dehydration},
	journal = {Science Advances},
	volume = {3},
	number = {1},
	year = {2017},
	month = {jan},
	pages = {e1601755},
	issn = {2375-2548},
	doi = {10.1126/sciadv.1601755},
	url = {https://advances.sciencemag.org/lookup/doi/10.1126/sciadv.1601755},
	author = {Wei, S. Shawn and Wiens, Douglas A. and van Keken, Peter E. and Cai, Chen}
}
@mastersthesis {Sapkota2017,
	title = {Source parameterization of earthquakes along Juan de Fuca transform boundaries},
	year = {2017},
	school = {Oregon State University},
	type = {phdMs.},
	url = {https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/0v838374r},
	author = {Sapkota, B.}
}
@article {Weirathmueller2017a,
	title = {Spatial and temporal trends in fin whale vocalizations recorded in the NE Pacific Ocean between 2003-2013},
	journal = {PLOS ONE},
	volume = {12},
	number = {10},
	year = {2017},
	month = {oct},
	pages = {e0186127},
	issn = {1932-6203},
	doi = {10.1371/journal.pone.0186127},
	url = {https://dx.plos.org/10.1371/journal.pone.0186127},
	author = {Weirathmueller, Michelle J. and Stafford, Kathleen M. and Wilcock, William S. D. and Hilmo, Rose S. and Dziak, Robert P. and Tr{\'e}hu, Anne M.},
	editor = {Li, Songhai}
}
@mastersthesis {Hankins2017,
	title = {A study of the vertical component of ocean floor vibrations in two geographical chokepoints},
	year = {2017},
	school = {Naval Postgraduate School},
	type = {phdMs.},
	url = {https://calhoun.nps.edu/handle/10945/52985},
	author = {Hankins, J.R.}
}
@article {Accardo2017,
	title = {Surface wave imaging of the weakly extended Malawi Rift from ambient-noise and teleseismic Rayleigh waves from onshore and lake-bottom seismometers},
	journal = {Geophysical Journal International},
	volume = {209},
	number = {3},
	year = {2017},
	month = {jun},
	pages = {1892{\textendash}1905},
	issn = {0956-540X},
	doi = {10.1093/gji/ggx133},
	url = {https://academic.oup.com/gji/article/209/3/1892/3098113},
	author = {Accardo, N.J. and Gaherty, J.B. and Shillington, D.J. and Ebinger, C.J. and Nyblade, A.A. and Mbogoni, G.J. and Chindandali, P.R.N. and Ferdinand, R.W. and Mulibo, G.D. and Kamihanda, G. and Keir, D. and Scholz, C. and Selway, K. and O{\textquoteright}Donnell, J.P. and Tepp, G. and Gallacher, R. and Mtelela, K. and Salima, J. and Mruma, A.}
}
@article {An2017,
	title = {Theoretical Solution and Applications of Ocean Bottom Pressure Induced by Seismic Seafloor Motion},
	journal = {Geophysical Research Letters},
	volume = {44},
	number = {20},
	year = {2017},
	month = {oct},
	pages = {10,272{\textendash}10,281},
	issn = {00948276},
	doi = {10.1002/2017GL075137},
	url = {http://doi.wiley.com/10.1002/2017GL075137},
	author = {An, Chao and Cai, Chen and Zheng, Yong and Meng, Lingsen and Liu, Philip}
}
@article {Salmi2017,
	title = {Thermal environment of the Southern Washington region of the Cascadia subduction zone},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {122},
	number = {8},
	year = {2017},
	month = {aug},
	pages = {5852{\textendash}5870},
	issn = {21699313},
	doi = {10.1002/2016JB013839},
	url = {http://doi.wiley.com/10.1002/2016JB013839},
	author = {Salmi, Marie S. and Johnson, H. Paul and Harris, Robert N.}
}
@article {Dunn2017,
	title = {Three-Dimensional Seismic Structure of the Mid-Atlantic Ridge: An Investigation of Tectonic, Magmatic, and Hydrothermal Processes in the Rainbow Area},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {122},
	number = {12},
	year = {2017},
	month = {dec},
	pages = {9580{\textendash}9602},
	issn = {21699313},
	doi = {10.1002/2017JB015051},
	url = {http://doi.wiley.com/10.1002/2017JB015051},
	author = {Dunn, Robert A. and Arai, Ryuta and Eason, Deborah E. and Canales, J. Pablo and Sohn, Robert A.}
}
@article {becel_tsunamigenic_2017,
	title = {Tsunamigenic structures in a creeping section of the Alaska subduction zone},
	journal = {Nature Geoscience},
	volume = {10},
	number = {8},
	year = {2017},
	note = {Publisher: Nature Publishing Group},
	pages = {609{\textendash}613},
	abstract = {Segments of subduction zones that are capable of generating tsunamigenic earthquakes appear to have characteristic structural configurations. These structures include heterogeneous plate interfaces, a small wedge of deformed sediment at the toe of the overriding plate (the frontal prism), and splay faults in the crust of the overriding plate that root within the plate boundary megathrust. Here we use seismic reflection imaging to show that these features also exist within a creeping segment of the Alaska subduction zone, the Shumagin Gap. We identify an active crustal-scale normal fault system that dips landward and resembles that involved in the 2011 Tohoku-oki earthquake in Japan. We also find that the Shumagin Gap has a small frontal prism, a deep-water splay fault, and that the plate interface here is rough and thinly sedimented. We propose that lateral propagation of rupture from a neighbouring segment into the Shumagin Gap may explain a tsunamigenic earthquake that occurred there in 1788 and that tsunamigenic potential should be considered in hazard assessments for the region. Our results demonstrate that structural configurations similar to those in Tohoku may exist in other subduction zones, including within creeping segments or segments with no record of historical megathrust earthquakes, but are under-recognized. Identifying similar configurations globally may improve our ability to anticipate regions capable of generating large tsunamis.},
	keywords = {Geodynamics, Geology, Natural hazards, seismology, Tectonics},
	issn = {1752-0908},
	doi = {10.1038/ngeo2990},
	url = {https://www.nature.com/articles/ngeo2990},
	author = {B{\'e}cel, Anne and Shillington, Donna J. and Delescluse, Matthias and Nedimovi{\'c}, Mladen R. and Abers, Geoffrey A. and Saffer, Demian M. and Webb, Spahr C. and Keranen, Katie M. and Roche, Pierre-Henri and Li, Jiyao and Kuehn, Harold}
}
@article {Horning2016,
	title = {A 2-D tomographic model of the Juan de Fuca plate from accretion at axial seamount to subduction at the Cascadia margin from an active source ocean bottom seismometer survey},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {121},
	number = {8},
	year = {2016},
	month = {aug},
	pages = {5859{\textendash}5879},
	issn = {21699313},
	doi = {10.1002/2016JB013228},
	url = {http://doi.wiley.com/10.1002/2016JB013228},
	author = {Horning, G. and Canales, J. P. and Carbotte, S. M. and Han, S. and Carton, H. and Nedimovi{\'c}, M. R. and van Keken, P. E.}
}
@article {Shillington2016,
	title = {Acquisition of a Unique Onshore/Offshore Geophysical and Geochemical Dataset in the Northern Malawi (Nyasa) Rift},
	journal = {Seismological Research Letters},
	volume = {87},
	number = {6},
	year = {2016},
	month = {nov},
	pages = {1406{\textendash}1416},
	issn = {0895-0695},
	doi = {10.1785/0220160112},
	url = {https://pubs.geoscienceworld.org/srl/article/87/6/1406-1416/314187},
	author = {Shillington, Donna J. and Gaherty, James B. and Ebinger, Cynthia J. and Scholz, Christopher A. and Selway, Kate and Nyblade, Andrew A. and Bedrosian, Paul A. and Class, Cornelia and Nooner, Scott L. and Pritchard, Matthew E. and Elliott, Julie and Chindandali, Patrick R. N. and Mbogoni, Gaby and Ferdinand, Richard Wambura and Boniface, Nelson and Manya, Shukrani and Kamihanda, Godson and Saria, Elifuraha and Mulibo, Gabriel and Salima, Jalf and Mruma, Abdul and Kalindekafe, Leonard and Accardo, Natalie J. and Ntambila, Daud and Kachingwe, Marsella and Mesko, Gary T. and McCartney, Tannis and Maquay, Melania and O{\textquoteright}Donnell, J. P. and Tepp, Gabrielle and Mtelela, Khalfan and Trinhammer, Per and Wood, Douglas and Aaron, Ernest and Gibaud, Mark and Rapa, Martin and Pfeifer, Cathy and Mphepo, Felix and Gondwe, Duncan and Arroyo, Gabriella and Eddy, Celia and Kamoga, Brian and Moshi, Mary}
}
@article {st_clair_along-strike_2016,
	title = {Along-strike structure of the Costa Rican convergent margin from seismic a refraction/reflection survey: Evidence for underplating beneath the inner forearc},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {17},
	number = {2},
	year = {2016},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2015GC006029},
	month = {02/2016},
	pages = {501{\textendash}520},
	abstract = {The convergent margin offshore Costa Rica shows evidence of subsidence due to subduction erosion along the outer forearc and relatively high rates of uplift (\~{}3{\textendash}6 mm/yr) along the coast. Recently erupted arc lavas exhibit a low 10Be signal, suggesting that although nearly the entire package of incoming sediments enters the subduction zone, very little of that material is carried directly with the downgoing Cocos plate to the magma generating depths of the mantle wedge. One mechanism that would explain both the low 10Be and the coastal uplift is the underplating of sediments, tectonically eroded material, and seamounts beneath the inner forearc. We present results of a 320 km long, trench-parallel seismic reflection and refraction study of the Costa Rican forearc. The primary observations are (1) margin perpendicular faulting of the basement, (2) thickening of the Cocos plate to the northwest, and (3) two weak bands of reflections in the multichannel seismic (MCS) reflection image with travel times similar to the top of the subducting Cocos plate. The modeled depths to these reflections are consistent with an \~{}40 km long, 1{\textendash}3 km thick region of underplated material \~{}15 km beneath some of the highest observed coastal uplift rates in Costa Rica.},
	keywords = {convergent margin, Costa Rica, subduction zone processes},
	issn = {1525-2027},
	doi = {10.1002/2015GC006029},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2015GC006029},
	author = {St. Clair, J. and Holbrook, W. S. and Van Avendonk, H. J. A. and Lizarralde, D.}
}
@article {ramsay_anisotropy_2016,
	title = {Anisotropy from SKS splitting across the Pacific-North America plate boundary offshore southern California},
	journal = {Geophysical Journal International},
	volume = {207},
	number = {1},
	year = {2016},
	month = {oct},
	pages = {244{\textendash}258},
	abstract = {SKS arrivals from ocean bottom seismometer (OBS) data from an offshore southern California deployment are analysed for shear wave splitting. The project involved 34 OBSs deployed for 12 months in a region extending up to 500 km west of the coastline into the oceanic Pacific plate. The measurement process consisted of removing the effects of anisotropy using a range of values for splitting fast directions and delay times to minimize energy along the transverse seismometer axis. Computed splitting parameters are unexpectedly similar to onland parameters, exhibiting WSW{\textendash}ENE fast polarization directions and delays between 0.8 and 1.8~s, even for oceanic plate sites. This is the first SKS splitting study to extend across the entire boundary between the North America and Pacific plates, into the oceanic part of the Pacific plate. The splitting results show that the fast direction of anisotropy on the Pacific plate does not align with absolute plate motion (APM), and they extend the trend of anisotropy in southern California an additional 500 km west, well onto the oceanic Pacific plate. We model the finite strain and anisotropy within the asthenosphere associated with density{\textendash}buoyancy driven mantle flow and the effects of APM. In the absence of plate motion effects, such buoyancy driven mantle flow would be NE-directed beneath the Pacific plate observations. The best-fit patterns of mantle flow are inferred from the tomography-based models that show primary influences from foundering higher-density zones associated with the history of subduction beneath North America. The new offshore SKS measurements, when combined with measurements onshore within the plate boundary zone, indicate that dramatic lateral variations in density-driven upper-mantle flow are required from offshore California into the plate boundary zone in California and western Basin and Range.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggw271},
	url = {https://doi.org/10.1093/gji/ggw271},
	author = {Ramsay, Joseph and Kohler, Monica D. and Davis, Paul M. and Wang, Xinguo and Holt, William and Weeraratne, Dayanthie S.}
}
@article {Johnson2016,
	title = {Delayed dynamic triggering: Local seismicity leading up to three remote M >= 6 aftershocks of the 11 April 2012 M8.6 Indian Ocean earthquake},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {121},
	number = {1},
	year = {2016},
	month = {jan},
	pages = {134{\textendash}151},
	issn = {21699313},
	doi = {10.1002/2015JB012243},
	url = {http://doi.wiley.com/10.1002/2015JB012243},
	author = {Johnson, Christopher W. and B{\"u}rgmann, Roland}
}
@article {Sahakian2016,
	title = {Geophysical Evidence for a San Andreas Subparallel Transtensional Fault along the Northeastern Shore of the Salton Sea},
	journal = {Bulletin of the Seismological Society of America},
	volume = {106},
	number = {5},
	year = {2016},
	month = {oct},
	pages = {1963{\textendash}1978},
	issn = {0037-1106},
	doi = {10.1785/0120150350},
	url = {https://pubs.geoscienceworld.org/bssa/article/106/5/1963-1978/350875},
	author = {Sahakian, Valerie and Kell, Annie and Harding, Alistair and Driscoll, Neal and Kent, Graham}
}
@article {webb_high-resolution_2016,
	title = {High-Resolution Seafloor Absolute Pressure Gauge Measurements Using a Better Counting Method},
	journal = {Journal of Atmospheric and Oceanic Technology},
	volume = {33},
	number = {9},
	year = {2016},
	note = {Publisher: American Meteorological Society Section: Journal of Atmospheric and Oceanic Technology},
	month = {sep},
	pages = {1859{\textendash}1874},
	abstract = {Abstract Vibrating quartz force transducers are the critical component of most deep-sea pressure and depth gauges in use in oceanography, producing a frequency output that varies with pressure. Accurate and low drift pressure measurements can be obtained by precisely measuring this frequency. In most implementations, the frequency is determined by counting the number of cycles of a high-frequency standard oscillator occurring during a large number of cycles of the lower-frequency quartz force oscillator. Resolution is limited by the sampling interval (length of counting) and the frequency of the frequency standard. Alternative counting methods can provide significant (20{\textendash}40 dB) improvements in resolution at sampling rates above 1 Hz. Each counting method can be described as a different filter applied to the output of a counter of the frequency standard gated at each transition of the transducer quartz oscillator. Improvements in resolution can be understood as the result of minimizing the aliasing of higher-frequency counting noise into the spectrum below the Nyquist frequency. A simple multipole infinite impulse response (IIR) filter designed to limit spectral leakage of high-frequency noise minimizes the noise spectrum and thereby optimizes the resolution of the pressure output. The resultant noise spectrum rises as frequency squared above 1 Hz, independent of the sampling rate. At frequencies below 1 Hz, it is limited by noise in the electronics driving the force transducer quartz oscillator. Resolution increases with frequency of the frequency standard up to about 200 MHz, plateauing for higher frequencies due to other noise sources (likely electronic).},
	issn = {0739-0572, 1520-0426},
	doi = {10.1175/JTECH-D-15-0114.1},
	url = {https://journals.ametsoc.org/view/journals/atot/33/9/jtech-d-15-0114_1.xml},
	author = {Webb, Spahr C. and Nooner, Scott L.}
}
@article {Lin2016,
	title = {High-resolution seismic constraints on flow dynamics in the oceanic asthenosphere},
	journal = {Nature},
	volume = {535},
	number = {7613},
	year = {2016},
	month = {jul},
	pages = {538{\textendash}541},
	issn = {0028-0836},
	doi = {10.1038/nature18012},
	url = {http://www.nature.com/articles/nature18012},
	author = {Lin, Pei-Ying Patty and Gaherty, James B. and Jin, Ge and Collins, John A. and Lizarralde, Daniel and Evans, Rob. L. and Hirth, Greg}
}
@article {doran_infragravity_2016,
	title = {Infragravity waves and horizontal seafloor compliance},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {121},
	number = {1},
	year = {2016},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2015JB012511},
	pages = {260{\textendash}278},
	abstract = {We report the first consistent observation of horizontal seafloor compliance induced by infragravity (IG) waves. Long-period IG ocean waves manifest themselves as broad, dominant features in ocean bottom pressure and vertical deformation spectra, but signals are rarely (if ever) identified on the horizontal components of traditional ocean bottom seismometers (OBS) due to low signal level and high current-induced tilt noise at long periods. We examine two OBS stations with shallow-buried seismometers: the Monterey Ocean Bottom Broadband site offshore California and the Ocean Seismic Network (OSN) pilot site OSN1B near Hawaii. We use nearby weather buoys to investigate the relationship between the presence of infragravity waves and environmental conditions. We find strong evidence that infragravity wave generation is primarily confined to the near-coastal environment. Additional IG source information is found by examining the directionality of passing IG waves as a function of frequency, which we analyze using the coherence between pressure and the two horizontal components. Finally, we evaluate the implications for a joint vertical and horizontal compliance inversion.},
	keywords = {horizontal infragravity energy, horizontal seafloor compliance},
	issn = {2169-9356},
	doi = {10.1002/2015JB012511},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2015JB012511},
	author = {Doran, Adrian K. and Laske, Gabi}
}
@article {Harris2016,
	title = {Investigations of Shallow Slow Slip Offshore of New Zealand},
	journal = {Eos},
	volume = {97},
	year = {2016},
	month = {mar},
	abstract = {Recent and upcoming studies of the Hikurangi margin east of New Zealand shed light on previously undetectable tectonic movements.},
	issn = {2324-9250},
	doi = {10.1029/2016EO048945},
	url = {https://eos.org/project-updates/investigations-of-shallow-slow-slip-offshore-of-new-zealand},
	author = {Harris, Robert and Wallace, Laura and Webb, Spahr and Ito, Yoshihiro and Mochizuki, Kimihiro and Ichihara, Hiroshi and Henrys, Stuart and Tr{\'e}hu, Anne and Schwartz, Susan and Sheehan, Anne and Saffer, Demian and Lauer, Rachel}
}
@article {Wang2016,
	title = {Invited review paper: Some outstanding issues in the study of great megathrust earthquakes{\textemdash}The Cascadia example},
	journal = {Journal of Geodynamics},
	volume = {98},
	year = {2016},
	month = {aug},
	pages = {1{\textendash}18},
	issn = {02643707},
	doi = {10.1016/j.jog.2016.03.010},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S026437071530017X},
	author = {Wang, Kelin and Tr{\'e}hu, Anne M.}
}
@article {Ball2016,
	title = {Lithospheric shear velocity structure of South Island, New Zealand, from amphibious Rayleigh wave tomography},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {121},
	number = {5},
	year = {2016},
	month = {may},
	pages = {3686{\textendash}3702},
	issn = {21699313},
	doi = {10.1002/2015JB012726},
	url = {http://doi.wiley.com/10.1002/2015JB012726},
	author = {Ball, Justin S. and Sheehan, Anne F. and Stachnik, Joshua C. and Lin, Fan-Chi and Yeck, William L. and Collins, John A.}
}
@article {Chen2016a,
	title = {Measuring earthquake source parameters in the Mendocino triple junction region using a dense OBS array: Implications for fault strength variations},
	journal = {Earth and Planetary Science Letters},
	volume = {453},
	year = {2016},
	month = {nov},
	pages = {276{\textendash}287},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2016.08.022},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X16304459},
	author = {Chen, Xiaowei and McGuire, Jeffrey J.}
}
@article {Trehu2016,
