@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 {cortes-rivas_interactions_2025,
	title = {Interactions between megathrust behavior and forearc deformation in the Andreanof segment of the Aleutian Subduction Zone, offshore Alaska, USA},
	journal = {Geology},
	year = {2025},
	note = {_eprint: https://pubs.geoscienceworld.org/gsa/geology/article-pdf/doi/10.1130/G52810.1/7093527/g52810.pdf},
	abstract = {To explore controls on megathrust behavior and its connection with forearc deformation, we studied the Andreanof segment of the Aleutian Subduction Zone (offshore Alaska, USA), which has a simple geological history as a relatively young intra-oceanic subduction zone. Here, the forearc shows greater uplift and compression in the strongly coupled Adak region compared to the weakly coupled Atka region. Using multichannel seismic reflection data, we found that the incoming plate in both regions exhibits similar characteristics along the segment, suggesting that its properties do not account for the varying megathrust behavior and forearc deformation. Instead, differences between the Atka and Adak regions in the thickness of the methane hydrate stability zone, as marked by a bottom-simulating reflector, suggest more heat advection, and thus dewatering, in the Adak region, where the more developed fault network may enable fluid drainage, thereby lowering pore pressure at the megathrust and promoting coupling. Higher coupling allows for seismic and stress cycling that would sustain forearc permeability by faulting. Our results suggest a feedback between deformation and coupling that may be active or latent in other more complex subduction zones but in concert with or masked by other factors.},
	issn = {0091-7613},
	doi = {10.1130/G52810.1},
	url = {https://doi.org/10.1130/G52810.1},
	author = {Cort{\'e}s-Rivas, Valeria and Shillington, Donna J. and Lizarralde, Dan and Mark, Hannah}
}
@article {park_low-velocity_2025,
	title = {Low-velocity anomaly in the Coral Sea associated with subducting slabs and the Woodlark rift},
	journal = {Communications Earth \& Environment},
	volume = {6},
	number = {1},
	year = {2025},
	pages = {184},
	abstract = {Classical plume models offer insights into intraplate volcanism and seamount chain formation by assuming a cylindrical upwelling of hot materials from the core-mantle boundary. The interaction of mantle plumes with ridges or subducting slabs disrupts typical plate tectonics, leading to distinctive tectonic phenomena such as ridge jumps or slab stagnation. However, thermal plume models sometimes fall short in explaining perplexing tectonic features, necessitating consideration of compositional heterogeneities within mantle plumes. Here, using multimode waveform tomography, we identify a large, vertically divergent low-velocity anomaly in the upper mantle beneath the Coral Sea in the southwestern Pacific, which circumvents the remnants of subducting slabs toward northeastern Australia with intraplate volcanism, and the Woodlark rift, the most rapidly extending continental rift. Our findings furnish seismic evidence for the widespread propagation of a thermochemical mantle plume spanning over 10{\textdegree} at depths of 270{\textendash}410 km, facilitating its simultaneous contacts with slabs and rifts.},
	issn = {2662-4435},
	doi = {10.1038/s43247-025-02166-8},
	url = {https://doi.org/10.1038/s43247-025-02166-8},
	author = {Park, Ji-hoon and Chang, Sung-Joon}
}
@article {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 {atkins_hydroacoustic_2024,
	title = {Hydroacoustic Evidence for Offshore Lava Emplacement During the 2018 Kilauea Eruption},
	journal = {Geophysical Research Letters},
	volume = {51},
	number = {20},
	year = {2024},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024GL110885},
	month = {10/2024},
	pages = {e2024GL110885},
	abstract = {During the 2018 Kilauea eruption, over half the erupted lava was deposited on the seafloor. Lava flows crossing the shoreline generated sounds that were recorded by a network of hydrophones. We show that short-duration, broadband signals associated with lava-water interactions occurred throughout the eruption but increased in number when the Ahalanui ocean entry initiated on July 11. These terminated in early August coincident with the eruption{\textquoteright}s end. We compare hydroacoustic data with transmission loss models and eruption photographs to show that coastal explosive activity was poorly recorded by the hydrophone network. Similarly, strong hydroacoustic signals did not correlate with observed activity. These results suggest that acoustic signals were generated by lava flowing up to 100 s of meters offshore. Offshore lava flows can be hazardous to boaters, but hydrophones provide a means by which these hazards can be detected.},
