@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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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.}
}
@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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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}
}
@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 {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}
}
@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}
}
@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}
}
@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 {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 {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.}
}
@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}
}
@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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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}
}