	title = {Measuring slow slip offshore},
	journal = {Science},
	volume = {352},
	number = {6286},
	year = {2016},
	month = {may},
	pages = {654{\textendash}655},
	issn = {0036-8075},
	doi = {10.1126/science.aaf6534},
	url = {https://www.sciencemag.org/lookup/doi/10.1126/science.aaf6534},
	author = {Trehu, A. M.}
}
@article {Chen2016,
	title = {Microseism source direction from noise cross-correlation},
	journal = {Geophysical Journal International},
	volume = {205},
	number = {2},
	year = {2016},
	month = {05/2016},
	pages = {810{\textendash}818},
	abstract = {Inhomogeneous noise sources surrounding stations produce asymmetric amplitudes in cross-correlation functions that yield preferential source directions. Here we show that preprocessing biases the dominant source direction estimate towards the source producing long-duration signals by down-weighting high-amplitude signals. Tests with both synthetic data and observations show that conventional preprocessing, where only earthquakes and local transients (e.g. trawling, fish impacts) are removed, is more sensitive to coherent energy, while one-bit preprocessing and running-absolute-mean preprocessing are more influenced by signal duration. Comparisons between different preprocessing methods are made on data from the Cascadia Initiative ocean bottom seismometer array, where we find that the total energy arriving from pelagic and coastal areas is similar. Moreover, pelagic-generated signals tend to be weaker but have longer duration, in contrast to coastal-generated signals that tend to be stronger but have shorter duration.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggw055},
	url = {https://academic.oup.com/gji/article-lookup/doi/10.1093/gji/ggw055},
	author = {Chen, Zhao and Gerstoft, Peter and Bromirski, Peter D.}
}
@article {Soule2016,
	title = {Near-axis crustal structure and thickness of the Endeavour Segment, Juan de Fuca Ridge},
	journal = {Geophysical Research Letters},
	volume = {43},
	number = {11},
	year = {2016},
	month = {jun},
	pages = {5688{\textendash}5695},
	issn = {00948276},
	doi = {10.1002/2016GL068182},
	url = {http://doi.wiley.com/10.1002/2016GL068182},
	author = {Soule, Dax and Wilcock, William S. D. and Toomey, Douglas R. and Hooft, Emilie E. E. and Weekly, Robert T.}
}
@article {Morgan2016,
	title = {Next-generation seismic experiments {\textendash} II: wide-angle, multi-azimuth, 3-D, full-waveform inversion of sparse field data},
	journal = {Geophysical Journal International},
	volume = {204},
	number = {2},
	year = {2016},
	month = {feb},
	pages = {1342{\textendash}1363},
	issn = {0956-540X},
	doi = {10.1093/gji/ggv513},
	url = {https://academic.oup.com/gji/article-lookup/doi/10.1093/gji/ggv513},
	author = {Morgan, Joanna and Warner, Michael and Arnoux, Gillean and Hooft, Emilie and Toomey, Douglas and VanderBeek, Brandon and Wilcock, William}
}
@article {Peureux2016,
	title = {Ocean bottom pressure records from the Cascadia array and short surface gravity waves},
	journal = {Journal of Geophysical Research: Oceans},
	volume = {121},
	number = {5},
	year = {2016},
	month = {may},
	pages = {2862{\textendash}2873},
	issn = {2169-9275},
	doi = {10.1002/2015JC011580},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2015JC011580},
	author = {Peureux, Charles and Ardhuin, Fabrice}
}
@article {Berger2016,
	title = {An ocean bottom seismic observatory with near real-time telemetry},
	journal = {Earth and Space Science},
	volume = {3},
	number = {2},
	year = {2016},
	month = {feb},
	pages = {68{\textendash}77},
	issn = {2333-5084},
	doi = {10.1002/2015EA000137},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2015EA000137},
	author = {Berger, J. and Laske, G. and Babcock, J. and Orcutt, J.}
}
@article {Bowden2016,
	title = {Offshore Southern California lithospheric velocity structure from noise cross-correlation functions},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {121},
	number = {5},
	year = {2016},
	month = {may},
	pages = {3415{\textendash}3427},
	issn = {21699313},
	doi = {10.1002/2016JB012919},
	url = {http://doi.wiley.com/10.1002/2016JB012919},
	author = {Bowden, D. C. and Kohler, M. D. and Tsai, V. C. and Weeraratne, D. S.}
}
@article {Audet2016,
	title = {Receiver functions using OBS data: promises and limitations from numerical modelling and examples from the Cascadia Initiative},
	journal = {Geophysical Journal International},
	volume = {205},
	number = {3},
	year = {2016},
	month = {jun},
	pages = {1740{\textendash}1755},
	issn = {0956-540X},
	doi = {10.1093/gji/ggw111},
	url = {https://academic.oup.com/gji/article-lookup/doi/10.1093/gji/ggw111},
	author = {Audet, Pascal}
}
@conference {Gardner2016,
	title = {A second look at Chip Scale Atomic Clocks for long term precision timing},
	booktitle = {OCEANS 2016 MTS/IEEE Monterey},
	year = {2016},
	month = {sep},
	pages = {1{\textendash}9},
	publisher = {IEEE},
	organization = {IEEE},
	isbn = {978-1-5090-1537-5},
	doi = {10.1109/OCEANS.2016.7761268},
	url = {http://ieeexplore.ieee.org/document/7761268/},
	author = {Gardner, Alan T. and Collins, John A.}
}
@article {VanderBeek2016,
	title = {Segmentation of mid-ocean ridges attributed to oblique mantle divergence},
	journal = {Nature Geoscience},
	volume = {9},
	number = {8},
	year = {2016},
	month = {aug},
	pages = {636{\textendash}642},
	issn = {1752-0894},
	doi = {10.1038/ngeo2745},
	url = {http://www.nature.com/articles/ngeo2745},
	author = {VanderBeek, Brandon P. and Toomey, Douglas R. and Hooft, Emilie E. E. and Wilcock, William S. D.}
}
@article {Wallace2016,
	title = {Slow slip near the trench at the Hikurangi subduction zone, New Zealand},
	journal = {Science},
	volume = {352},
	number = {6286},
	year = {2016},
	month = {may},
	pages = {701{\textendash}704},
	issn = {0036-8075},
	doi = {10.1126/science.aaf2349},
	url = {https://www.sciencemag.org/lookup/doi/10.1126/science.aaf2349},
	author = {Wallace, L. M. and Webb, S. C. and Ito, Y. and Mochizuki, K. and Hino, R. and Henrys, S. and Schwartz, S. Y. and Sheehan, A. F.}
}
@article {Chakravorty2016,
	title = {Small-scale factors influence mantle flow under the seafloor},
	journal = {Earth Magazine},
	volume = {November},
	year = {2016},
	url = {https://www.earthmagazine.org/article/small-scale-factors-influence-mantle-flow-under-seafloor/},
	author = {Chakravorty, A.}
}
@article {Abers2016,
	title = {Southeast Papuan crustal tectonics: Imaging extension and buoyancy of an active rift},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {121},
	number = {2},
	year = {2016},
	month = {feb},
	pages = {951{\textendash}971},
	issn = {2169-9313},
	doi = {10.1002/2015JB012621},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2015JB012621},
	author = {Abers, G. A. and Eilon, Z. and Gaherty, J. B. and Jin, G. and Kim, YH. and Obrebski, M. and Dieck, C.}
}
@article {Stanley2016,
	title = {Streamlining Rapid Tsunami Forecasting},
	journal = {Eos},
	volume = {97},
	year = {2016},
	month = {may},
	abstract = {With enough sensors, traditional forecasting methods could be replaced by models continuously updated with real-time wave data.},
	issn = {2324-9250},
	doi = {10.1029/2016EO052675},
	url = {https://eos.org/research-spotlights/streamlining-rapid-tsunami-forecasting},
	author = {Stanley, Sarah}
}
@article {Zietlow2016,
	title = {Teleseismic P wave tomography of South Island, New Zealand upper mantle: Evidence of subduction of Pacific lithosphere since 45 Ma},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {121},
	number = {6},
	year = {2016},
	month = {jun},
	pages = {4427{\textendash}4445},
	issn = {21699313},
	doi = {10.1002/2015JB012624},
	url = {http://doi.wiley.com/10.1002/2015JB012624},
	author = {Zietlow, Daniel W. and Molnar, Peter H. and Sheehan, Anne F.}
}
@article {Hawley2016,
	title = {Tomography reveals buoyant asthenosphere accumulating beneath the Juan de Fuca plate},
	journal = {Science},
	volume = {353},
	number = {6306},
	year = {2016},
	month = {sep},
	pages = {1406{\textendash}1408},
	issn = {0036-8075},
	doi = {10.1126/science.aad8104},
	url = {https://www.sciencemag.org/lookup/doi/10.1126/science.aad8104},
	author = {Hawley, W. B. and Allen, R. M. and Richards, M. A.}
}
@article {Gusman2016,
	title = {Tsunami data assimilation of Cascadia seafloor pressure gauge records from the 2012 Haida Gwaii earthquake},
	journal = {Geophysical Research Letters},
	volume = {43},
	number = {9},
	year = {2016},
	month = {may},
	pages = {4189{\textendash}4196},
	issn = {00948276},
	doi = {10.1002/2016GL068368},
	url = {http://doi.wiley.com/10.1002/2016GL068368},
	author = {Gusman, Aditya Riadi and Sheehan, Anne F. and Satake, Kenji and Heidarzadeh, Mohammad and Mulia, Iyan Eka and Maeda, Takuto}
}
@article {Wendel2016,
	title = {Undersea Data Tie Slow Fault Slip to Tsunami-Causing Quakes},
	journal = {Eos},
	volume = {97},
	year = {2016},
	month = {may},
	abstract = {Slow events might help scientists better understand when and why tsunami-generating earthquakes occur.},
	issn = {2324-9250},
	doi = {10.1029/2016EO051993},
	url = {https://eos.org/articles/undersea-data-tie-slow-fault-slip-to-tsunami-causing-quakes},
	author = {Wendel, JoAnna}
}
@article {Wei2016,
	title = {Upper mantle structure of the Tonga-Lau-Fiji region from Rayleigh wave tomography},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {17},
	number = {11},
	year = {2016},
	month = {nov},
	pages = {4705{\textendash}4724},
	issn = {15252027},
	doi = {10.1002/2016GC006656},
	url = {http://doi.wiley.com/10.1002/2016GC006656},
	author = {Wei, S. Shawn and Zha, Yang and Shen, Weisen and Wiens, Douglas A. and Conder, James A. and Webb, Spahr C.}
}
@article {Lin2015,
	title = {The 11 March 2011 Tohoku tsunami wavefront mapping across offshore Southern California},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {120},
	number = {5},
	year = {2015},
	month = {may},
	pages = {3350{\textendash}3362},
	issn = {21699313},
	doi = {10.1002/2014JB011524},
	url = {http://doi.wiley.com/10.1002/2014JB011524},
	author = {Lin, Fan-Chi and Kohler, Monica D. and Lynett, Patrick and Ayca, Aykut and Weeraratne, Dayanthie S.}
}
@article {Sheehan2015,
	title = {Array Observations of the 2012 Haida Gwaii Tsunami Using Cascadia Initiative Absolute and Differential Seafloor Pressure Gauges},
	journal = {Seismological Research Letters},
	volume = {86},
	number = {5},
	year = {2015},
	month = {sep},
	pages = {1278{\textendash}1286},
	issn = {0895-0695},
	doi = {10.1785/0220150108},
	url = {https://pubs.geoscienceworld.org/srl/article/86/5/1278-1286/315554},
	author = {Sheehan, Anne F. and Gusman, Aditya Riadi and Heidarzadeh, Mohammad and Satake, Kenji}
}
@article {Tian2015,
	title = {Directionality of ambient noise on the Juan de Fuca plate: implications for source locations of the primary and secondary microseisms},
	journal = {Geophysical Journal International},
	volume = {201},
	number = {1},
	year = {2015},
	month = {apr},
	pages = {429{\textendash}443},
	issn = {1365-246X},
	doi = {10.1093/gji/ggv024},
	url = {http://academic.oup.com/gji/article/201/1/429/734400/Directionality-of-ambient-noise-on-the-Juan-de},
	author = {Tian, Ye and Ritzwoller, Michael H.}
}
@article {Thomas2015,
	title = {D" observations in the Pacific from PLUME ocean bottom seismometer recordings},
	journal = {Geophysical Journal International},
	volume = {200},
	number = {2},
	year = {2015},
	month = {feb},
	pages = {851{\textendash}862},
	issn = {1365-246X},
	doi = {10.1093/gji/ggu441},
	url = {http://academic.oup.com/gji/article/200/2/851/610697/D-observations-in-the-Pacific-from-PLUME-ocean},
	author = {Thomas, Christine and Laske, Gabi}
}
@article {Janiszewski2015,
	title = {Imaging the Plate Interface in the Cascadia Seismogenic Zone: New Constraints from Offshore Receiver Functions},
	journal = {Seismological Research Letters},
	volume = {86},
	number = {5},
	year = {2015},
	month = {sep},
	pages = {1261{\textendash}1269},
	issn = {0895-0695},
	doi = {10.1785/0220150104},
	url = {https://pubs.geoscienceworld.org/srl/article/86/5/1261-1269/315535},
	author = {Janiszewski, Helen A. and Abers, Geoffrey A.}
}
@article {shillington_link_2015,
	title = {Link between plate fabric, hydration and subduction zone seismicity in Alaska},
	journal = {Nature Geoscience},
	volume = {8},
	number = {12},
	year = {2015},
	note = {Publisher: Nature Publishing Group},
	pages = {961{\textendash}964},
	abstract = {Subduction carries water into the Earth where it can influence seismicity. Analysis of the structure of the Alaskan subduction zone suggests fluid delivery is influenced by faults in the oceanic plate that formed at the mid-ocean ridge.},
	keywords = {Geodynamics, seismology, Tectonics},
	issn = {1752-0908},
	doi = {10.1038/ngeo2586},
	url = {https://www.nature.com/articles/ngeo2586},
	author = {Shillington, Donna J. and B{\'e}cel, Anne and Nedimovi{\'c}, Mladen R. and Kuehn, Harold and Webb, Spahr C. and Abers, Geoffrey A. and Keranen, Katie M. and Li, Jiyao and Delescluse, Matthias and Mattei-Salicrup, Gabriel A.}
}
@article {Masy2015,
	title = {Lithospheric expression of cenozoic subduction, mesozoic rifting and the Precambrian Shield in Venezuela},
	journal = {Earth and Planetary Science Letters},
	volume = {410},
	year = {2015},
	month = {jan},
	pages = {12{\textendash}24},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2014.08.041},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X14005652},
	author = {Masy, Jeniffer and Niu, Fenglin and Levander, Alan and Schmitz, Michael}
}
@article {Reeves2015,
	title = {Lithospheric structure across the California Continental Borderland from receiver functions},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {16},
	number = {1},
	year = {2015},
	month = {jan},
	pages = {246{\textendash}266},
	issn = {15252027},
	doi = {10.1002/2014GC005617},
	url = {http://doi.wiley.com/10.1002/2014GC005617},
	author = {Reeves, Zachary and Leki{\'c}, Vedran and Schmerr, Nicholas and Kohler, Monica and Weeraratne, Dayanthie}
}
@article {Brodie2015,
	title = {Low frequency baleen whale calls detected on ocean-bottom seismometers in the Lau basin, southwest Pacific Ocean},
	journal = {The Journal of the Acoustical Society of America},
	volume = {137},
	number = {1},
	year = {2015},
	month = {jan},
	pages = {53{\textendash}62},
	issn = {0001-4966},
	doi = {10.1121/1.4904556},
	url = {http://asa.scitation.org/doi/10.1121/1.4904556},
	author = {Brodie, Dana C. and Dunn, Robert A.}
}
@article {Martin-Short2015,
	title = {Mantle flow geometry from ridge to trench beneath the Gorda{\textendash}Juan de Fuca plate system},
	journal = {Nature Geoscience},
	volume = {8},
	number = {12},
	year = {2015},
	month = {dec},
	pages = {965{\textendash}968},
	issn = {1752-0894},
	doi = {10.1038/ngeo2569},
	url = {http://www.nature.com/articles/ngeo2569},
	author = {Martin-Short, Robert and Allen, Richard M. and Bastow, Ian D. and Totten, Eoghan and Richards, Mark A.}
}
@article {Eakin2015,
	title = {New geophysical constraints on a failed subduction initiation: The structure and potential evolution of the Gagua Ridge and Huatung Basin},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {16},
	number = {2},
	year = {2015},
	month = {feb},
	pages = {380{\textendash}400},
	issn = {15252027},
	doi = {10.1002/2014GC005548},
	url = {http://doi.wiley.com/10.1002/2014GC005548},
	author = {Eakin, Daniel H. and McIntosh, Kirk D. and Van Avendonk, H. J. A. and Lavier, Luc}
}
@article {Sumy2015,
	title = {Ocean-Bottom Seismograph Performance during the Cascadia Initiative},
	journal = {Seismological Research Letters},
	volume = {86},
	number = {5},
	year = {2015},
	month = {sep},
	pages = {1238{\textendash}1246},
	issn = {0895-0695},
	doi = {10.1785/0220150110},
	url = {https://pubs.geoscienceworld.org/srl/article/86/5/1238-1246/315519},
	author = {Sumy, Danielle F. and Lodewyk, Jessica A. and Woodward, Robert L. and Evers, Brent}
}
@article {Becel2015,
	title = {Origin of dipping structures in fast-spreading oceanic lower crust offshore Alaska imaged by multichannel seismic data},
	journal = {Earth and Planetary Science Letters},
	volume = {424},
	year = {2015},
	month = {aug},
	pages = {26{\textendash}37},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2015.05.016},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X15003052},
	author = {B{\'e}cel, Anne and Shillington, Donna J. and Nedimovi{\'c}, Mladen R. and Webb, Spahr C. and Kuehn, Harold}
}
@article {Barklage2015,
	title = {P and S velocity tomography of the Mariana subduction system from a combined land-sea seismic deployment},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {16},
	number = {3},
	year = {2015},
	month = {mar},
	pages = {681{\textendash}704},
	issn = {15252027},
	doi = {10.1002/2014GC005627},
	url = {http://doi.wiley.com/10.1002/2014GC005627},
	author = {Barklage, Mitchell and Wiens, Douglas A. and Conder, James A. and Pozgay, Sara and Shiobara, Hajime and Sugioka, Hiroko}
}
@article {Gao2015a,
	title = {Preface to the Focus Section on Cascadia Initiative Preliminary Results},
	journal = {Seismological Research Letters},
	volume = {86},
	number = {5},
	year = {2015},
	month = {sep},
	pages = {1235{\textendash}1237},
	issn = {0895-0695},
	doi = {10.1785/0220150160},
	url = {https://pubs.geoscienceworld.org/srl/article/86/5/1235-1237/315517},
	author = {Gao, Haiying and Schwartz, Susan}
}
@article {Morton2015,
	title = {Preliminary Event Detection of Earthquakes Using the Cascadia Initiative Data},
	journal = {Seismological Research Letters},
	volume = {86},
	number = {5},
	year = {2015},
	month = {sep},
	pages = {1270{\textendash}1277},
	issn = {0895-0695},
	doi = {10.1785/0220150098},
	url = {https://pubs.geoscienceworld.org/srl/article/86/5/1270-1277/315541},
	author = {Morton, Emily A. and Bilek, Susan L.}
}
@article {Gao2015,
	title = {A Preliminary Full-Wave Ambient-Noise Tomography Model Spanning from the Juan de Fuca and Gorda Spreading Centers to the Cascadia Volcanic Arc},
	journal = {Seismological Research Letters},
	volume = {86},
	number = {5},
	year = {2015},
	month = {sep},
	pages = {1253{\textendash}1260},
	issn = {0895-0695},
	doi = {10.1785/0220150103},
	url = {https://pubs.geoscienceworld.org/srl/article/86/5/1253-1260/315528},
	author = {Gao, Haiying and Shen, Yang}
}
@article {Bell2015a,
	title = {Removing Noise from the Vertical Component Records of Ocean-Bottom Seismometers: Results from Year One of the Cascadia Initiative},
	journal = {Bulletin of the Seismological Society of America},
	volume = {105},
	number = {1},
	year = {2015},
	month = {feb},
	pages = {300{\textendash}313},
	issn = {0037-1106},
	doi = {10.1785/0120140054},
	url = {https://pubs.geoscienceworld.org/bssa/article/105/1/300-313/323517},
	author = {Bell, Samuel W. and Forsyth, Donald W. and Ruan, Youyi}
}
@article {Bodmer2015,
	title = {Seismic anisotropy beneath the Juan de Fuca plate system: Evidence for heterogeneous mantle flow},
	journal = {Geology},
	year = {2015},
	month = {nov},
	pages = {G37181.1},
	issn = {0091-7613},
	doi = {10.1130/G37181.1},
	url = {https://pubs.geoscienceworld.org/geology/article/43/12/1095-1098/131775},
	author = {Bodmer, Miles and Toomey, Douglas R. and Hooft, Emilie E. and N{\'a}b{\v e}lek, John and Braunmiller, Jochen}
}
@article {Menke2015,
	title = {Seismic anisotropy indicates ridge-parallel asthenospheric flow beneath the Eastern Lau Spreading Center},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {120},
	number = {2},
	year = {2015},
	month = {feb},
	pages = {976{\textendash}992},
	issn = {2169-9313},
	doi = {10.1002/2014JB011154},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2014JB011154},
	author = {Menke, William and Zha, Yang and Webb, Spahr C. and Blackman, Donna K.}
}
@inbook {Cheng2015,
	title = {Seismic Constraints on a Double-Layered Asymmetric Whole-Mantle Plume Beneath Hawai{\textquoteleft}i},
	year = {2015},
	month = {feb},
	pages = {19{\textendash}34},
	doi = {10.1002/9781118872079.ch2},
	url = {http://doi.wiley.com/10.1002/9781118872079.ch2},