	keywords = {hydrophone, hydrovolcanic, Kilauea, lava-water interaction},
	issn = {1944-8007},
	doi = {10.1029/2024GL110885},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2024GL110885},
	author = {Atkins, C. and Costa, O. and Caplan-Auerbach, J.}
}
@article {jian_hydrothermal_2024,
	title = {Hydrothermal flow and serpentinization in oceanic core complexes controlled by mafic intrusions},
	journal = {Nature Geoscience},
	year = {2024},
	note = {Publisher: Nature Publishing Group},
	pages = {1{\textendash}6},
	abstract = {Deep-sea hydrothermal systems at slow/ultraslow-spreading mid-ocean ridges are often located within ultramafic rocks that are part of oceanic core complexes. These complexes contain lower-crustal and mantle sections exhumed due to detachment faulting. Hydrothermal circulation in these environments leads to massive sulfide deposits, hydration of oceanic lithosphere and conditions resembling early Earth{\textquoteright}s life origin. However, the relationship between hydrothermal pathways in these environments and crustal and mantle lithologies, faulting, magmatism, serpentinization and alteration is poorly understood. Here we present seismic models of a Mid-Atlantic Ridge core complex and its ultramafic-hosted hydrothermal system derived from full waveform inversion of controlled-source seismic data and from local earthquake tomography. The models and derived rock properties reveal high-permeability channels within serpentinized peridotite along the flanks of the core complex. These channels converge beneath active and fossil hydrothermal fields and are diverted around mechanically strong, impermeable shallow mafic intrusions (2{\textendash}3 km wide, \textasciitilde1 km thick), causing hydrothermal outflow and the formation of massive sulfide deposits around the intrusions{\textquoteright} edges. These mafic intrusions also act as lids that limit fluid downflow{\textemdash}and thus serpentinization{\textemdash}in the centre of the core complex. Our results demonstrate that hydrothermal flow in ultramafic settings is controlled by lithology contacts, with mafic intrusions modulating hydrothermal pathways and extent of mantle serpentinization at depth.},
	keywords = {3706 Geophysics, Economic geology, Element cycles, Geodynamics, Tectonics},
	issn = {1752-0908},
	doi = {10.1038/s41561-024-01444-y},
	url = {https://www.nature.com/articles/s41561-024-01444-y},
	author = {Jian, Hanchao and Canales, J. Pablo and Dunn, Robert and Nedimovi{\'c}, Mladen R.}
}
@article {chen_mid-lithospheric_2024,
	title = {A Mid-Lithospheric Discontinuity Detected Beneath 155 Ma Western Pacific Seafloor Using Sp Receiver Functions},
	journal = {Geophysical Research Letters},
	volume = {51},
	number = {5},
	year = {2024},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2024GL108347},
	pages = {e2024GL108347},
	abstract = {This study probes the lithosphere-asthenosphere system beneath 155 Ma Pacific seafloor using teleseismic S-to-p receiver functions at the Pacific Lithosphere Anisotropy and Thickness Experiment project ocean-bottom-seismometers. Within the lithosphere, a significant velocity decrease at 33{\textendash}50 km depth is observed. This mid-lithospheric discontinuity is consistent with the velocity contrast between the background mantle and thin, trapped layers of crystallized partial melt, in the form of either dolomite or garnet granulite. These melts possibly originated from deeper asthenospheric melting beneath the flanks of spreading centers, and were transported within the cooling lithosphere. A positive velocity increase of 3\%{\textendash}6\% is observed at 130{\textendash}155 km depth and is consistent with the base of a layer with partial melt in the asthenosphere. A shear velocity decrease associated with the lithosphere-asthenosphere boundary at 95{\textendash}115 km depth is permitted by the data, but is not required.},
	keywords = {oceanic lithosphere and asthenosphere, old western Pacific, partial melt, PLATE OBS array, Sp receiver function},
	issn = {1944-8007},
	doi = {10.1029/2024GL108347},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2024GL108347},
	author = {Chen, K.-X. and Forsyth, D. W. and Fischer, K. M.}
}
@article {cones_offshore_2024,
	title = {Offshore windfarm construction elevates metabolic rate and increases predation vulnerability of a key marine invertebrate},
	journal = {Environmental Pollution},
	volume = {360},
	year = {2024},
	month = {11/2024},
	pages = {124709},