	author = {Cheng, Cheng and Allen, Richard M. and Porritt, Rob W. and Ballmer, Maxim D.}
}
@article {Wei2015,
	title = {Seismic evidence of effects of water on melt transport in the Lau back-arc mantle},
	journal = {Nature},
	volume = {518},
	number = {7539},
	year = {2015},
	month = {feb},
	pages = {395{\textendash}398},
	issn = {0028-0836},
	doi = {10.1038/nature14113},
	url = {http://www.nature.com/articles/nature14113},
	author = {Wei, S. Shawn and Wiens, Douglas A. and Zha, Yang and Plank, Terry and Webb, Spahr C. and Blackman, Donna K. and Dunn, Robert A. and Conder, James A.}
}
@article {Trehu2015,
	title = {Seismicity of the Central Cascadia Continental Margin near 44.5 N: A Decadal View},
	journal = {Seismological Research Letters},
	volume = {86},
	number = {3},
	year = {2015},
	month = {may},
	pages = {819{\textendash}829},
	issn = {0895-0695},
	doi = {10.1785/0220140207},
	url = {https://pubs.geoscienceworld.org/srl/article/86/3/819-829/315628},
	author = {Trehu, A. M. and Braunmiller, J. and Davis, E.}
}
@article {Bell2015,
	title = {Shear Velocity Structure of Abyssal Plain Sediments in Cascadia},
	journal = {Seismological Research Letters},
	volume = {86},
	number = {5},
	year = {2015},
	month = {sep},
	pages = {1247{\textendash}1252},
	issn = {0895-0695},
	doi = {10.1785/0220150101},
	url = {https://pubs.geoscienceworld.org/srl/article/86/5/1247-1252/315523},
	author = {Bell, Samuel W. and Ruan, Youyi and Forsyth, Donald W.}
}
@article {Neale2015,
	title = {Source regions and reflection of infragravity waves offshore of the USA{\textquoteright}s Pacific Northwest},
	journal = {Journal of Geophysical Research: Oceans},
	volume = {120},
	number = {9},
	year = {2015},
	month = {sep},
	pages = {6474{\textendash}6491},
	issn = {2169-9275},
	doi = {10.1002/2015JC010891},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2015JC010891},
	author = {Neale, Jennifer and Harmon, Nicholas and Srokosz, Meric}
}
@article {Karalliyadda2015,
	title = {S-wave splitting in the offshore South Island, New Zealand: Insights into plate-boundary deformation},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {16},
	number = {9},
	year = {2015},
	month = {sep},
	pages = {2829{\textendash}2847},
	issn = {15252027},
	doi = {10.1002/2015GC005882},
	url = {http://doi.wiley.com/10.1002/2015GC005882},
	author = {Karalliyadda, S. C. and Savage, M. K. and Sheehan, A. and Collins, J. and Zietlow, D. and Shelley, A.}
}
@article {Dunn2015,
	title = {Tracking stress and hydrothermal activity along the Eastern Lau Spreading Center using seismic anisotropy},
	journal = {Earth and Planetary Science Letters},
	volume = {410},
	year = {2015},
	month = {jan},
	pages = {105{\textendash}116},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2014.11.027},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X14007195},
	author = {Dunn, Robert A.}
}
@article {vidalesbasurto_attenuation_2014,
	title = {An Attenuation Study of Body Waves in the South-Central Region of the Gulf of California, M{\'e}xico},
	journal = {Bulletin of the Seismological Society of America},
	volume = {104},
	number = {4},
	year = {2014},
	month = {jul},
	pages = {2027{\textendash}2042},
	abstract = {{We studied the seismic attenuation of body waves in the south-central region of the Gulf of California (GoC) with records from the Network of Autonomously Recording Seismographs of Baja California (NARS-Baja), from the Centro de Investigaci{\'o}n Cient{\'\i}fica y de Educaci{\'o}n Superior de Ensenada{\textquoteright}s Broadband Seismological Network of the GoC (RESBAN), and from the ocean-bottom seismographs (OBS) deployed as part of the Sea of Cortez Ocean Bottom Array experiment (SCOOBA). We examine 27 well-located earthquakes reported in Sumy et~al. (2013) that occurred from October 2005 to October 2006 with magnitudes (Mw) between 3.5 and 4.8. We estimated S-wave site effects by calculating horizontal-to-vertical spectral ratios and determined attenuation functions with a nonparametric model by inverting the observed spectral amplitudes of 21 frequencies between 0.13 and 12.59~Hz for the SCOOBA (OBS) stations and 19 frequencies between 0.16 and 7.94~Hz for NARS-Baja and RESBAN stations. We calculated the geometrical spreading and the attenuation (1/Q) factors for two distance intervals (10{\textendash}120 and 120{\textendash}220~km, respectively) for each frequency considered. The estimates of Q obtained with the SCOOBA (OBS) records for the interval 10{\textendash}120~km indicate that the P waves attenuate more than S waves (QP=34{\textpm}1.2f 0.82{\textpm}0.10},
	issn = {0037-1106},
	doi = {10.1785/0120140015},
	url = {https://doi.org/10.1785/0120140015},
	author = {Vidales-Basurto, Claudia A. and Castro, Ra{\'u}l R. and Huerta, Carlos I. and Sumy, Danielle F. and Gaherty, James B. and Collins, John A.}
}
@article {toomey_cascadia_2014,
	title = {THE CASCADIA INITIATIVE: A Sea Change In Seismological Studies of Subduction Zones},
	journal = {Oceanography},
	volume = {27},
	number = {2},
	year = {2014},
	note = {Publisher: Oceanography Society},
	pages = {138{\textendash}150},
	abstract = {ABSTRACTIncreasing public awareness that the Cascadia subduction zone in the Pacific Northwest is capable of great earthquakes (magnitude 9 and greater) motivates the Cascadia Initiative, an ambitious onshore/offshore seismic and geodetic experiment that takes advantage of an amphibious array to study questions ranging from megathrust earthquakes, to volcanic arc structure, to the formation, deformation and hydration of the Juan De Fuca and Gorda Plates. Here, we provide an overview of the Cascadia Initiative, including its primary science objectives, its experimental design and implementation, and a preview of how the resulting data are being used by a diverse and growing scientific community. The Cascadia Initiative also exemplifies how new technology and community-based experiments are opening up frontiers for marine science. The new technology{\textemdash}shielded ocean bottom seismometers{\textemdash}is allowing more routine investigation of the source zone of megathrust earthquakes, which almost exclusively lies offshore and in shallow water. The Cascadia Initiative offers opportunities and accompanying challenges to a rapidly expanding community of those who use ocean bottom seismic data.},
	issn = {1042-8275},
	doi = {10.5670/oceanog.2014.49},
	url = {https://www.jstor.org/stable/24862164},
	author = {Toomey, Douglas R. and Allen, Richard M. and Barclay, Andrew H. and Bell, Samuel W. and Bromirski, Peter D. and Carlson, Richard L. and Chen, Xiaowei and Collins, John A. and Dziak, Robert P. and Evers, Brent and Forsyth, Donald W. and Gerstoft, Peter and Hooft, Emilie E.E. and Livelybrooks, Dean and Lodewyk, Jessica A. and Luther, Douglas S. and McGuire, Jeffrey J. and Schwartz, Susan Y. and Tolstoy, Maya and Tr{\'e}hu, Anne M. and Weirathmueller, Michelle and Wilcock, William S.D.}
}
@article {gouedard_correction_2014,
	title = {Correction of Ocean-Bottom Seismometer Instrumental Clock Errors Using Ambient Seismic Noise},
	journal = {Bulletin of the Seismological Society of America},
	volume = {104},
	number = {3},
	year = {2014},
	month = {apr},
	pages = {1276{\textendash}1288},
	abstract = {Very accurate timing of seismic recordings is critical for modern processing techniques. Clock synchronization among the instruments constituting an array is, however, difficult without direct communication between them. Synchronization to Global Positioning System (GPS) time is one option for on-land deployments, but not for underwater surveys as electromagnetic signals do not propagate efficiently in water. If clock drift is linear, time corrections for ocean-bottom seismometer (OBS) deployments can be estimated through GPS synchronization before and after the deployment, but this is not sufficient for many applications as the nonlinear component of the drift can reach tens to hundreds of milliseconds for long-duration experiments. We present two techniques to retrieve timing differences between simultaneous recordings at ocean-bottom instruments after deployment has ended. Both techniques are based on the analysis of the cross correlation of ambient seismic noise and are effective even if clock drift is nonlinear. The first, called time symmetry analysis, is easy to apply but requires a proper illumination so that the noise cross-correlation functions are symmetric in time. The second is based on the doublet analysis method and does not have this restriction. Advantages and drawbacks of both approaches are discussed. Application to two OBS data sets shows that both can achieve synchronization of recordings down to about five milliseconds (a few percent of the main period used).},
	issn = {0037-1106},
	doi = {10.1785/0120130157},
	url = {https://doi.org/10.1785/0120130157},
	author = {Gou{\'e}dard, Pierre and Seher, Tim and McGuire, Jeffrey J. and Collins, John A. and van der Hilst, Robert D.}
}
@article {eakin_crustal-scale_2014,
	title = {Crustal-scale seismic profiles across the Manila subduction zone: The transition from intraoceanic subduction to incipient collision},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {119},
	number = {1},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2013JB010395},
	pages = {1{\textendash}17},
	abstract = {AbstractWe use offshore multichannel seismic (MCS) reflection and wide-angle seismic data sets to model the velocity structure of the incipient arc-continent collision along two trench perpendicular transects in the Bashi Strait between Taiwan and Luzon. This area represents a transition from a tectonic regime dominated by subduction of oceanic crust of the South China Sea, west of the Philippines, to one dominated by subduction and eventual collision of rifted Chinese continental crust with the Luzon volcanic arc culminating in the Taiwan orogeny. The new seismic velocity models show evidence for extended to hyperextended continental crust, 10{\textendash}15 km thick, subducting along the Manila trench at 20.5{\textdegree}N along transect T1, as well as evidence indicating that this thinned continental crust is being structurally underplated to the accretionary prism at 21.5{\textdegree}N along transect T2, but not along T1 to the south. Coincident MCS reflection imaging shows highly stretched and faulted crust west of the trench along both transects and what appears to be a midcrustal detachment along transect T2, a potential zone of weakness that may be exploited by accretionary processes during subduction. An additional seismic reflection transect south of T1 shows subduction of normal ocean crust at the Manila trench.},
	keywords = {accretion, collision, rifted margin, subduction, Taiwan},
	issn = {2169-9356},
	doi = {10.1002/2013JB010395},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2013JB010395},
	author = {Eakin, Daniel H. and McIntosh, Kirk D. and Van Avendonk, H. J. A. and Lavier, Luc and Lester, Ryan and Liu, Char-Shine and Lee, Chao-Shing}
}
@article {van_avendonk_deep_2014,
	title = {Deep crustal structure of an arc-continent collision: Constraints from seismic traveltimes in central Taiwan and the Philippine Sea},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {119},
	number = {11},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2014JB011327},
	pages = {8397{\textendash}8416},
	abstract = {The collision of continental crust of the Eurasian Plate with the overriding Luzon Arc in central Taiwan has led to compression, uplift, and exhumation of rocks that were originally part of the Chinese rifted margin. Though the kinematics of the fold-thrust belt on the west side of the orogen has been described in detail, the style of deformation in the lower crust beneath Taiwan is still not well understood. In addition, the fate of the Luzon Arc and Forearc in the collision is also not clear. Compressional wave arrival times from active-source and earthquake seismic data from the Taiwan Integrated Geodynamic Research program constrain the seismic velocity structure of the lithosphere along transect T5, an east-west corridor in central Taiwan. The results of our analysis indicate that the continental crust of the Eurasian margin forms a broad crustal root beneath central Taiwan, possibly with a thickness of 55 km. Compressional seismic velocities beneath the Central Range of Taiwan are as low as 5.5 km/s at 25 km depth, whereas P wave seismic velocities in the middle crust on the eastern flank of the Taiwan mountain belt average 6.5{\textendash}7.0 km/s. This suggests that the incoming sediments and upper crust of the Eurasian Plate are buried to midcrustal depth in the western flank of the orogen before they are exhumed in the Central Range. To the east, the Luzon Arc and Forearc are deformed beneath the Coastal Range of central Taiwan. Fragments of the rifted margin of the South China Sea that were accreted in the early stages of the collision form a new backstop that controls the exhumation of Eurasian strata to the west in this evolving mountain belt.},
	keywords = {arc-continent collision, earthquakes, Philippine Sea Plate, seismic refraction, Taiwan, tomography},
	issn = {2169-9356},
	doi = {10.1002/2014JB011327},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2014JB011327},
	author = {Van Avendonk, H. J. A. and Kuo-Chen, H. and McIntosh, K. D. and Lavier, L. L. and Okaya, D. A. and Wu, F. T. and Wang, C. Y. and Lee, C. S. and Liu, C. S.}
}
@article {takeo_estimation_2014,
	title = {Estimation of azimuthal anisotropy in the NW Pacific from seismic ambient noise in seafloor records},
	journal = {Geophysical Journal International},
	volume = {199},
	number = {1},
	year = {2014},
	pages = {11{\textendash}22},
	abstract = {We analysed background surface waves in seismic ambient noise by cross-correlating continuous records of eight ocean bottom seismometers and nine differential pressure gauges deployed in the northwestern Pacific Ocean by the PLATE project. After estimating the clock delay and instrumental phase responses of differential pressure gauges by using cross-correlation functions, we measured average phase velocities in the area of the array for the fundamental-, first higher- and second higher-mode Rayleigh waves, and the fundamental-mode Love waves at a period range of 3{\textendash}40 s by waveform fitting. We then measured phase-velocity anomalies of fundamental-mode and first higher-mode Rayleigh waves for each pair of stations at a period range of 5{\textendash}25 s, and corrected the effect of variation in water-depths. The seismic anomalies imply the presence of strong azimuthal anisotropy beneath the eastern part of array. The direction of maximum velocity is approximately N35{\textdegree}E in the fossil seafloor spreading direction perpendicular to magnetic lineations from the ancient triple junction at this location. The peak-to-peak intensity of shear-wave velocity anisotropy in the mantle is~\~{}7~per cent.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggu240},
	url = {https://doi.org/10.1093/gji/ggu240},
	author = {Takeo, Akiko and Forsyth, Donald W. and Weeraratne, Dayanthie S. and Nishida, Kiwamu}
}
@article {jones_global_2014,
	title = {Global seismic network takes to the seas},
	journal = {Nature},
	volume = {507},
	number = {7491},
	year = {2014},
	note = {Number: 7491 Publisher: Nature Publishing Group},
	month = {mar},
	pages = {151{\textendash}151},
	abstract = {Two systems could plug the ocean-sized gap in earthquake detection.},
	keywords = {Geophysics, Ocean sciences},
	issn = {1476-4687},
	doi = {10.1038/507151a},
	url = {https://www.nature.com/articles/507151a},
	author = {Jones, Nicola}
}
@article {froment_imaging_2014,
	title = {Imaging along-strike variations in mechanical properties of the Gofar transform fault, East Pacific Rise},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {119},
	number = {9},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2014JB011270},
	pages = {7175{\textendash}7194},
	abstract = {AbstractA large part of global plate motion on mid-ocean ridge transform faults (RTFs) is not accommodated as major earthquakes. When large earthquakes do occur, they often repeat quasiperiodically. We focus here on the high slip rate (\~{}14 cm/yr) Gofar transform fault on the equatorial East Pacific Rise. This fault is subdivided into patches that slip during Mw 5.5{\textendash}6 earthquakes every 5 to 6 years. These patches are separated by rupture barriers that accommodate slip through swarms of smaller events and/or aseismic creep. We performed an imaging study to investigate which spatiotemporal variations of the fault zone properties control this segmentation in mechanical behavior and could explain the specific behavior of RTFs at the global scale. We adopt a double-difference approach in a joint inversion of active air gun shots and microseismicity recorded for 1 year. This data set includes the 2008 Mw 6 Gofar earthquake. The along-strike P wave velocity structure reveals an abrupt transition between the barrier area, characterized by a damaged fault zone of 10{\textendash}20\% reduced Vp and a nearly intact fault zone in the asperity area. The importance of the strength of the damage zone on the mechanical behavior is supported by the temporal S wave velocity changes which suggest increased damage within the barrier area, during the week preceding the Mw 6 earthquake. Our results support the conclusion that extended highly damaged zones are the key factor in limiting the role of major earthquakes to accommodate plate motion along RTFs.},
	keywords = {double-difference tomography, fault zone, imaging, mid-ocean ridge transform fault},
	issn = {2169-9356},
	doi = {10.1002/2014JB011270},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2014JB011270},
	author = {Froment, B. and McGuire, J. J. and van der Hilst, R. D. and Gou{\'e}dard, P. and Roland, E. C. and Zhang, H. and Collins, J. A.}
}
@article {godin_interferometry_2014,
	title = {Interferometry of infragravity waves off New Zealand},
	journal = {Journal of Geophysical Research: Oceans},
	volume = {119},
	number = {2},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2013JC009395},
	pages = {1103{\textendash}1122},
	abstract = {AbstractWave interferometry is a remote sensing technique, which is increasingly employed in helioseismology, seismology, and acoustics to retrieve parameters of the propagation medium from two-point cross-correlation functions of random wavefields. Here we apply interferometry to yearlong records of seafloor pressure at 28 locations off New Zealand{\textquoteright}s South Island to investigate propagation and directivity properties of infragravity waves away from shore. A compressed cross-correlation function technique is proposed to make the interferometry of dispersive waves more robust, decrease the necessary noise averaging time, and simplify retrieval of quantitative information from noise cross correlations. The emergence of deterministic wave arrivals from cross correlations of random wavefields is observed up to the maximum range of 692 km between the pressure sensors in the array. Free, linear waves with a strongly anisotropic distribution of power flux density are found to be dominant in the infragravity wavefield. Lowest-frequency components of the infragravity wavefield are largely isotropic. The anisotropy has its maximum in the middle of the spectral band and decreases at the high-frequency end of the spectrum. Highest anisotropy peaks correspond to waves coming from portions of the New Zealand{\textquoteright}s shoreline. Significant contributions are also observed from waves propagating along the coastline and probably coming from powerful sources in the northeast Pacific. Infragravity wave directivity is markedly different to the east and to the west of the South Island. The northwest coast of the South Island is found to be a net source of the infragravity wave energy.},
	keywords = {deep ocean, random wave fields, Surface gravity waves, wave interferometry},
	issn = {2169-9291},
	doi = {10.1002/2013JC009395},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2013JC009395},
	author = {Godin, Oleg A. and Zabotin, Nikolay A. and Sheehan, Anne F. and Collins, John A.}
}
@article {ball_joint_2014,
	title = {A joint Monte Carlo analysis of seafloor compliance, Rayleigh wave dispersion and receiver functions at ocean bottom seismic stations offshore New Zealand},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {15},
	number = {12},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2014GC005412},
	pages = {5051{\textendash}5068},
	abstract = {Teleseismic body-wave imaging techniques such as receiver function analysis can be notoriously difficult to employ on ocean-bottom seismic data due largely to multiple reverberations within the water and low-velocity sediments. In lieu of suppressing this coherently scattered noise in ocean-bottom receiver functions, these site effects can be modeled in conjunction with shear velocity information from seafloor compliance and surface wave dispersion measurements to discern crustal structure. A novel technique to estimate 1-D crustal shear-velocity profiles from these data using Monte Carlo sampling is presented here. We find that seafloor compliance inversions and P-S conversions observed in the receiver functions provide complimentary constraints on sediment velocity and thickness. Incoherent noise in receiver functions from the MOANA ocean bottom seismic experiment limit the accuracy of the practical analysis at crustal scales, but synthetic recovery tests and comparison with independent unconstrained nonlinear optimization results affirm the utility of this technique in principle.},
	keywords = {Monte Carlo, New Zealand, OBS receiver function, seafloor compliance, sediment shear modes, surface waves},
	issn = {1525-2027},
	doi = {10.1002/2014GC005412},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2014GC005412},
	author = {Ball, Justin S. and Sheehan, Anne F. and Stachnik, Joshua C. and Lin, Fan-Chi and Collins, John A.}
}
@article {ruan_marine_2014,
	title = {Marine sediment shear velocity structure from the ratio of displacement to pressure of Rayleigh waves at seafloor},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {119},
	number = {8},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2014JB011162},
	pages = {6357{\textendash}6371},
	abstract = {AbstractThe complex ratio of vertical displacement to pressure (D/P) at seafloor is a function of frequency. It is sensitive to the subsurface elastic properties, particularly the shear modulus, and therefore can be used to determine the shear velocity and thickness of marine sediments. Instead of using compliance in response to loading of long-period infragravity waves as in previous studies, we investigate the transfer function from pressure to displacement using Rayleigh waves generated by microseisms and earthquakes. We find that at frequencies between 0.1 and 0.2 Hz, the Rayleigh wave transfer function is very sensitive to marine sediments and can be reliably obtained from microseism noise. Using a surface wave mode method, we calculate synthetic D/P ratios and examine their sensitivity to water depth, shear wave speed, and thickness of sediments. We develop a method to invert the Rayleigh wave D/P ratio for a regional 1-D profile of sediment shear wave speed and associated sediment thickness beneath each ocean bottom seismograph (OBS). We apply our method to a group of deep water OBSs deployed in the Cascadia Initiative and obtain a well-resolved depth-dependent shear wave speed for sediments on the Juan de Fuca plate and shear wave traveltime delays caused by sediments at each station.},
	keywords = {admittance, D/P ratio method, marine sediment, microseism noise, Rayleigh waves, shear wave speed},
	issn = {2169-9356},
	doi = {10.1002/2014JB011162},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2014JB011162},
	author = {Ruan, Youyi and Forsyth, Donald W. and Bell, Samuel W.}
}
@article {collins_pn_2014,
	title = {Pn anisotropy beneath the South Island of New Zealand and implications for distributed deformation in continental lithosphere},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {119},
	number = {10},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2014JB011233},
	pages = {7745{\textendash}7767},
	abstract = {Pn travel times from regional earthquakes recorded both by stations on New Zealand and by ocean bottom seismographs deployed offshore indicate anisotropy in the uppermost mantle beneath the region. The largest anisotropy of 8\% ({\textpm}2\%, 1σ) lies beneath the deforming part of the South Island to just off its West Coast, a zone roughly 100{\textendash}200 km wide. The fastest propagation is aligned N60{\textdegree}E ({\textpm}3{\textdegree}), essentially parallel to the largely strike-slip relative plate motion since 20 Ma, also N60{\textdegree}E. The magnitude of anisotropy decreases abruptly northwest and southeast of this zone, and on the southeast side of the island, the orientation of fastest propagation is between N32{\textdegree}W and N-S. The N60{\textdegree}E orientation of fast propagation is consistent with finite strain within the uppermost part of the mantle lithosphere if the measured 850 km of displacement of the Pacific plate past the Australia plate is spread over a region with a width of 100{\textendash}200 km. The agreement of this orientation of fast propagation with the orientation or relative plate motion suggests the possibility of but does not require some dynamic recrystallization in rock as cold as 500{\textendash}800{\textdegree}C, where Peierls creep seems to be the likely deformation mechanism. Such a strain distribution matches deformation of a thin viscous sheet that obeys a constitutive relationship of the form , where is the average strain rate and τ is the operative deviatoric stress, with an average value of n ≈ 3{\textendash}10. Presumably, the NW-SE fast propagation in the region southeast of the island results from strain that precedes the Cenozoic deformation that has shaped the island.},
	keywords = {anisotropy, Lithosphere, New Zealand, Pn},
	issn = {2169-9356},
	doi = {10.1002/2014JB011233},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2014JB011233},
	author = {Collins, John A. and Molnar, Peter}
}
@article {shintaku_pn_2014,
	title = {Pn anisotropy in Mesozoic western Pacific lithosphere},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {119},
	number = {4},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2013JB010534},
	pages = {3050{\textendash}3063},
	abstract = {Pn is the high-frequency, scattered P phase guided for great distances within the old oceanic lithosphere. Two arrays of ocean bottom seismometers were deployed on old (150{\textendash}160 Ma) seafloor in the northwestern Pacific south of Shatsky Rise for the Pacific Lithosphere Anisotropy and Thickness Experiment. We use Pn phases from 403 earthquakes during the 1 year of deployment to measure apparent velocities across the arrays. Each array was deployed on a separate limb of a magnetic bight, formed near a fast-spreading, ridge-ridge-ridge triple junction. Using high-frequency waves (5{\textendash}10 Hz), we look at variations of Pn velocities as a function of azimuth. In the western array, we find Pn anisotropy with velocities ranging from 8.7 km/s in the back azimuth (θ) direction of 310{\textdegree} to 7.7 km/s at 350{\textdegree}. In the eastern array, the velocity ranges from 8.5 km/s in back azimuth direction of 210{\textdegree} to 7.7 km/s at 260{\textdegree} and 310{\textdegree}. We observe rapid velocity changes with azimuth in the both arrays requiring sinusoidal variations of roughly equal amplitude as a function of both 2θ and 4θ, which is not expected for the orthorhombic symmetry of olivine or orthopyroxene. The fastest directions on the two limbs are roughly orthogonal to each other suggesting the dominance of fossil anisotropy, but the fast directions of the 2θ components are skewed counterclockwise from the spreading directions. We speculate that the rapid azimuthal variations may be caused by vertical stratification with changing anisotropy with depth in the oceanic lithosphere.},
	keywords = {anisotropy, asthenosphere, mantle, oceanic lithosphere, Pn waves, western Pacific},
	issn = {2169-9356},
	doi = {10.1002/2013JB010534},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2013JB010534},
	author = {Shintaku, Natsumi and Forsyth, Donald W. and Hajewski, Christina J. and Weeraratne, Dayanthie S.}
}
@article {wolfson-schwehr_relationship_2014,
	title = {The relationship between seismicity and fault structure on the Discovery transform fault, East Pacific Rise},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {15},
	number = {9},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2014GC005445},
	pages = {3698{\textendash}3712},
	abstract = {There is a global seismic moment deficit on mid-ocean ridge transform faults, and the largest earthquakes on these faults do not rupture the full fault area. We explore the influence of physical fault structure, including step-overs in the fault trace, on the seismic behavior of the Discovery transform fault, 4S on the East Pacific Rise. One year of microseismicity recorded during a 2008 ocean bottom seismograph deployment (24,377 0 ML 4.6 earthquakes) and 24 years of Mw 5.4 earthquakes obtained from the Global Centroid Moment Tensor catalog, are correlated with surface fault structure delineated from high-resolution multibeam bathymetry. Each of the 15 5.4 Mw 6.0 earthquakes that occurred on Discovery between 1 January 1990 and 1 April 2014 was relocated into one of five distinct rupture patches using a teleseismic surface wave cross-correlation technique. Microseismicity was relocated using the HypoDD relocation algorithm. The western fault segment of Discovery (DW) is composed of three zones of varying structure and seismic behavior: a zone with no large events and abundant microseismicity, a fully coupled zone with large earthquakes, and a complex zone with multiple fault strands and abundant seismicity. In general, microseismicity is reduced within the patches defined by the large, repeating earthquakes. While the extent of the large rupture patches on DW correlates with physical features in the bathymetry, step-overs in the primary fault trace are not observed at patch boundaries, suggesting along-strike heterogeneity in fault zone properties controls the size and location of the large events.},
	keywords = {earthquakes, East Pacific Rise, fault structure, transform fault},
	issn = {1525-2027},
	doi = {10.1002/2014GC005445},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2014GC005445},
	author = {Wolfson-Schwehr, Monica and Boettcher, Margaret S. and McGuire, Jeffrey J. and Collins, John A.}
}
@article {booth_upper_2014,
	title = {Upper mantle Q structure beneath old seafloor in the western Pacific},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {119},
	number = {4},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2013JB010589},
	pages = {3448{\textendash}3461},
	abstract = {The Pacific Lithosphere Anisotropy and Thickness Experiment ocean bottom seismometer array south of the Shatsky Rise allows imaging the attenuation structure of the upper mantle in the oldest parts of the Pacific Ocean. The array consisted of eight seismometers with a lateral extent of 200 km by 600 km. Intermediate- and deep-focus earthquake sources in the Mariana and Izu-Bonin subduction zones provide paths that probe different depths beneath the seafloor. Acceleration spectra from the vertical component of P waves are inverted for the attenuation operator and corner frequency. Pn propagation indicates very high Qp values in the lithosphere, of order 1000, while path-average Qp values in the upper mantle are on the order of 400. The variety of source epicentral distances and depths enables us to deduce the vertical Qp-1 structure of the upper mantle. Using the amplitude spectra directly in a weighted least squares problem that accounts for the effects of triplications in the traveltime curves, we invert for Qp-1 as a function of depth. We demonstrate that Qp is frequency dependent and adopt a power law dependence with coefficient α = 0.27. We resolve three distinct layers using a reference frequency of 1 Hz with Qp on the order of 145 at depths 100{\textendash}250 km, Qp on the order of 350 at depths 250{\textendash}410 km, and very high Qp with attenuation indistinguishable from zero for depths below 410 km. The P waves have a component of scattering, and thus, Qp-1 represents the maximum intrinsic attenuation beneath normal undisturbed oceanic lithosphere.},
	keywords = {attenuation, Pacific, upper mantle},
	issn = {2169-9356},
	doi = {10.1002/2013JB010589},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2013JB010589},
	author = {Booth, Catherine M. and Forsyth, Donald W. and Weeraratne, Dayanthie S.}
}
@article {zietlow_upper_2014,
	title = {Upper mantle seismic anisotropy at a strike-slip boundary: South Island, New Zealand},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {119},
	number = {2},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2013JB010676},
	pages = {1020{\textendash}1040},
	abstract = {New shear wave splitting measurements made from stations onshore and offshore the South Island of New Zealand show a zone of anisotropy 100{\textendash}200 km wide. Measurements in central South Island and up to approximately 100 km offshore from the west coast yield orientations of the fast quasi-shear wave nearly parallel to relative plate motion, with increased obliquity to this orientation observed farther from shore. On the eastern side of the island, fast orientations rotate counterclockwise to become nearly perpendicular to the orientation of relative plate motion approximately 200 km off the east coast. Uniform delay times between the fast and slow quasi-shear waves of nearly 2.0 s onshore continue to stations approximately 100 km off the west coast, after which they decrease to 1 s at 200 km. Stations more than 300 km from the west coast show little to no splitting. East coast stations have delay times around 1 s. Simple strain fields calculated from a thin viscous sheet model (representing distributed lithospheric deformation) with strain rates decreasing exponentially to both the northwest and southeast with e-folding dimensions of 25{\textendash}35 km (approximately 75\% of the deformation within a zone 100{\textendash}140 km wide) match orientations and amounts of observed splitting. A model of deformation localized in the lithosphere and then spreading out in the asthenosphere also yields predictions consistent with observed splitting if, at depths of 100{\textendash}130 km below the lithosphere, typical grain sizes are 6{\textendash}7 mm.},
	keywords = {mantle lithosphere, MOANA, New Zealand, ocean bottom seismometers, seismic anisotropy, South Island},
	issn = {2169-9356},
	doi = {10.1002/2013JB010676},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2013JB010676},
	author = {Zietlow, Daniel W. and Sheehan, Anne F. and Molnar, Peter H. and Savage, Martha K. and Hirth, Greg and Collins, John A. and Hager, Bradford H.}
}
@article {dunn_crustal_2013,
	title = {Crustal construction and magma chamber properties along the Eastern Lau Spreading Center},
	journal = {Earth and Planetary Science Letters},
	volume = {371-372},
	year = {2013},
	month = {jun},
	pages = {112{\textendash}124},
	abstract = {The L-SCAN active-source seismic tomography experiment maps the crustal structure and magmatic system along a 120-km-long section of the back-arc Eastern Lau Spreading Center (ELSC), where the ridge undergoes abrupt changes in morphology and composition associated with increasing proximity to the Tofua volcanic arc. Using this dataset, we picked \textasciitilde197,000 P-wave travel times from 57 seismic airgun lines recorded at 83 ocean bottom seismograph stations, and inverted for a 3-D P-wave velocity image. The seismic images reveal a prominent, but narrow, seismic low velocity volume (LVV) located beneath all surveyed ridge segments, consistent with the high temperatures and melt of a crustal magmatic system. Crustal magmatic systems thus underlie spreading axes even where previous seismic reflection surveys did not detect magma lens reflectors, accounting for the heat source of high-temperature hydrothermal vents in these areas. The top of the LVV closely follows the ridge axis and steps across three overlapping spreading centers. As the offset of the overlap increases, the LVV becomes increasingly discontinuous across the ridge limbs. Surprisingly, the LVV is as much as twice as wide, but deeper, in the northern part of the ridge system where the crust is thinner, as compared to the LVV beneath the southern segments, where the crust is relatively thicker. The width of the LVV may be modulated by the degree of deep hydrothermal activity or temporal variations in melt supply, and thus may not correlate directly with the average melt flux as indicated by crustal thickness. Over the past 4Myr, the location of the ridge has swept across different mantle compositional domains, and the crust produced at the ridge formed a zoned pattern. The interpretation is that thick, highly porous, volcanic layers with felsic compositions cap regions of thick crust; thinner volcanic layers of basaltic composition cap regions of thinner crust. The zonal pattern indicates that the influence of slab-derived water on crustal construction has substantially decreased over time.},
	keywords = {back-arc basin, Eastern Lau Spreading Center, magma chamber, mantle melting, mid-ocean ridge, seismic tomography},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2013.04.008},
	url = {https://www.sciencedirect.com/science/article/pii/S0012821X13001891},
	author = {Dunn, Robert A. and Martinez, Fernando and Conder, James A.}
}
@article {stephen_deep_2013,
	title = {Deep seafloor arrivals in long range ocean acoustic propagation},
	journal = {The Journal of the Acoustical Society of America},
	volume = {134},
	number = {4},
	year = {2013},
	note = {Publisher: Acoustical Society of America},
	month = {oct},
	pages = {3307{\textendash}3317},
	abstract = {Ocean bottom seismometer observations at 5000 m depth during the long-range ocean acoustic propagation experiment in the North Pacific in 2004 show robust, coherent, late arrivals that are not readily explained by ocean acoustic propagation models. These {\textquotedblleft}deep seafloor{\textquotedblright} arrivals are the largest amplitude arrivals on the vertical particle velocity channel for ranges from 500 to 3200 km. The travel times for six (of 16 observed) deep seafloor arrivals correspond to the sea surface reflection of an out-of-plane diffraction from a seamount that protrudes to about 4100 m depth and is about 18 km from the receivers. This out-of-plane bottom-diffracted surface-reflected energy is observed on the deep vertical line array about 35 dB below the peak amplitude arrivals and was previously misinterpreted as in-plane bottom-reflected surface-reflected energy. The structure of these arrivals from 500 to 3200 km range is remarkably robust. The bottom-diffracted surface-reflected mechanism provides a means for acoustic signals and noise from distant sources to appear with significant strength on the deep seafloor.},
	issn = {0001-4966},
	doi = {10.1121/1.4818845},
	url = {https://asa.scitation.org/doi/full/10.1121/1.4818845},
	author = {Stephen, Ralph A. and Thompson Bolmer, S. and Udovydchenkov, Ilya A. and Worcester, Peter F. and Dzieciuch, Matthew A. and Andrew, Rex K. and Mercer, James A. and Colosi, John A. and Howe, Bruce M.}
}
@article {mcintosh_inversion_2013,
	title = {Inversion of a hyper-extended rifted margin in the southern Central Range of Taiwan},
	journal = {Geology},
	volume = {41},
	number = {8},
	year = {2013},
	month = {aug},