	abstract = {A global increase in offshore windfarm development is critical to our renewable energy future. Yet, widespread construction plans have generated substantial concern for impacts to co-occurring organisms and the communities they form. Pile driving construction, prominent in offshore windfarm development, produces among the highest amplitude sounds in the ocean creating widespread concern for a diverse array of taxa. However, studies addressing ecologically key species are generally lacking and most research is disparate, failing to integrate across response types (e.g., behavior, physiology, and ecological interactions), particularly in situ. The lack of integrative field studies presents major challenges to understand or mitigate actual impacts of offshore wind development. Here, we examined critical behavioral, physiological, and antipredator impacts of actual pile driving construction on the giant sea scallop (Placopecten magellanicus). Benthic taxa including bivalves are of particular concern because they are sound-sensitive, cannot move appreciable distances away from the stressor, and support livelihoods as one of the world{\textquoteright}s most economically and socially important fisheries. Overall, pile driving sound impacted scallops across a series of behavioral and physiological assays. Sound-exposed scallops consistently reduced their valve opening (22\%), resulting in lowered mantle water oxygen levels available to the gills. Repeated and rapid valve adductions led to a 56\% increase in metabolic rates relative to pre-exposure baselines. Consequently, in response to predator stimuli, sound-exposed scallops displayed a suite of significantly weaker antipredator behaviors including fewer swimming events and shorter time-to-exhaustion. These results show aquatic construction activities can induce metabolic and ecologically relevant changes in a key benthic animal. As offshore windfarm construction accelerates globally, our field-based study highlights that spatial overlap with benthic taxa may cause substantial metabolic changes, alter important fisheries resources, and ultimately could lead to increased predation.},
	keywords = {Metabolism, noise, Predation, Scallop, Sound pollution},
	issn = {0269-7491},
	doi = {10.1016/j.envpol.2024.124709},
	url = {https://www.sciencedirect.com/science/article/pii/S0269749124014234},
	author = {Cones, Seth F. and J{\'e}z{\'e}quel, Youenn and Jarriel, Sierra and Aoki, Nad{\`e}ge and Brewer, Hannah and Collins, John and Chauvaud, Laurent and Mooney, T. Aran}
}
@article {chen_origin_2024,
	title = {On the Origin of the Hawaiian Swell: Lithosphere and Asthenosphere Seismic Structure From Rayleigh Wave Dispersion},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {129},
	number = {7},
	year = {2024},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2024JB029407},
	month = {07/2024},
	pages = {e2024JB029407},
	abstract = {In this study, we revisit the shear-wave velocity structure of the lithosphere and asthenosphere surrounding the Hawaiian hotspot and Hawaiian swell using Rayleigh wave data spanning periods of 20{\textendash}125 s from the PLUME project. A primary goal of this investigation is to probe the origin of the Hawaiian swell and the mechanism that elevates the topography, providing insights into mantle dynamics beneath hotspot swells. In the shear velocity model, the 30{\textendash}70 km depth range is largely featureless with weak and local anomalies, indicating that the elevation of the Hawaiian swell cannot be attributed to upper lithospheric reheating or replacement. In contrast, at 80{\textendash}150 km depth, a pronounced region of anomalously low velocities is well-resolved, with the lowest velocities found beneath the Hawaii-Maui-Molokai part of the island chain. Minimum shear velocities are approximately 4.0 km/s at 100{\textendash}120 km depth, which is an \~{}8\%-10\% velocity decrease relative to the surrounding velocities away from the swell. This pattern suggests that hot, buoyant mantle from deeper plume sources laterally spread out near the top of the normal oceanic asthenosphere. We find that the low-velocity pattern in the asthenosphere exhibits a strong correlation with the overall shape of the Hawaiian swell topography. Assuming that density anomalies are proportional to shear velocity anomalies, we demonstrate that the anomalous elevation of the swell can be explained by the uplift of a 30-km-thick elastic plate loaded from below by this buoyant, low-seismic-velocity layer in the asthenosphere.},
	keywords = {Hawaiian swell, lithosphere and asthenosphere, oceanic hotspot, Rayleigh wave, shear-wave velocity, two-plane wave method},
	issn = {2169-9356},
	doi = {10.1029/2024JB029407},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2024JB029407},
	author = {Chen, Kai-Xun and Forsyth, Donald W.}
}
@article {rebeyrol_revisiting_2024,
	title = {Revisiting the OBS seafloor compliance signal removal with a stationarity and stacking-based approach: the BRUIT-FM toolbox},
	journal = {Geophysical Journal International},
	volume = {239},
	year = {2024},
	month = {10/2024},
	pages = {386{\textendash}401},