	pages = {871{\textendash}874},
	abstract = {Seismic reflection and wide-angle data acquired across, south, and west of Taiwan show that extended to hyper-extended continental crust of the Chinese continental margin is present more than 200 km south of the shelf and is subducting at the Manila Trench. Furthermore, crustal-scale tomographic velocity models show that this crust is underthrusted to \~{}15 km depth below the accretionary prism, where it then is structurally underplated to the base of the prism. We document an increasing volume of accreted crust from south to north, and in our northern transect high-velocity material of the accretionary prism can be directly linked to outcrops of Central Range basement rocks. In map view the Central Range of Taiwan is clearly contiguous with the Hengchun Peninsula and Hengchun submarine ridge to the south. Accordingly, we propose a new model in which the Central Range forms directly from the accretionary prism, including the basement core, which originates from subducted, and then accreted, extended to hyper-extended continental crust.},
	issn = {0091-7613},
	doi = {10.1130/G34402.1},
	url = {https://doi.org/10.1130/G34402.1},
	author = {McIntosh, Kirk and van Avendonk, Harm and Lavier, Luc and Lester, W. Ryan and Eakin, Daniel and Wu, Francis and Liu, Char-Shine and Lee, Chao-Shing}
}
@article {sumy_mechanisms_2013,
	title = {The Mechanisms of Earthquakes and Faulting in the Southern Gulf of California},
	journal = {Bulletin of the Seismological Society of America},
	volume = {103},
	number = {1},
	year = {2013},
	pages = {487{\textendash}506},
	abstract = {Accurate earthquake locations and their focal mechanisms can illuminate the distribution and mode of deformation at rifted continental margins. The Pacific{\textendash}North America (Pa{\textendash}NA) plate boundary within the Gulf of California (GoC) provides an excellent opportunity to explore the evolution and kinematics of rifting, as continental extension in the north transitions to seafloor spreading in the south. From October 2005 to October 2006, an array of eight four-component ocean-bottom seismographs deployed in the GoC recorded seismicity as part of the Sea of Cortez Ocean-Bottom Array (SCOOBA) experiment. By combining the data with those from the onshore Network of Autonomously Recording Seismographs (NARS)-Baja array, we detect and locate \~{}700 earthquakes (Mw~2.2{\textendash}6.6) mainly along the northwest{\textendash}southeast-striking transform faults that delineate the plate boundary. For 36 events (Mw~3.5{\textendash}6.6) with high signal-to-noise ratio in a long-period (10{\textendash}20~s) band, we determine deviatoric moment tensors and associated double-couple focal mechanisms by regional waveform inversion. Many focal mechanisms are consistent with right-lateral strike-slip faulting along the Pa{\textendash}NA transform fault system, which suggests that the transform faults primarily accommodate seismic deformation within the gulf. In addition, we capture a swarm of events on Baja California along the right-lateral northwest{\textendash}southeast-striking Las Viboras{\textendash}El Azufre fault, which may be related to ongoing geothermal activity and volcanic deformation within the peninsula. The combination of high-resolution earthquake locations and focal mechanisms improves our understanding of the distribution of seismic deformation within the greater extensional zone in the southern GoC.Online Material: Earthquake catalog of the 695 events detected and located during our combined on-/offshore deployment of seismometers.},
	issn = {0037-1106},
	doi = {10.1785/0120120080},
	url = {https://doi.org/10.1785/0120120080},
	author = {Sumy, Danielle F. and Gaherty, James B. and Kim, Won-Young and Diehl, Tobias and Collins, John A.}
}
@article {mcguire_millimeter-level_2013,
	title = {Millimeter-level precision in a seafloor geodesy experiment at the Discovery transform fault, East Pacific Rise},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {14},
	number = {10},
	year = {2013},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/ggge.20225},
	pages = {4392{\textendash}4402},
	abstract = {Direct-path acoustic ranging is a promising seafloor geodetic technique for continuous high-resolution monitoring of geodynamical process such as fault slip and magma intrusion. Here we report on a yearlong acoustic ranging experiment conducted across the discovery transform fault at \~{}4{\textdegree}S on the East Pacific Rise. The ranging instruments utilized a novel acoustic signal designed to enhance precision. We find that, after correcting for variations in sound speed at the path end-points, the ranging measurements have a precision of \~{}1 mm over baselines approaching 1 km in length. The primary difficulty in this particular experiment was with the physical stability of the benchmarks, which were deployed free fall from a ship. Despite the stability issues, it appears that the portion of the transform fault that the array covered was locked during the year of our survey. The primary obstacle to continuous, high sample rate, high-precision geodetic monitoring of oceanic ridges and transform faults is now limited to the construction of geodetic monuments that are well anchored into bedrock.},
	keywords = {oceanic transform fault, seafloor geodesy},
	issn = {1525-2027},
	doi = {10.1002/ggge.20225},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ggge.20225},
	author = {McGuire, Jeffrey J. and Collins, John A.}
}
@article {worcester_north_2013,
	title = {The North Pacific Acoustic Laboratory deep-water acoustic propagation experiments in the Philippine Sea},
	journal = {The Journal of the Acoustical Society of America},
	volume = {134},
	number = {4},
	year = {2013},
	note = {Publisher: Acoustical Society of America},
	month = {oct},
	pages = {3359{\textendash}3375},
	abstract = {A series of experiments conducted in the Philippine Sea during 2009{\textendash}2011 investigated deep-water acoustic propagation and ambient noise in this oceanographically and geologically complex region: (i) the 2009 North Pacific Acoustic Laboratory (NPAL) Pilot Study/Engineering Test, (ii) the 2010{\textendash}2011 NPAL Philippine Sea Experiment, and (iii) the Ocean Bottom Seismometer Augmentation of the 2010{\textendash}2011 NPAL Philippine Sea Experiment. The experimental goals included (a) understanding the impacts of fronts, eddies, and internal tides on acoustic propagation, (b) determining whether acoustic methods, together with other measurements and ocean modeling, can yield estimates of the time-evolving ocean state useful for making improved acoustic predictions, (c) improving our understanding of the physics of scattering by internal waves and spice, (d) characterizing the depth dependence and temporal variability of ambient noise, and (e) understanding the relationship between the acoustic field in the water column and the seismic field in the seafloor. In these experiments, moored and ship-suspended low-frequency acoustic sources transmitted to a newly developed distributed vertical line array receiver capable of spanning the water column in the deep ocean. The acoustic transmissions and ambient noise were also recorded by a towed hydrophone array, by acoustic Seagliders, and by ocean bottom seismometers.},
	issn = {0001-4966},
	doi = {10.1121/1.4818887},
	url = {https://asa.scitation.org/doi/full/10.1121/1.4818887},
	author = {Worcester, Peter F. and Dzieciuch, Matthew A. and Mercer, James A. and Andrew, Rex K. and Dushaw, Brian D. and Baggeroer, Arthur B. and Heaney, Kevin D. and D{\textquoteright}Spain, Gerald L. and Colosi, John A. and Stephen, Ralph A. and Kemp, John N. and Howe, Bruce M. and Van Uffelen, Lora J. and Wage, Kathleen E.}
}
@article {godin_power_2013,
	title = {Power spectra of infragravity waves in a deep ocean},
	journal = {Geophysical Research Letters},
	volume = {40},
	number = {10},
	year = {2013},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/grl.50418},
	pages = {2159{\textendash}2165},
	abstract = {AbstractInfragravity waves (IGWs) play an important role in coupling wave processes in the ocean, ice shelves, atmosphere, and the solid Earth. Due to the paucity of experimental data, little quantitative information is available about power spectra of IGWs away from the shore. Here we use continuous, yearlong records of pressure at 28 locations on the seafloor off New Zealand{\textquoteright}s South Island to investigate spectral and spatial distribution of IGW energy. Dimensional analysis of diffuse IGW fields reveals universal properties of the power spectra observed at different water depths and leads to a simple, predictive model of the IGW spectra. While sources of IGWs off New Zealand are found to have a flat power spectrum, the IGW energy density has a pronounced dependence on frequency and local water depth as a result of the interaction of the waves with varying bathymetry.},
	keywords = {deep ocean, random wave fields, Surface gravity waves, wave spectra},
	issn = {1944-8007},
	doi = {10.1002/grl.50418},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/grl.50418},
	author = {Godin, Oleg A. and Zabotin, Nikolay A. and Sheehan, Anne F. and Yang, Zhaohui and Collins, John A.}
}
@article {wech_tectonic_2013,
	title = {Tectonic Tremor Recorded by Ocean Bottom Seismometers},
	journal = {Seismological Research Letters},
	volume = {84},
	number = {5},
	year = {2013},
	month = {sep},
	pages = {752{\textendash}758},
	issn = {0895-0695},
	doi = {10.1785/0220120184},
	url = {https://doi.org/10.1785/0220120184},
	author = {Wech, A. G. and Sheehan, A. F. and Boese, C. M. and Townend, J. and Stern, T. A. and Collins, J. A.}
}
@article {yang_character_2012,
	title = {The character of seafloor ambient noise recorded offshore New Zealand: Results from the MOANA ocean bottom seismic experiment},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {13},
	number = {10},
	year = {2012},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2012GC004201},
	abstract = {{We analyze the characteristics of ambient noise recorded on ocean-bottom seismographs using data from the 2009{\textendash}2010 MOANA (Marine Observations of Anisotropy Near Aotearoa) seismic experiment deployed west and east of South Island, New Zealand. Microseism and infragravity noise peaks are clear on data recorded on the vertical channel of the seismometer and on the pressure sensor. The noise levels in the infragravity band (<0.03 Hz) on the horizontal seismometer channels are too high to show the infragravity peak. There is a small difference (\~{}0.25 Hz versus \~{}0.2 Hz) in microseism peak frequencies between the two sides of the South Island on all three seismic channels. Our results show clear depth dependence between the peak frequency of infragravity waves and the water depth. We find that the product of water depth and wave number at the peak frequency is a constant},
	keywords = {continental shelf, infragravity wave, New Zealand, noise, OBS},
	issn = {1525-2027},
	doi = {10.1029/2012GC004201},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2012GC004201},
	author = {Yang, Zhaohui and Sheehan, Anne F. and Collins, John A. and Laske, Gabi}
}
@article {stachnik_determination_2012,
	title = {Determination of New Zealand Ocean Bottom Seismometer Orientation via Rayleigh-Wave Polarization},
	journal = {Seismological Research Letters},
	volume = {83},
	number = {4},
	year = {2012},
	pages = {704{\textendash}713},
	abstract = {Online material: Complete list of earthquakes used in this study.},
	issn = {0895-0695},
	doi = {10.1785/0220110128},
	url = {https://doi.org/10.1785/0220110128},
	author = {Stachnik, J. C. and Sheehan, A. F. and Zietlow, D. W. and Yang, Z. and Collins, J. and Ferris, A.}
}
@article {sutherland_middle_2012,
	title = {Middle Miocene to early Pliocene oblique extension in the southern Gulf of California},
	journal = {Geosphere},
	volume = {8},
	number = {4},
	year = {2012},
	month = {aug},
	pages = {752{\textendash}770},
	abstract = {A multichannel seismic (MCS) experiment spanning 600 km across the Alarc{\'o}n Rise and its conjugate rifted margins in the southern Gulf of California (western North America) provides insight into the spatial and temporal evolution of extension between Baja California and the mainland (Mexico). Stratigraphic analysis of multiple rift basins within the Alarc{\'o}n spreading corridor indicates an initial stage of oblique extension starting ca. 14{\textendash}12 Ma. This initial phase of extension was characterized by the formation of several large basins in the center of the gulf and on the southeast margin with negligible synrift sedimentation. A second phase of oblique extension, likely synchronous with large-scale basin opening in the central and northern Gulf of California, began ca. 8{\textendash}5 Ma and was characterized by the formation of smaller half-grabens distributed across the conjugate margins that contain both synrift and postrift deposits. A key feature imaged within the MCS data is a highly reflective, ropey layer at the top of basement, interpreted to be either volcanic rocks from the 25{\textendash}12 Ma Comond{\'u} Group, and/or early rifting volcanic rocks that are between 11 and 9 Ma, or younger. This volcanic layer is extensively faulted, suggesting that it predates the episode of early extension. Upper crustal extension appears to be equally distributed across conjugate margins, forming a symmetrical continental rift. Two styles of rifted basin are observed; older basins (estimated as 14{\textendash}11 Ma using sedimentation rates) show distributed extension with extensive basement faulting. In contrast, the younger basins (likely post{\textendash}6 Ma) are asymmetrical with synrift deposits thickening into the basin-bounding faults. The northeast-southwest geomorphic expression of the Tamayo bank and trough and other features provides additional evidence that northwest-southeast oblique extension began ca. 12 Ma. These new spatial and temporal constraints, when combined with a crustal thickness profile obtained across the entire Alarc{\'o}n corridor, suggest that significant northwest-southeast oblique extension within the Gulf of California started well before 6 Ma, in contrast to earlier models.},
	issn = {1553-040X},
	doi = {10.1130/GES00770.1},
	url = {https://doi.org/10.1130/GES00770.1},
	author = {Sutherland, Fiona H. and Kent, Graham M. and Harding, Alistair J. and Umhoefer, Paul J. and Driscoll, Neal W. and Lizarralde, Daniel and Fletcher, John M. and Axen, Gary J. and Holbrook, W. Steven and Gonz{\'a}lez-Fern{\'a}ndez, Antonio and Lonsdale, Peter}
}
@article {roland_seismic_2012,
	title = {Seismic velocity constraints on the material properties that control earthquake behavior at the Quebrada-Discovery-Gofar transform faults, East Pacific Rise},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {117},
	number = {B11},
	year = {2012},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2012JB009422},
	abstract = {Mid-ocean ridge transform faults (RTFs) vary strongly along strike in their ability to generate large earthquakes. This general observation suggests that local variations in material properties along RTFs exert a primary control on earthquake rupture dynamics. We explore these relationships by examining the seismic structure of two RTFs that have distinctly different seismic coupling. We determine the seismic velocity structure at the Gofar and Quebrada faults on the East Pacific Rise (EPR) using P wave traveltime tomography with data from two active-source wide-angle refraction lines crossing the faults. We image low-velocity zones (LVZs) at both faults, where P wave velocities are reduced by as much as 0.5{\textendash}1.0 km/s (\~{}10{\textendash}20\%) within a several kilometer wide region. At the Gofar fault, the LVZ extends through the entire crust, into the seismogenic zone. We rule out widespread serpentinization as an explanation for the low velocities, owing to the lack of a corresponding signal in the locally measured gravity field. The reduced velocities can be explained if the plate boundary region is composed of fault material with enhanced fluid-filled porosity (1.5{\textendash}8\%). Local seismic observations indicate that the high-porosity region lies within a \~{}10 km long portion of the fault that fails in large swarms of microearthquakes and acts as a barrier to the propagation of large (M \~{} 6.0) earthquakes. Tomographic images of fault structure combined with observed earthquake behavior suggest that EPR transform segments capable of generating large earthquakes have relatively intact gabbro within the seismogenic zone, whereas segments that slip aseismically or via earthquake swarms are composed of highly fractured, >=2 km wide damage zones that extend throughout the crust.},
	keywords = {fault structure, marine seismology, rupture dynamics, tomography, transform fault},
	issn = {2156-2202},
	doi = {10.1029/2012JB009422},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2012JB009422},
	author = {Roland, Emily and Lizarralde, Dan and McGuire, Jeffrey J. and Collins, John A.}
}
@article {collins_seismicity_2012,
	title = {Seismicity of the Atlantis Massif detachment fault, 30{\textdegree}N at the Mid-Atlantic Ridge},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {13},
	number = {10},
	year = {2012},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2012GC004210},
	abstract = {At the oceanic core complex that forms the Atlantis Massif at 30{\textdegree}N on the Mid-Atlantic Ridge, slip along the detachment fault for the last 1.5{\textendash}2 Ma has brought lower crust and mantle rocks to the seafloor. Hydroacoustic data collected between 1999 and 2003 suggest that seismicity occurred near the top of the Massif, mostly on the southeastern section, while detected seismicity along the adjacent ridge axis was sparse. In 2005, five short-period ocean bottom seismographs (OBS) were deployed on and around the Massif as a pilot experiment to help constrain the distribution of seismicity in this region. Analysis of six months of OBS data indicates that, in contrast to the results of the earlier hydroacoustic study, the vast majority of the seismicity is located within the axial valley. During the OBS deployment, and within the array, seismicity was primarily composed of a relatively constant background rate and two large aftershock sequences that included 5 teleseismic events with magnitudes between 4.0 and 4.5. The aftershock sequences were located on the western side of the axial valley adjacent to the Atlantis Massif and close to the ridge-transform intersection. They follow Omori{\textquoteright}s law, and constitute more than half of the detected earthquakes. The OBS data also indicate a low but persistent level of seismicity associated with active faulting within the Atlantis Massif in the same region as the hydroacoustically detected seismicity. Within the Massif, the data indicate a north-south striking normal fault, and a left-lateral, strike-slip fault near a prominent, transform-parallel, north-facing scarp. Both features could be explained by changes in the stress field at the inside corner associated with weak coupling on the Atlantis transform. Alternatively, the normal faulting within the Massif might indicate deformation of the detachment surface as it rolls over to near horizontal from an initial dip of about 60{\textdegree} beneath the axis, and the strike-slip events may indicate transform-parallel movement on adjacent detachment surfaces.},
	keywords = {Atlantis Massif, hydroacoustic, Mid-Atlantic Ridge, oceanic detachment fault, seismicity, T-phase},
	issn = {1525-2027},
	doi = {10.1029/2012GC004210},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2012GC004210},
	author = {Collins, John A. and Smith, Deborah K. and McGuire, Jeffrey J.}
}
@article {collins_shear_2012,
	title = {Shear wave splitting at the Hawaiian hot spot from the PLUME land and ocean bottom seismometer deployments},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {13},
	number = {2},
	year = {2012},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2011GC003881},
	abstract = {We examine upper mantle anisotropy across the Hawaiian Swell by analyzing shear wave splitting of teleseismic SKSwaves recorded by the PLUME broadband land and ocean bottom seismometer deployments. Mantle anisotropy beneath the oceans is often attributed to flow-induced lattice-preferred orientation of olivine. Splitting observations may reflect a combination of both fossil lithospheric anisotropy and anisotropy due to present-day asthenospheric flow, and here we address the question whether splitting provides diagnostic information on possible asthenospheric plume flow at Hawaii. We find that the splitting fast directions are coherent and predominantly parallel to the fossil spreading direction, suggesting that shear wave splitting dominantly reflects fossil lithospheric anisotropy. The signature of anisotropy from asthenospheric flow is more subtle, although it could add some perturbation to lithospheric splitting. The measured delay times are typically 1 s or less, although a few stations display larger splitting delays of 1{\textendash}2 s. The variability in the delay times across the different stations indicates differences in the degree of anisotropy or in the thickness of the anisotropic layer or in the effect of multilayer anisotropy. Regions with smaller splitting times may have experienced processes that modified the lithosphere and partially erased the fossil anisotropy; alternatively, asthenospheric splitting may either constructively add to or destructively subtract from lithospheric splitting to produce the observed variability in delay times.},
	keywords = {Hawaii, splittting},
	issn = {1525-2027},
	doi = {10.1029/2011GC003881},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2011GC003881},
	author = {Collins, John A. and Wolfe, Cecily J. and Laske, Gabi}
}
@article {kuo-chen_three-dimensional_2012,
	title = {Three-dimensional P velocity structures of the lithosphere beneath Taiwan from the analysis of TAIGER and related seismic data sets},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {117},
	number = {B6},
	year = {2012},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2011JB009108},
	abstract = {The convergence of the Philippine Sea and the Eurasian plates in the Taiwan region led to the formation of a young collisional mountain between two subduction zones of nearly orthogonal polarities. The geological processes underlying the collision and its relation to subduction are the primary targets of TAIGER (Taiwan Integrated Geodynamic Research) project. Newly acquired passive and active sources data on land, supplemented by ocean bottom as well as permanent seismic network data, are used to derive a new 3-D tomographic velocity model. Using the 7.5 km/sec contour as a marker for crustal deformation, two trend-parallel {\textquotedblleft}roots,{\textquotedblright} one under the Central Range with a maximum depth of 55 km and the other under the Coastal Range at 40 km, are found to extend from southern to central (\~{}24{\textdegree}N) Taiwan. Between the two roots and lying approximately beneath the Longitudinal Valley, the 7.5 km/sec contour rises to 25 km depth. In the upper mantle, a high velocity zone, east-dipping and its upper surface coinciding with a Wadati-Benioff zone in the south (\~{}22.8{\textdegree}N), becomes near vertical and ill-defined in the north (\~{}23.9{\textdegree}N). The crustal deformation as defined by the {\textquotedblleft}roots{\textquotedblright} and the along-trend variations of the upper mantle structures under Taiwan provide key information for the orogeny. With the thickening of crust to 55 km or more processes such as eclogitization and delamination may come into play.},
	keywords = {mountain building, seismic tomography, Taiwan orogeny},
	issn = {2156-2202},
	doi = {10.1029/2011JB009108},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2011JB009108},
	author = {Kuo-Chen, Hao and Wu, Francis T. and Roecker, Steven W.}
}
@article {mcguire_variations_2012,
	title = {Variations in earthquake rupture properties along the Gofar transform fault, East Pacific Rise},
	journal = {Nature Geoscience},
	volume = {5},
	number = {5},
	year = {2012},
	note = {Number: 5 Publisher: Nature Publishing Group},
	month = {may},
	pages = {336{\textendash}341},
	abstract = {Mid-ocean ridge transform faults experience more foreshocks than continental faults, yet the mainshock rarely ruptures the entire fault. Analysis of seismic data from the Gofar transform fault at the East Pacific Rise indicates that the foreshock region has different material properties from the mainshock region, and acts as a barrier to rupture propagation.},
	keywords = {seismology},
	issn = {1752-0908},
	doi = {10.1038/ngeo1454},
	url = {https://www.nature.com/articles/ngeo1454},
	author = {McGuire, Jeffrey J. and Collins, John A. and Gou{\'e}dard, Pierre and Roland, Emily and Lizarralde, Dan and Boettcher, Margaret S. and Behn, Mark D. and van der Hilst, Robert D.}
}
@article {bostock_wavefield_2012,
	title = {Wave-Field Decomposition of Ocean Bottom Seismograms},
	journal = {Bulletin of the Seismological Society of America},
	volume = {102},
	number = {4},
	year = {2012},
	month = {aug},
	pages = {1681{\textendash}1692},
	abstract = {Seismograms recorded on the seafloor are affected by reverberations in the overlying ocean layer. We examine the feasibility of removing these reverberations through a 1D wave-field decomposition based on a reflection{\textendash}transmission formulation of the problem. Two decomposition schemes are presented. The first scheme involves a simple manipulation of the fundamental matrix relating stress and displacement of plane harmonic waves to upgoing and downgoing wavevector coefficients and requires measurement of both ocean bottom displacement and pressure. The second approach involves only displacement recordings and knowledge of the water column depth. This latter quantity will generally be known a priori from deployment logs, or, alternatively, it may be estimated using vertical displacement and pressure seismograms in a preprocessing step. Both approaches require prior information on seabed properties. In the case of P-wave incidence, the decomposition depends primarily on the seabed S velocity β0. This quantity can be determined by examining trial decompositions over a range of β0{\textquoteright}s and selecting the value that minimizes the energy of the upgoing S-wave component at the arrival time of the incident wave. We apply this approach to synthetic seismograms for a simple Earth structure and to recordings of two large events from the Central Oregon Locked Zone Array (COLZA) on the continental margin of Oregon. The real data indicate that the wave-field decompositions are largely successful at lower frequencies (\&lt;0.1  Hz) but that 3D scattering, likely originating near the sediment{\textendash}basement contact, is manifested at higher frequencies.},
	issn = {0037-1106},
	doi = {10.1785/0120110162},
	url = {https://doi.org/10.1785/0120110162},
	author = {Bostock, M. G. and Trehu, A. M.}
}
@article {laske_asymmetric_2011,
	title = {Asymmetric shallow mantle structure beneath the Hawaiian Swell-evidence from Rayleigh waves recorded by the PLUME network},
	journal = {Geophysical Journal International},
	volume = {187},
	number = {3},
	year = {2011},
	pages = {1725{\textendash}1742},
	abstract = {We present models of the 3-D shear velocity structure of the lithosphere and asthenosphere beneath the Hawaiian hotspot and surrounding region. The models are derived from long-period Rayleigh-wave phase velocities that were obtained from the analysis of seismic recordings collected during two year-long deployments for the Hawaiian Plume-Lithosphere Undersea Mantle Experiment. For this experiment, broad-band seismic sensors were deployed at nearly 70 seafloor sites as well as 10 sites on the Hawaiian Islands. Our seismic images result from a two-step inversion of path-averaged dispersion curves using the two-station method. The images reveal an asymmetry in shear velocity structure with respect to the island chain, most notably in the lower lithosphere at depths of 60 km and greater, and in the asthenosphere. An elongated, 100-km-wide and 300-km-long low-velocity anomaly reaches to depths of at least 140 km. At depths of 60 km and shallower, the lowest velocities are found near the northern end of the island of Hawaii. No major velocity anomalies are found to the south or southeast of Hawaii, at any depth. The low-velocity anomaly in the asthenosphere is consistent with an excess temperature of 200-250 {\textdegree}C and partial melt at the level of a few percent by volume, if we assume that compositional variations as a result of melt extraction play a minor role. We also image small-scale low-velocity anomalies within the lithosphere that may be associated with the volcanic fields surrounding the Hawaiian Islands.},
	issn = {0956-540X},
	doi = {10.1111/j.1365-246X.2011.05238.x},
	url = {https://doi.org/10.1111/j.1365-246X.2011.05238.x},
	author = {Laske, Gabi and Markee, Amanda and Orcutt, John A. and Wolfe, Cecily J. and Collins, John A. and Solomon, Sean C. and Detrick, Robert S. and Bercovici, David and Hauri, Erik H.}
}
@article {dunn_contrasting_2011,
	title = {Contrasting crustal production and rapid mantle transitions beneath back-arc ridges},
	journal = {Nature},
	volume = {469},
	number = {7329},
	year = {2011},
	note = {Number: 7329 Publisher: Nature Publishing Group},
	pages = {198{\textendash}202},
	abstract = {The Eastern Lau spreading centre, located on the Lau back-arc basin hydrothermal vent system between Fiji and Tonga, is a focus site of the Ridge 2000 research programme of the US National Science Foundation. The first large-scale seismic study of the area reveals large and abrupt across- and along-strike changes in crustal properties, implying correspondingly large discontinuities in the nature of the mantle supplying melt to the ridge axes. The authors conclude that stable, broad triangular upwelling regions, as inferred for mid-ocean ridges, cannot form near the mantle wedge corner. Instead, the observations imply a dynamic process in which the ridge upwelling zone preferentially captures water-rich low-viscosity mantle when it is near the arc. As the ridge moves away from the arc, a tipping point is reached at which the material is rapidly released, resulting in rapid changes in the character of the crust formed at the ridge.},
	keywords = {seismology},
	issn = {1476-4687},
	doi = {10.1038/nature09690},
	url = {https://www.nature.com/articles/nature09690},
	author = {Dunn, Robert A. and Martinez, Fernando}
}
@article {wolfe_mantle_2011,
	title = {Mantle P-wave velocity structure beneath the Hawaiian hotspot},
	journal = {Earth and Planetary Science Letters},
	volume = {303},
	number = {3},
	year = {2011},
	month = {mar},
	pages = {267{\textendash}280},
	abstract = {Three-dimensional images of P-wave velocity structure beneath the Hawaiian Islands, obtained from a network of seafloor and land seismometers, show an upper-mantle low-velocity anomaly that is elongated in the direction of the island chain and surrounded by a high-velocity anomaly in the shallow upper mantle that is parabolic in map view. Low velocities continue downward to the mantle transition zone between 410 and 660km depth and extend into the topmost lower mantle, although the resolution of lower mantle structure from this data set is limited. Comparisons of inversions with separate data sets at different frequencies suggest that contamination by water reverberations is not markedly biasing the P-wave imaging of mantle structure. Many aspects of the P-wave images are consistent with independent tomographic images of S-wave velocity in the region, but there are some differences in upper mantle structure between P-wave and S-wave velocities. Inversions without station terms show a southwestward shift in the location of lowest P-wave velocities in the uppermost mantle relative to the pattern for shear waves, and inversions with station terms show differences between P-wave and S-wave velocity heterogeneity in the shallow upper mantle beneath and immediately east of the island of Hawaii. Nonetheless, the combined data sets are in general agreement with the hypothesis that the Hawaiian hotspot is the result of an upwelling, high-temperature plume. The broad upper-mantle low-velocity region beneath the Hawaiian Islands may reflect the diverging {\textquotedblleft}pancake{\textquotedblright} at the top of the upwelling zone; the surrounding region of high velocities could represent a downwelling curtain; and the low-velocity anomalies southeast of Hawaii in the transition zone and topmost lower mantle are consistent with predictions of plume tilt.},
	keywords = {finite-frequency tomography, Hawaii, hotspot, mantle plume},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2011.01.004},
	url = {https://www.sciencedirect.com/science/article/pii/S0012821X11000161},
	author = {Wolfe, Cecily J. and Solomon, Sean C. and Laske, Gabi and Collins, John A. and Detrick, Robert S. and Orcutt, John A. and Bercovici, David and Hauri, Erik H.}
}
@article {anchieta_seismicity_2011,
	title = {Seismicity around the Hawaiian Islands Recorded by the PLUME Seismometer Networks: Insight into Faulting near Maui, Molokai, and Oahu},
	journal = {Bulletin of the Seismological Society of America},
	volume = {101},
	number = {4},
	year = {2011},
	month = {aug},
	pages = {1742{\textendash}1758},
	abstract = {Instrumental limitations have long prevented the detailed characterization of offshore earthquakes around the Hawaiian Islands, and little is known about the spatial distribution of earthquakes in regions outside the vicinity of the well-monitored island of Hawaii. Here, we analyze data from the deployment of two successive networks of ocean-bottom seismometers (OBSs) as part of the Plume-Lithosphere Undersea Melt Experiment (PLUME) to better determine seismicity patterns along the Hawaiian Islands and their offshore regions. We find that earthquake detection rates are improved when seismograms are high-pass filtered above \~{}5 Hz to reduce the background seismic noise. Hypocentral solutions have been determined for 1147 previously undetected microearthquakes, and an additional 2880 events correspond to earthquakes already in the catalog of the United States Geological Survey (USGS) Hawaiian Volcano Observatory (HVO). The spatial patterns of earthquakes identified solely on the PLUME network provide complementary information to patterns identified by the HVO network. A diffuse pattern of seismicity is found to the southeast of the island of Hawaii, and clusters of earthquakes are located west of the island. Many microearthquakes are observed in the vicinity of Maui and Molokai, including some located at mantle depths. A small number of microearthquakes are found to occur near Oahu. There is no evidence from our analyses that the Molokai fracture zone (MFZ) is seismically active at this time, and no evidence was found of a previously hypothesized Diamond Head fault (DHF) near Oahu. However, on the basis of both the PLUME and HVO locations, there is a northeast{\textendash}southwest{\textendash}trending swath of epicenters extending northeastward of Oahu that may indicate the locus of moderate-sized historic earthquakes attributed to the Oahu region.},
	issn = {0037-1106},
	doi = {10.1785/0120100271},
	url = {https://doi.org/10.1785/0120100271},
	author = {Anchieta, Maria C. and Wolfe, Cecily J. and Pavlis, Gary L. and Vernon, Frank L. and Eakins, Jennifer A. and Solomon, Sean C. and Laske, Gabi and Collins, John A.}
}
@article {williams_seismicity_2011,
	title = {Seismicity at the Cascadia Plate Boundary beneath the Oregon Continental Shelf},
	journal = {Bulletin of the Seismological Society of America},
	volume = {101},
	number = {3},
	year = {2011},
	pages = {940{\textendash}950},
	abstract = {Since 2003, 39 small earthquakes have been detected off the coast of central Oregon in the nominally locked part of the Cascadia subduction zone, where very little seismic activity has been recorded in spite of a paleoseismic record of great subduction events. Although the regional earthquake bulletin reports depths of 29 and 28~km for the two largest events (Mw~4.9 and Mw~4.7, which occurred in 2004), analysis by Tr{\'e}hu et~al. (2008) indicates that they were low-angle thrust events that occurred on the plate boundary at depths of 9{\textendash}11 and 16~km, respectively. Because of sparse onshore station coverage, most of the smaller events have large location uncertainties. Double-difference relative location of 30 of these earthquakes reveals two tight clusters approximately 30~km apart; each cluster is associated with one of the two larger events. Within each cluster, relocation reduces the hypocenter depth spread from \&gt;15 km to \&lt;3 km, with uncertainties on the order of 0.1~km. The relocations, combined with independent absolute hypocenter locations for two 2008 events using a deployment of land and ocean-bottom seismometers, suggest that the seismicity occurred at plate boundary depths, possibly on the Cascadia megathrust. This concentrated activity in the seismogenic zone may represent patches on the fault plane with anomalous frictional characteristics, possibly caused by subducted topographic features, which can affect the propagation of a large megathrust rupture.},
	issn = {0037-1106},
	doi = {10.1785/0120100198},
	url = {https://doi.org/10.1785/0120100198},
	author = {Williams, Mark C. and Tr{\'e}hu, Anne M. and Braunmiller, Jochen}
}
@article {van_avendonk_structure_2011,
	title = {Structure and serpentinization of the subducting Cocos plate offshore Nicaragua and Costa Rica},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {12},
	number = {6},
	year = {2011},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2011GC003592},
	abstract = {The Cocos plate experiences extensional faulting as it bends into the Middle American Trench (MAT) west of Nicaragua, which may lead to hydration of the subducting mantle. To estimate the along strike variations of volatile input from the Cocos plate into the subduction zone, we gathered marine seismic refraction data with the R/V Marcus Langseth along a 396 km long trench parallel transect offshore of Nicaragua and Costa Rica. Our inversion of crustal and mantle seismic phases shows two notable features in the deep structure of the Cocos plate: (1) Normal oceanic crust of 6 km thickness from the East Pacific Rise (EPR) lies offshore Nicaragua, but offshore central Costa Rica we find oceanic crust from the northern flank of the Cocos Nazca (CN) spreading center with more complex seismic velocity structure and a thickness of 10 km. We attribute the unusual seismic structure offshore Costa Rica to the midplate volcanism in the vicinity of the Gal{\'a}pagos hot spot. (2) A decrease in Cocos plate mantle seismic velocities from \~{}7.9 km/s offshore Nicoya Peninsula to \~{}6.9 km/s offshore central Nicaragua correlates well with the northward increase in the degree of crustal faulting outboard of the MAT. The negative seismic velocity anomaly reaches a depth of \~{}12 km beneath the Moho offshore Nicaragua, which suggests that larger amounts of water are stored deep in the subducting mantle lithosphere than previously thought. If most of the mantle low velocity zone can be interpreted as serpentinization, the amount of water stored in the Cocos plate offshore central Nicaragua may be about 2.5 times larger than offshore Nicoya Peninsula. Hydration of oceanic lithosphere at deep sea trenches may be the most important mechanism for the transfer of aqueous fluids to volcanic arcs and the deeper mantle.},