	abstract = {This study focuses on improving the seafloor compliance noise removal method, which relies on estimates of the compliance transfer function frequency response (the deformation of the seafloor under long-period pressure waves). We first propose a new multi-scale deviation analysis of broadband ocean bottom seismometer data to evaluate stationarity properties that are key to the subsequent analysis. We then propose a new approach to removing the compliance noise from the vertical channel data, by stacking daily estimated transfer function frequency responses over a period of time. We also propose an automated transient event detection and data selection method based on a cross-correlation criterion. As an example, we apply the method to data from the Cascadia Initiative (network 7D2011). We find that the spectral extent of long-period forcing waves varies significantly over time so that standard daily transfer function calculation techniques poorly estimate the transfer function frequency response at the lowest frequencies, resulting in poor denoising performance. The proposed method more accurately removes noise at these lower frequencies, especially where coherence is low, reducing the mean deviation of the signal in our test case by 27 \% or more. We also show that our calculated transfer functions can be transfered across time periods. The method should allow better estimates of seafloor compliance and help to remove compliance noise at stations with low pressure-acceleration coherence. Our results can be reproduced using the BRUIT-FM Python toolbox, available at https://gitlab.ifremer.fr/anr-bruitfm/bruit-fm-toolbox.},
	issn = {1365-246X},
	doi = {10.1093/gji/ggae265},
	url = {https://doi.org/10.1093/gji/ggae265},
	author = {Rebeyrol, Simon and Ker, St{\'e}phan and Duval, Laurent and Crawford, Wayne C}
}
@article {acquisto_structural_2024,
	title = {Structural Controls on Megathrust Slip Behavior Inferred From a 3D, Crustal-Scale, P-Wave Velocity Model of the Alaska Peninsula Subduction Zone},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {129},
	number = {11},
	year = {2024},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024JB029632},
	pages = {e2024JB029632},
	abstract = {Abstract In subduction zones, along-strike and downdip variations in megathrust slip behavior are linked to changes in properties of the subducting and overriding plates. Although marine geophysical methods provide insights into subduction zone structures, most surveys consist of sparse 2D profiles, limiting our understanding of first-order controls. Here, we use active-source seismic data to derive a 3D crustal-scale P-wave velocity model of the Alaska Peninsula subduction zone that encompasses both plates and spans the Semidi segment and SW Kodiak asperity. Our results reveal modest variations within the incoming plate, attributed to a series of fracture zones, seamounts and their associated basement swell, collectively contributing to plate hydration. Basement swell appears to modulate the distribution and type of sediment entering the trench, likely impacting observed variations in slip behavior. The overriding plate exhibits significant heterogeneity. The updip limit and width of the dynamic backstop are similar between the SW Kodiak asperity and eastern Semidi segment, but differ significantly from the Western Semidi segment. These distinctions likely account for differences in earthquake rupture patterns and interseismic coupling among these segments. Additionally, high-velocities in the mid-lower forearc crust coincide with the location of megathrust slip during the Mw 8.2 2021 Chignik event. We interpret these velocities as intracrustal intrusions that contributed to the deep rupture of the 2021 event. Our findings suggest that the contrasting structural and material properties of both the incoming and overriding plates influence the spatially complex and semi-persistent segmentation of the megathrust offshore the Alaska Peninsula.},
	doi = {https://doi.org/10.1029/2024JB029632},
	author = {Acquisto, T. and B{\'e}cel, A. and Canales, J. P. and Beauc{\'e}, E.}
}
@article {carbotte_subducting_2024,
	title = {Subducting plate structure and megathrust morphology from deep seismic imaging linked to earthquake rupture segmentation at Cascadia},
	journal = {Science Advances},
	volume = {10},
	number = {23},
	year = {2024},
	note = {_eprint: https://www.science.org/doi/pdf/10.1126/sciadv.adl3198},
	pages = {eadl3198},