	keywords = {Central America, Cocos Plate, Gal{\'a}pagos hot spot, plate bending and faulting, seismic velocities, subduction},
	issn = {1525-2027},
	doi = {10.1029/2011GC003592},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2011GC003592},
	author = {Van Avendonk, H. J. A. and Holbrook, W. S. and Lizarralde, D. and Denyer, P.}
}
@article {yao_structure_2011,
	title = {Structure of young East Pacific Rise lithosphere from ambient noise correlation analysis of fundamental- and higher-mode Scholte-Rayleigh waves},
	journal = {Nouveaux d{\'e}veloppements de l{\textquoteright}imagerie et du suivi temporel {\`a} partir du bruit sismique},
	volume = {343},
	number = {8},
	year = {2011},
	month = {sep},
	pages = {571{\textendash}583},
	abstract = {Inter-station Green{\textquoteright}s functions estimated from ambient noise studies have been widely used to investigate crustal structure. However, most studies are restricted to continental areas and use fundamental-mode surface waves only. In this study, we recover inter-station surface (Scholte-Rayleigh) wave empirical Green{\textquoteright}s function (EGFs) of both the fundamental- and the first-higher mode using one year of continuous seismic noise records on the vertical component from 28 ocean bottom seismographs deployed in the Quebrada/Discovery/Gofar transform faults region on the East Pacific Rise. The average phase-velocity dispersion of the fundamental mode (period band 2{\textendash}30s) and the first-higher mode (period band 3{\textendash}7s) from all EGFs are used to invert for the 1-D average, shear-velocity structure in the crust and uppermost mantle using a model-space search algorithm. The preferred shear-velocity models reveal low velocities (4.29km/s) between Moho and 25km depth below sea-surface, suggesting the absence of a fast uppermost mantle lid in this young (0{\textendash}2Myr) oceanic region. An even more pronounced low-velocity zone, with shear velocities \~{}3.85km/s, appears at a depth between 25{\textendash}40km below sea-surface. Along with previous results, our study indicates that the shear velocity in the uppermost oceanic mantle increases with increasing seafloor age, consistent with age-related lithospheric cooling. R{\'e}sum{\'e} Les fonctions de Green estim{\'e}es {\`a} partir de l{\textquoteright}analyse du bruit ambiant ont beaucoup {\'e}t{\'e} utilis{\'e}es pour {\'e}tudier la structure de la cro{\^u}te terrestre. La plupart de ces travaux sont toutefois limit{\'e}s aux zones continentales, et ne consid{\`e}rent que le mode fondamental des ondes de surface. Dans cette {\'e}tude, les fonctions de Green empiriques (EGFs) du mode fondamental et du premier mode sup{\'e}rieur des ondes de surface (Scholte-Rayleigh) sont reconstruites {\`a} partir d{\textquoteright}une ann{\'e}e d{\textquoteright}enregistrements continus de la composante verticale du bruit sismique sur 28 ocean bottom seismometers (OBSs) d{\'e}ploy{\'e}s dans la r{\'e}gion des failles transformantes Quebrada/Discovery/Gofar, le long de la dorsale oc{\'e}anique du Pacifique Est. La dispersion moyenne des vitesses de phase du mode fondamental (dans la bande de p{\'e}riode 2{\textendash}30s) et du premier mode sup{\'e}rieur (dans la bande 3{\textendash}7s), issus des EGFs, est utilis{\'e}e pour d{\'e}terminer un mod{\`e}le moyen 1D de la vitesse des ondes de cisaillement dans la cro{\^u}te et le manteau sup{\'e}rieur {\`a} partir d{\textquoteright}un algorithme de recherche dans l{\textquoteright}espace mod{\`e}le. Le mod{\`e}le de vitesse des ondes de cisaillement r{\'e}sultant pr{\'e}sente une couche de faible vitesse (4,29km/s) entre le Moho et 25km sous le niveau de la mer, ce qui sugg{\`e}re l{\textquoteright}absence de couche superficielle rapide dans le manteau sup{\'e}rieur de cette jeune r{\'e}gion oc{\'e}anique (0{\textendash}2millions d{\textquoteright}ann{\'e}es). Une zone de faible vitesse encore plus prononc{\'e}e, avec une vitesse de cisaillement de \~{}3,85km/s, appara{\^\i}t entre 25 et 40km sous le niveau de la mer. Combin{\'e}e avec des r{\'e}sultats ant{\'e}rieurs, notre {\'e}tude montre que la vitesse de cisaillement dans le manteau oc{\'e}anique sup{\'e}rieur augmente avec l{\textquoteright}{\^a}ge du fond oc{\'e}anique, ce qui est en accord avec le refroidissement dans le temps de la lithosph{\`e}re.},
	keywords = {ambient noise, Bruit ambiant, Dorsale Est Pacifique, East Pacific Rise, Fundamental- and higher-mode Scholte-Rayleigh waves, Lithosphere, Low-velocity zone, Manteau oc{\'e}anique sup{\'e}rieur, Modes fondamental et sup{\'e}rieur des ondes de Scholte-Rayleigh, Oceanic Uppermost Mantle, Zone de faible vitesse},
	issn = {1631-0713},
	doi = {10.1016/j.crte.2011.04.004},
	url = {https://www.sciencedirect.com/science/article/pii/S1631071311000952},
	author = {Yao, Huajian and Gou{\'e}dard, Pierre and Collins, John A. and McGuire, Jeffrey J. and van der Hilst, Robert D.}
}
@article {bezada_subduction_2010,
	title = {Subduction in the southern Caribbean: Images from finite-frequency P wave tomography},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {115},
	number = {B12},
	year = {2010},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2010JB007682},
	abstract = {The eastern boundary of the Caribbean plate is marked by subduction of the Atlantic under the Lesser Antilles. The southeastern plate boundary is characterized by a strike-slip margin, while different configurations of subduction of the southwest Caribbean under South America have been proposed. We investigate the slab geometry in the upper mantle using multiple-frequency, teleseismic P wave tomography. Waveforms from P and PKPdf phases from 285 (Mb > 5.0) events occurring at epicentral distances from 30{\textdegree} to 90{\textdegree} and greater than 150{\textdegree} were bandpass filtered and cross-correlated to obtain up to three sets of delay times for each event. The delay times were inverted using approximate first Fresnel zone sensitivity kernels. Our results show the subducting Atlantic slab, as well as a second slab in the west of the study area that we interpret as a subducting fragment of the Caribbean plate. Both slabs have steep dips where imaged and can be traced to depths greater than 600 km. These results are consistent with transition zone boundary topography as determined by receiver function analysis. The Atlantic slab extends continent-ward south of the plate bounding strike-slip margin. We interpret this extension as continental margin lithospheric mantle that is detaching from beneath South America and subducting along with the oceanic Atlantic slab. The steep subduction of the Caribbean occurs \~{}500 km landward from the trench, implying an initial stage of shallow subduction as far to the east as the Lake Maracaibo-M{\'e}rida Andes region, as has been inferred from intermediate depth seismicity.},
	keywords = {P-wave tomography, southern Caribbean, subduction},
	issn = {2156-2202},
	doi = {10.1029/2010JB007682},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2010JB007682},
	author = {Bezada, M. J. and Levander, A. and Schmandt, B.}
}
@article {leahy_underplating_2010,
	title = {Underplating of the Hawaiian Swell: evidence from teleseismic receiver functions},
	journal = {Geophysical Journal International},
	volume = {183},
	number = {1},
	year = {2010},
	month = {oct},
	pages = {313{\textendash}329},
	abstract = {The Hawaiian Islands are the canonical example of an age-progressive island chain, formed by volcanism long thought to be fed from a hotspot source that is more or less fixed in the mantle. Geophysical data, however, have so far yielded contradictory evidence on subsurface structure. The substantial bathymetric swell is supportive of an anomalously hot upper mantle, yet seafloor heat flow in the region does not appear to be enhanced. The accumulation of magma beneath pre-existing crust (magmatic underplating) has been suggested to add chemical buoyancy to the swell, but to date the presence of underplating has been constrained only by local active-source experiments. In this study, teleseismic receiver functions derived from seismic events recorded during the PLUME project were analysed to obtain a regional map of crustal structure for the Hawaiian Swell. This method yields results that compare favourably with those from previous studies, but permits a much broader view than possible with active-source seismic experiments. Our results indicate that the crustal structure of the Hawaiian Islands is quite complicated and does not conform to the standard model of sills fed from a central source. We find that a shallow P-to-s conversion, previously hypothesized to result from the volcano-sediment interface, corresponds more closely to the boundary between subaerial and subaqueous extrusive material. Correlation between uplifted bathymetry at ocean-bottom-seismometer locations and presence of underplating suggests that much of the Hawaiian Swell is underplated, whereas a lack of underplating beneath the moat surrounding the island of Hawaii suggests that underplated crust outward of the moat has been fed from below by dykes through the lithosphere rather than by sills spreading from the island centre. Local differences in underplating may reflect focusing of magma-filled dykes in response to stress from volcanic loading. Finally, widespread underplating adds chemical buoyancy to the swell, reducing the amplitude of a mantle thermal anomaly needed to match bathymetry and supporting observations of normal heat flow.},
	issn = {0956-540X},
	doi = {10.1111/j.1365-246X.2010.04720.x},
	url = {https://doi.org/10.1111/j.1365-246X.2010.04720.x},
	author = {Leahy, Garrett M. and Collins, John A. and Wolfe, Cecily J. and Laske, Gabi and Solomon, Sean C.}
}
@article {stephen_deep_2009,
	title = {Deep seafloor arrivals: An unexplained set of arrivals in long-range ocean acoustic propagation},
	journal = {The Journal of the Acoustical Society of America},
	volume = {126},
	number = {2},
	year = {2009},
	note = {Publisher: Acoustical Society of America},
	month = {aug},
	pages = {599{\textendash}606},
	abstract = {Receptions, from a ship-suspended source (in the band 50{\textendash}100Hz 50 {\textendash} 100 Hz ) to an ocean bottom seismometer (about 5000m 5000 m depth) and the deepest element on a vertical hydrophone array (about 750m 750 m above the seafloor) that were acquired on the 2004 Long-Range Ocean Acoustic Propagation Experiment in the North Pacific Ocean, are described. The ranges varied from 50to3200km 50 to 3200 km . In addition to predicted ocean acoustic arrivals and deep shadow zone arrivals (leaking below turning points), {\textquotedblleft}deep seafloor arrivals,{\textquotedblright} that are dominant on the seafloor geophone but are absent or very weak on the hydrophone array, are observed. These deep seafloor arrivals are an unexplained set of arrivals in ocean acoustics possibly associated with seafloor interface waves.},
	issn = {0001-4966},
	doi = {10.1121/1.3158826},
	url = {https://asa.scitation.org/doi/full/10.1121/1.3158826},
	author = {Stephen, Ralph A. and Bolmer, S. Thompson and Dzieciuch, Matthew A. and Worcester, Peter F. and Andrew, Rex K. and Buck, Linda J. and Mercer, James A. and Colosi, John A. and Howe, Bruce M.}
}
@article {wolfe_mantle_2009,
	title = {Mantle Shear-Wave Velocity Structure Beneath the Hawaiian Hot Spot},
	journal = {Science},
	volume = {326},
	number = {5958},
	year = {2009},
	note = {Publisher: American Association for the Advancement of Science},
	month = {dec},
	pages = {1388{\textendash}1390},
	abstract = {Defining the mantle structure that lies beneath hot spots is important for revealing their depth of origin. Three-dimensional images of shear-wave velocity beneath the Hawaiian Islands, obtained from a network of sea-floor and land seismometers, show an upper-mantle low-velocity anomaly that is elongated in the direction of the island chain and surrounded by a parabola-shaped high-velocity anomaly. Low velocities continue downward to the mantle transition zone between 410 and 660 kilometers depth, a result that is in agreement with prior observations of transition-zone thinning. The inclusion of SKS observations extends the resolution downward to a depth of 1500 kilometers and reveals a several-hundred-kilometer-wide region of low velocities beneath and southeast of Hawaii. These images suggest that the Hawaiian hot spot is the result of an upwelling high-temperature plume from the lower mantle.},
	doi = {10.1126/science.1180165},
	url = {https://www.science.org/doi/full/10.1126/science.1180165},
	author = {Wolfe, Cecily J. and Solomon, Sean C. and Laske, Gabi and Collins, John A. and Detrick, Robert S. and Orcutt, John A. and Bercovici, David and Hauri, Erik H.}
}
@article {miller_upper_2009,
	title = {Upper mantle structure beneath the Caribbean-South American plate boundary from surface wave tomography},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {114},
	number = {B1},
	year = {2009},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2007JB005507},
	abstract = {We have measured shear wave velocity structure of the crust and upper mantle of the Caribbean-South American boundary region by analysis of fundamental mode Rayleigh waves in the 20- to 100-s period band recorded at the BOLIVAR/GEODINOS stations from 2003 to 2005. The model shows lateral variations that primarily correspond to tectonic provinces and boundaries. A clear linear velocity change parallels the plate bounding dextral strike-slip fault system along the northern coast of Venezuela, illustrating the differences between the South American continental lithosphere, the Venezuelan archipelago, and the Caribbean oceanic lithosphere. At depths up to 120 km beneath the Venezuelan Andes and the Maracaibo block, there is evidence of underthrusting of the Caribbean plate, but there is no other evidence of subduction of the Caribbean plate beneath the South American plate. In eastern Venezuela, linear crustal low velocities are associated with the fold and thrust belts whereas as higher crustal velocities are imaged in the Guayana shield lithosphere. The subducting oceanic part of the South American plate is imaged beneath the Antilles arc. The surface wave images combined with seismicity data suggest shear tearing of the oceanic lithosphere away from the buoyant continental South American plate offshore of northeastern Venezuela. The continental lithosphere south of the slab tear is bent down toward the plate boundary in response to the propagating tear in the lithosphere. We interpret a nearly vertical low-velocity {\textquotedblleft}column{\textquotedblright} west of the tear centered beneath the Cariaco Basin, with three-dimensional asthenospheric flow around the southern edge of the subducting oceanic lithosphere, with the asthenosphere escaping from beneath continental South America and rising into the plate boundary zone. The complex plate boundary structure is best examined in three dimensions. We discuss the new surface wave tomographic inversion in the context of results from other researchers including local seismicity, teleseismic shear wave splits, and interpretations from active source profiling.},
	keywords = {plate boundary, surface wave tomography, upper mantle structure},
	issn = {2156-2202},
	doi = {10.1029/2007JB005507},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2007JB005507},
	author = {Miller, Meghan S. and Levander, Alan and Niu, Fenglin and Li, Aibing}
}
@article {clark_characterizing_2008,
	title = {Characterizing the Caribbean{\textendash}South American plate boundary at 64{\textdegree}W using wide-angle seismic data},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {113},
	number = {B7},
	year = {2008},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2007JB005329},
	abstract = {We present wide-angle velocity modeling results from profile 64{\textdegree}W of the Broadband Ocean-Land Investigation of Venezuela and the Antilles arc Region (BOLIVAR) project. Line 64W is a 460-km-long, approximately north-south, onshore-offshore reflection/refraction transect located approximately at 64{\textdegree}W longitude. The profile extends across the transform plate boundary between the southeastern Caribbean (CAR) and South American (SA) plates. East of the profile the plate boundary bends to the north, and SA subducts beneath CAR. We utilize first-arrival tomography to resolve a smooth velocity field for the sediments and upper/middle crust and then use a layered approach to resolve a sharp velocity contrast for the Moho, simultaneously inverting refracted Pn and reflected PmP arrivals. We image crustal and upper mantle structure across the plate boundary zone. We interpret that the strike-slip system that accommodates relative motion between CAR and SA extends near vertically through the entire crust and offsets the Moho. We see no evidence supporting a major component of convergence, and rather than a wide boundary zone of overlapping lithospheric plates, we interpret the plate boundary to be confined to the 33-km-wide, near-vertical strike-slip system. Previously interpreted thrust faults flanking the strike-slip system appear to be confined to the upper/middle crust and may be related to the detachment of subducting South American lithosphere at the southern terminus of the Lesser Antilles subduction zone east of 64{\textdegree}W.},
	keywords = {El Pilar, velocity modeling, Venezuela margin},
	issn = {2156-2202},
	doi = {10.1029/2007JB005329},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2007JB005329},
	author = {Clark, S. A. and Zelt, C. A. and Magnani, M. B. and Levander, A.}
}
@article {christeson_crustal_2008,
	title = {Crustal structure of the Caribbean{\textendash}northeastern South America arc-continent collision zone},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {113},
	number = {B8},
	year = {2008},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2007JB005373},
	abstract = {We present the results of a 568-km-long regional wide-angle seismic profile conducted in the southeastern Caribbean that crosses an active island arc, a remnant arc, two basins possibly floored by oceanic crust, an allochthonous terrane of forearc affinity, and the passive margin of northern South America. The velocity structures of the Late Cretaceous Aves Ridge remnant arc and Miocene and younger Lesser Antilles arc are remarkably similar, which implies that magmatic processes have remained moderately steady over time. Crustal thickness is \~{}26 km at the Aves Ridge and \~{}24 km at the Lesser Antilles arc. In comparison to the Izu-Bonin and Aleutian arcs, the Lesser Antilles arc is thinner and has no evidence for a lower crustal cumulate layer, which is consistent with the estimated low magma production rates of the Lesser Antilles arc. Crustal thickness beneath the Grenada and Tobago basins is 4{\textendash}10 km, and the velocity structure suggests that these basins could be floored by oceanic crust. A decrease of \~{}1 km/s in average seismic velocity of the upper crust is observed from NW to SE across the North Coast fault zone; we argue that this marks the suture between the far-traveled Caribbean arc and the passive margin of the South American continent. Current strike-slip motion between the Caribbean and South American plates is located \~{}30 km to the south, and thus material originally deposited on the South American passive margin has now been transferred to the Caribbean plate.},
	keywords = {arc-continent collision, Lesser Antilles, SE Caribbean},
	issn = {2156-2202},
	doi = {10.1029/2007JB005373},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2007JB005373},
	author = {Christeson, Gail L. and Mann, Paul and Escalona, Alejandro and Aitken, Trevor J.}
}
@article {holmes_crustal_2008,
	title = {Crustal thickness variations along the Southeast Indian Ridge (100{\textdegree}{\textendash}116{\textdegree}E) from 2-D body wave tomography},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {9},