	abstract = {The origin of rupture segmentation along subduction zone megathrusts and linkages to the structural evolution of the subduction zone are poorly understood. Here, regional-scale seismic imaging of the Cascadia margin is used to characterize the megathrust spanning 900 km from Vancouver Island to the California border, across the seismogenic zone to a few tens of kilometers from the coast. Discrete domains in lower plate geometry and sediment underthrusting are identified, not evident in prior regional plate models, which align with changes in lithology and structure of the upper plate and interpreted paleo-rupture patches. Strike-slip faults in the lower plate associated with oblique subduction mark boundaries between regions of distinct lower plate geometry. Their formation may be linked to changes in upper plate structure across long-lived upper plate faults. The Juan de Fuca plate is fragmenting within the seismogenic zone at Cascadia as the young plate bends beneath the heterogeneous upper plate resulting in structural domains that coincide with paleo-rupture segmentation. A fragmented lower plate in the Cascadia seismogenic zone bounds structural domains linked to paleo-rupture segmentation.},
	doi = {10.1126/sciadv.adl3198},
	author = {Carbotte, Suzanne M. and Boston, Brian and Han, Shuoshuo and Shuck, Brandon and Beeson, Jeffrey and Canales, J. Pablo and Tobin, Harold and Miller, Nathan and Nedimovic, Mladen and Tr{\'e}hu, Anne and Lee, Michelle and Lucas, Madelaine and Jian, Hanchao and Jiang, Danqi and Moser, Liam and Anderson, Chris and Judd, Darren and Fernandez, Jaime and Campbell, Chuck and Goswami, Antara and Gahlawat, Rajendra}
}
@article {lindner_bayesian_2023,
	title = {Bayesian regional moment tensor from ocean bottom seismograms recorded in the Lesser Antilles: implications for regional stress field},
	journal = {Geophysical Journal International},
	volume = {233},
	number = {2},
	year = {2023},
	month = {12/2022},
	pages = {1036{\textendash}1054},
	abstract = {Seismic activity in the Lesser Antilles (LA) is characterized by strong regional variability along the arc reflecting the complex subduction setting and history. Although routine seismicity monitoring can rely on an increasing number of island stations, the island-arc setting means that high-resolution monitoring and detailed studies of fault structures require a network of ocean bottom seismometers (OBS). As part of the 2016{\textendash}2017 Volatile recycling at the Lesser Antilles arc (VoiLA) project, we deployed 34 OBS stations in the forearc and backarc. During the deployment time, 381 events were recorded within the subduction zone. In this paper, we perform full-waveform regional moment tensor (RMT) inversions, to gain insight into the stress distribution along the arc and at depth. We developed a novel inversion approach, AmΦB{\textemdash}{\textquoteleft}Amphibious Bayesian{\textquoteright}, taking into account uncertainties associated with OBS deployments. Particularly, the orientation of horizontal components (alignment uncertainty) and the high noise level on them due to ocean microseisms are accounted for using AmΦB. The inversion is conducted using a direct, uniform importance sampling of the fault parameters within a multidimensional tree structure: the uniXtree-sampling algorithm. We show that the alignment of the horizontal OBS components, particularly in high noise level marine environments, influences the obtained source mechanism when using standard least-squares (L2) RMT inversion schemes, resulting in systematic errors in the recovered focal mechanisms including high artificial compensated linear vector dipole (CLVD) contributions. Our Bayesian formulation in AmΦB reduces these CLVD components by nearly 60~per~cent and the aberration of the focal geometry as measured by the Kagan angle by around 40~per~cent relative to a standard L2 inversion. Subsequently, we use AmΦB-RMT to obtain 45 (Mw \&gt; 3.8) regional MT solutions, out of which 39 are new to any existing database. Combining our new results with existing solutions, we subsequently analyse a total of 151 solutions in a focal mechanism classification (FMC) diagram and map them to the regional tectonic setting. We also use our newly compiled RMT database to perform stress tensor inversions along the LA subduction zone. On the plate interface, we observe the typical compressional stress regime of a subduction zone and find evidence for upper-plate strike slip and normal fault behaviour in the north that becomes a near arc-perpendicular extensional stress regime towards the south. A dominant slab perpendicular extensional stress regime is found in the slab at 100{\textendash}200~km beneath the central part of the arc. We interpret this stress condition to be a result of slab pull varying along the arc due to partial slab detachment along previously hypothesized lateral slab tear near Grenada, at the southern end of the LA arc, leading to reactivation of pre-existing structures around the subducted Proto-Caribbean ridge.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggac494},
	url = {https://doi.org/10.1093/gji/ggac494},