	number = {12},
	year = {2008},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2008GC002152},
	abstract = {Axial morphology along the Southeast Indian Ridge (SEIR) systematically changes from an axial high to a deep rift valley at a nearly uniform intermediate spreading rate between 100{\textdegree}{\textendash}116{\textdegree}E, west of the Australian-Antarctic Discordance (AAD). Basalt geochemistry has a consistent Indian{\textendash}mid-ocean ridge basalt (MORB) type isotopic signature, so changes in axial topography are attributed to variations in both mantle temperature and melt supply. Wide-angle seismic refraction lines were shot to four ocean bottom hydrophones within SEIR segments P1, P2, S1, and T, where each segment is characterized by a different morphology. We constructed 2-D crustal velocity models by jointly inverting hand-picked P wave refraction (Pg) and Moho reflection (PmP) traveltime data using a top-down, minimum-structure methodology. The results show a 1.5 km eastward decrease in crustal thickness across the study area, with segment averages ranging from 6.1 km at P1 to 4.6 km at T. Melt generation models require a \~{}30{\textdegree}C decrease in mantle temperature toward the AAD to account for the crustal thickness trend. Significant changes in axial morphology accompany small-scale variations in crustal thickness, consistent with models of crustal accretion where ridge topography is determined by a balance between mantle temperature, melt supply, and cooling from hydrothermal circulation. Layer 3 thins by 3.0 km as layer 2 thickens by 1.4 km between segments P1 and T, reflecting the eastward decrease in melt supply and increase in melt lens depth. The trade-off in seismic layers may be explained by models relating the increase in overburden pressure on a deepening melt lens to the volume of magma erupted into the upper crust rather than cooling at depth to form new lower crustal material.},
	keywords = {crustal structure, mid-ocean ridge, oceanic crust, seismic refraction, seismic tomography, Southeast Indian Ridge},
	issn = {1525-2027},
	doi = {10.1029/2008GC002152},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2008GC002152},
	author = {Holmes, R. Chadwick and Tolstoy, Maya and Cochran, James R. and Floyd, Jacqueline S.}
}
@article {clark_identification_2008,
	title = {Identification and tectonic implications of a tear in the South American plate at the southern end of the Lesser Antilles},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {9},
	number = {11},
	year = {2008},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2008GC002084},
	abstract = {In the southeast corner of the Caribbean, westward subduction of (Atlantic) oceanic South America beneath the Lesser Antilles transitions to east-west transform motion between continental South America and the Caribbean plate. This geometry requires negatively buoyant, subducting, oceanic South American lithosphere to progressively detach from positively buoyant, continental South American lithosphere. The most widely accepted model is slab break-off, with oblique arc-continent collision and northwest dipping, continental subduction precipitating narrow rifting in the subducting slab. In contrast, the subduction-transform edge propagator (STEP) model conceptualizes progressive detachment along a vertical, dip-slip tear through the lithosphere, with stress focused at the edge of the propagating transform boundary. We present four types of seismic data to resolve the ongoing lithospheric detachment: local seismicity, receiver functions, wide-angle seismic velocity inversion, and a regional, balanced cross section constrained by petroleum industry data. These four data sets image a near-vertical tear extending through the entire lithosphere, revealing a key mechanism for the structural evolution of Venezuela.},
	keywords = {jelly sandwich, lithospheric detachment, mantle dynamics, slab break-off, STEP, tear},
	issn = {1525-2027},
	doi = {10.1029/2008GC002084},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2008GC002084},
	author = {Clark, S. A. and Sobiesiak, M. and Zelt, C. A. and Magnani, M. B. and Miller, M. S. and Bezada, M. J. and Levander, A.}
}
@article {clark_negligible_2008,
	title = {Negligible convergence and lithospheric tearing along the Caribbean{\textendash}South American plate boundary at 64{\textdegree}W},
	journal = {Tectonics},
	volume = {27},
	number = {6},
	year = {2008},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2008TC002328},
	abstract = {Prior studies of the Caribbean{\textendash}South American plate boundary have suffered from poor constraint on the structure of the crust and uppermost mantle. We use a recent wide-angle velocity model from the Broadband Ocean-Land Investigation of Venezuela and the Antilles arc Region project to constrain new seismic reflection data and previously published line drawing interpretations of the Caribbean{\textendash}South American plate boundary at 64{\textdegree}W. Though commonly characterized as obliquely convergent, we determine that convergence is negligible in our study area. Previous estimates of Miocene to present north-south shortening onshore eastern Venezuela have commonly been 115 km or higher, but we constrain shortening to \~{}35 km onshore, with an additional \~{}30 km offshore. With such minor convergence, we conclude that uplift and basin subsidence in eastern Venezuela does not derive from typical collisional orogeny. Instead, the largely vertical tectonics likely result from mantle dynamics associated with an eastward propagating, near-vertical tear in the lithosphere along the former passive margin.},
	keywords = {El Pilar fault, Serrania del Interior, STEP fault},
	issn = {1944-9194},
	doi = {10.1029/2008TC002328},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2008TC002328},
	author = {Clark, S. A. and Levander, A. and Magnani, M. B. and Zelt, C. A.}
}
@article {calvert_three-dimensional_2008,
	title = {Three-dimensional crustal structure of the Mariana island arc from seismic tomography},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {113},
	number = {B1},
	year = {2008},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2007JB004939},
	abstract = {A three-dimensional (3-D) seismic refraction survey was acquired over the Mariana volcanic arc at 14.5{\textendash}18.5{\textdegree}N and 145{\textendash}147{\textdegree}E. First-arrival traveltimes from this survey and from a separate 2-D survey acquired approximately perpendicular to the arc have been simultaneously inverted for a 3-D P wave velocity model using seismic tomography subject to smoothness constraints. The active arc, which initiated only 3{\textendash}4 Ma ago, has an average crustal thickness of 18 km. Approximately 40 km to the east the inactive remnant of the rifted Eocene arc has an average crustal thickness of 21 km, due primarily to a thicker lower-crustal layer with velocities of 6.5{\textendash}7.0 km s-1. Crustal production clearly varies both temporally and spatially, with some crustal layers, including the igneous fore-arc crust, varying in thickness by a factor of up to 2 along strike. Average P wave velocities within the upper crust of the modern arc are 240{\textendash}360 m s-1 lower than in the Eocene arc but are 280 m s-1 higher within the lower crust. Middle crust with velocities of 6.0{\textendash}6.5 km s-1 is best developed beneath the Eocene arc. These results suggest an evolution of arc structure with increasing age: We infer closure of fractures and porosity in the upper crust through hydrothermal circulation and a reduction in the mafic character of the middle to lower crust as a result of intracrustal differentiation. Although tonalitic rocks may predominate in the transition from upper to middle crust, the bulk of the crust is essentially basaltic.},
	keywords = {crust, Mariana arc, seismic tomography},
	issn = {2156-2202},
	doi = {10.1029/2007JB004939},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2007JB004939},
	author = {Calvert, Andrew J. and Klemperer, Simon L. and Takahashi, Narumi and Kerr, Bryan C.}
}
@article {canales_crustal_2007,
	title = {Crustal structure of the Trans-Atlantic Geotraverse (TAG) segment (Mid-Atlantic Ridge, 26{\textdegree}10'N): Implications for the nature of hydrothermal circulation and detachment faulting at slow spreading ridges},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {8},
	number = {8},
	year = {2007},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2007GC001629},
	abstract = {New seismic refraction data reveal that hydrothermal circulation at the Trans-Atlantic Geotraverse (TAG) hydrothermal field on the Mid-Atlantic Ridge at 26{\textdegree}10'N is not driven by energy extracted from shallow or mid-crustal magmatic intrusions. Our results show that the TAG hydrothermal field is underlain by rocks with high seismic velocities typical of lower crustal gabbros and partially serpentinized peridotites at depth as shallow as 1 km, and we find no evidence for low seismic velocities associated with mid-crustal magma chambers. Our tomographic images support the hypothesis of Tivey et al. (2003) that the TAG field is located on the hanging wall of a detachment fault, and constrain the complex, dome-shaped subsurface geometry of the fault system. Modeling of our seismic velocity profiles indicates that the porosity of the detachment footwall increases after rotation during exhumation, which may enhance footwall cooling. However, heat extracted from the footwall is insufficient for sustaining long-term, high-temperature, hydrothermal circulation at TAG. These constraints indicate that the primary heat source for the TAG hydrothermal system must be a deep magma reservoir at or below the base of the crust.},
	keywords = {crustal structure, detachment faulting, Mid-Atlantic Ridge, slow spreading ridge, TAG hydrothermal field},
	issn = {1525-2027},
	doi = {10.1029/2007GC001629},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2007GC001629},
	author = {Canales, J. Pablo and Sohn, Robert A. and deMartin, Brian J.}
}
@article {demartin_kinematics_2007,
	title = {Kinematics and geometry of active detachment faulting beneath the Trans-Atlantic Geotraverse (TAG) hydrothermal field on the Mid-Atlantic Ridge},
	journal = {Geology},
	volume = {35},
	number = {8},
	year = {2007},
	month = {aug},
	pages = {711{\textendash}714},
	abstract = {Newly acquired seismic refraction and microearthquake data from the Trans-Atlantic Geotraverse (TAG) segment of the Mid-Atlantic Ridge at 26{\textdegree}N reveal for the first time the geometry and seismic character of an active oceanic detachment fault. Hypocenters from 19,232 microearthquakes observed during an eight month ocean bottom seismometer deployment form an \~{}15-km-long, dome-shaped fault surface that penetrates to depths \&gt;7 km below the seafloor on a steeply dipping (\~{}70{\textdegree}) interface. A tomographic model of compressional-wave velocities demonstrates that lower crustal rocks are being exhumed in the detachment footwall, which appears to roll over to a shallow dip of 20{\textdegree} {\textpm} 5{\textdegree} and become aseismic at a depth of \~{}3 km. Outboard of the detachment the exhumed lithosphere is deformed by ridge-parallel, antithetical normal faulting. Our results suggest that hydrothermal fluids at the TAG field exploit the detachment fault to extract heat from a region near the crust-mantle interface over long periods of time.},
	issn = {0091-7613},
	doi = {10.1130/G23718A.1},
	url = {https://doi.org/10.1130/G23718A.1},
	author = {deMartin, Brian J. and Sohn, Robert A. and Pablo Canales, Juan and Humphris, Susan E.}
}
@article {niu_receiver_2007,
	title = {Receiver function study of the crustal structure of the southeastern Caribbean plate boundary and Venezuela},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {112},
	number = {B11},
	year = {2007},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2006JB004802},
	abstract = {We have investigated crustal thickness and composition across the southeastern Caribbean plate boundary with the receiver function technique. We used teleseismic data recorded by a temporary broadband array deployed under the BOLIVAR project and the permanent national seismic network of Venezuela. We used the primary P-to-S conversion and crustal reverberations to estimate crustal thickness and average crustal VP/VS ratio over the region. We observe large variations in crustal thickness and Poisson{\textquoteright}s ratio. Estimated Moho depth ranges from \~{}16 km beneath the southeastern Caribbean Sea to \~{}52 km beneath northeastern Venezuela and the Venezuelan Andes. There is a good correlation between crustal structure and tectonic terranes. Data from the Precambrian Guayana Shield suggest that the underlying crustal structure is relatively uniform with a moderate thickness (\~{}37 km) and an intermediate composition. A thick crust is found below the foreland basins. The two mountain systems in northern Venezuela, the Serrania del Interior and the Serrania del Falcon, have a thin crust with arc composition and are likely dynamically supported by elastic rebound or underthrusting of the oceanic plateau that characterizes the southern Caribbean. On the other hand, the Venezuelan Andes and Perija Range on the western side of the country are probably isostatically balanced by thick crustal roots.},
	keywords = {Moho depth, southeast Caribbean, VP/VS ratio},
	issn = {2156-2202},
	doi = {10.1029/2006JB004802},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2006JB004802},
	author = {Niu, Fenglin and Bravo, Tammy and Pavlis, Gary and Vernon, Frank and Rendon, Herbert and Bezada, Maximiliano and Levander, Alan}
}
@article {lizarralde_variation_2007,
	title = {Variation in styles of rifting in the Gulf of California},
	journal = {Nature},
	volume = {448},
	number = {7152},
	year = {2007},
	note = {Number: 7152 Publisher: Nature Publishing Group},
	month = {jul},
	pages = {466{\textendash}469},
	abstract = {Results from the PESCADOR seismic experiment in the Gulf of California provide new insight into rifting {\textemdash} the process that ruptures continents and forms new ocean basins. Unpredicted variations in magmatic activity in continental rifts are commonly attributed to variations in mantle temperature, but such thermal variations tend to occur over large length scales. The new results reveal large differences in rifting style and magmatism over short lateral distances. This suggests that the observed range in magmatism is caused not by variation in temperature, but rather by variability in mantle composition and fertility {\textemdash} the intrinsic capacity of the underlying mantle to produce melt.},
	keywords = {Humanities and Social Sciences, multidisciplinary, Science},
	issn = {1476-4687},
	doi = {10.1038/nature06035},
	url = {https://www.nature.com/articles/nature06035},
	author = {Lizarralde, Daniel and Axen, Gary J. and Brown, Hillary E. and Fletcher, John M. and Gonz{\'a}lez-Fern{\'a}ndez, Antonio and Harding, Alistair J. and Holbrook, W. Steven and Kent, Graham M. and Paramo, Pedro and Sutherland, Fiona and Umhoefer, Paul J.}
}
@article {shillington_composition_2004,
	title = {Composition and structure of the central Aleutian island arc from arc-parallel wide-angle seismic data},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {5},
	number = {10},
	year = {2004},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2004GC000715},
	abstract = {New results from wide-angle seismic data collected parallel to the central Aleutian island arc require an intermediate to mafic composition for the middle crust and a mafic to ultramafic composition for the lower crust and yield lateral velocity variations that correspond to arc segmentation and trends in major element geochemistry. The 3-D ray tracing/2.5-D inversion of this sparse wide-angle data set, which incorporates independent phase interpretations and new constraints on shallow velocity structure, produces a faster and smoother result than a previously published velocity model. Middle-crustal velocities of 6.5{\textendash}7.3 km/s over depths of \~{}10{\textendash}20 km indicate an andesitic to basaltic composition. High lower-crustal velocities of 7.3{\textendash}7.7 km/s over depths of \~{}20{\textendash}35 km are interpreted as ultramafic-mafic cumulates and/or garnet granulites. The total crustal thickness is 35{\textendash}37 km. This result indicates that the Aleutian island arc has higher velocities, and thus more mafic compositions, than average continental crust, implying that significant modifications would be required for this arc to be a suitable building block for continental crust. Lateral variations in average crustal velocity (below 10 km) roughly correspond to trends in major element geochemistry of primitive (Mg \# > 0.6) lavas. The highest lower-crustal velocities (and presumably most mafic material) are detected in the center of an arc segment, between Unmak and Unalaska Islands, implying that arc segmentation exerts control over crustal composition.},
	keywords = {continental crust, crustal geophysics, island arc, major element geochemistry},
	issn = {1525-2027},
	doi = {10.1029/2004GC000715},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2004GC000715},
	author = {Shillington, Donna J. and Van Avendonk, Harm J. A. and Holbrook, W. Steven and Kelemen, Peter B. and Hornbach, Matthew J.}
}
@article {konter_seafloor_2004,
	title = {Seafloor seismic monitoring of an active submarine volcano: Local seismicity at Vailulu{\textquoteright}u Seamount, Samoa},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {5},
	number = {6},
	year = {2004},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2004GC000702},
	abstract = {We deployed five ocean bottom hydrophones (OBHs) for a 1-year seismic monitoring study of Vailulu{\textquoteright}u Seamount, the youngest and easternmost volcano in the Samoan Archipelago. Four instruments were placed on the summit crater rim at 600{\textendash}700 m water depth, and one was placed inside the crater at 1000 m water depth. An analysis of the first 45 days of records shows a very large number of seismic events, 211 of them local. These events define a steady background activity of about four seismic events per day, increasing to about 10 events per day during a week of heightened seismic activity, which peaked at 40 events during 1 day. We identified 107 earthquakes, whose arrivals could be picked on all five stations and that are likely located within the seamount, based on their similar waveforms. Two linear trends are defined by 21 of these events. These are extremely well correlated and located, first downward then upward on a steeply inclined plane that is close to the axial plane of the southeast rift as it emerges from the main summit of Vailulu{\textquoteright}u. These events resemble volcanotectonic earthquakes from subaerial volcanoes in displaying very coherent seismic waveforms and by showing systematic, narrowly defined progressions in hypocenter locations. We propose that these events reflect brittle rock failure due to magma redistribution in or near a central magma reservoir.},
	keywords = {Samoa, seismic monitoring, submarine, Vailulu{\textquoteright}u, volcanic activity, volcano},
	issn = {1525-2027},
	doi = {10.1029/2004GC000702},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2004GC000702},
	author = {Konter, J. G. and Staudigel, H. and Hart, S. R. and Shearer, P. M.}
}
@article {okaya_imaging_2003,
	title = {Imaging a plate boundar using double-sided onshore-offshore seismic profiling},
	journal = {The Leading Edge},
	volume = {22},
	number = {3},
	year = {2003},
	month = {mar},
	pages = {256{\textendash}260},
	issn = {1070-485X},
	doi = {10.1190/1.1564531},
	url = {https://doi.org/10.1190/1.1564531},
	author = {Okaya, David and Stern, Tim and Holbrook, Steve and van Avendonk, Harm and Davey, Fred and Henrys, Stuart}
}