	author = {Lindner, Mike and Rietbrock, Andreas and Bie, Lidong and Goes, Saskia and Collier, Jenny and Rychert, Catherine and Harmon, Nicholas and Hicks, Stephen P and Henstock, Tim and the VoiLA working group}
}
@article {canales_casie21-obs_2023,
	title = {CASIE21-OBS: An Open-Access, OBS Controlled-Source Seismic Data Set for Investigating the Structure and Properties of the Cascadia Accretionary Wedge and the Downgoing Explorer-Juan de Fuca-Gorda Plate System},
	journal = {Seismological Research Letters},
	volume = {94},
	year = {2023},
	note = {Publisher: Seismological Society of America (SSA)},
	month = {07/2023},
	pages = {2093{\textendash}2109},
	abstract = {Geological processes at subduction zones and their associated geohazards (e.g., megathrust earthquakes, submarine landslides, tsunamis, and arc volcanism) are, to a large extent, controlled by the structure, physical properties and fluid content of the subducting plate, the accreted sediments, and the overriding plate. In these settings, modern seismic modeling and imaging techniques based on controlled-source, multicomponent ocean-bottom seismometer (OBS) data are some of the best tools available for determining the subseafloor elastic properties, which can be linked to the aforementioned properties. Here, we present CASIE21-OBS, a controlled-source marine wide-angle OBS data set recently collected across the Cascadia convergent margin as part of the larger CAscadia Seismic Imaging Experiment 2021 (CASIE21). The main component of CASIE21 is a long-offset multichannel seismic (MCS) survey of the Cascadia margin conducted in June{\textendash}July 2021 onboard R/V M.G. Langseth (cruise MGL2104) aiming to characterize the incoming plate, the plate interface geometry and properties, and the overlying sediment stratigraphy and physical properties. CASIE21-OBS was conducted during R/V M.G. Langseth cruise MGL2103 (May 2021) and R/V Oceanus cruise OC2106A (June{\textendash}July 2021). It consisted of 63 short-period four-component OBSs deployed at a total 120 stations along 10 across-trench profiles extending from \~{}50 km seaward of the deformation front to the continental shelf, and from offshore northern Vancouver Island to offshore southern Oregon. The OBSs recorded the airgun signals of the CASIE21-MCS survey as well as natural seismicity occurring during the deployment period (24 May 2021 19:00 UTC{\textendash}9 July 2021 09:00 UTC). The OBS data are archived and available at the Incorporated Research Institutions for Seismology Data Management Center under network code YR_2021 for continuous time series (miniSEED) and identifier 21-008 for assembled data set (SEG-Y).},
	keywords = {3706 Geophysics},
	issn = {0895-0695},
	doi = {10.1785/0220230010},
	author = {Canales, Juan Pablo and Miller, Nathaniel C. and Baldwin, Wayne and Carbotte, Suzanne M. and Han, Shuoshuo and Boston, Brian and Jian, Hanchao and Collins, John and Lizarralde, Dan}
}
@article {xu_constraints_2023,
	title = {Constraints on the structure of the oceanic crust of the Tamu Massif by teleseismic P-wave coda autocorrelation},
	journal = {Frontiers in Earth Science},
	volume = {11},
	year = {2023},
	abstract = {The Tamu Massif, considered the biggest single volcano on Earth, was formed by the accumulation of enormous amounts of magma erupting to the surface. It is the largest and oldest seamount in Shatsky Rise, which is the third largest oceanic plateau on Earth. However, the formation mechanism of Tamu Massif is still controversial because evidence point to different formation hypotheses. In this paper, we applied the P-wave coda autocorrelation method and used the hydrophone waveform data acquired by the ocean bottom seismometer (OBS) deployed on Tamu Massif to constrain the oceanic crust, and these results provide new finding on the structure of the oceanic crust for Tamu Massif. We hope it can provide some implications to research the formation mechanism of Tamu Massif. These results show that some stations in Tamu Massif received reflection signals from shallower depths that are nearly parallel to the seafloor. We infer that in the shallow oceanic crust, there is a layer composed of alternating eruptions of dense, higher velocity massive lava and sparse, lower velocity pillow lava flows, which have less density and lower velocity compared to the lower oceanic crust, with a strong acoustic impedance contrasts between them and thus able to generate a reflection signal, which is observed in our autocorrelation results.},
	issn = {2296-6463},
	url = {https://www.frontiersin.org/articles/10.3389/feart.2023.1218576},
	author = {Xu, Fucong and Lu, Shaoping and Cai, Chen and Chen, Han and Dong, Shaozhe}
}
@article {trehu_deformation_2023,
	title = {Deformation of the Juan de Fuca Plate Beneath the Central Cascadia Continental Margin (44{\textdegree}-45{\textdegree}N) in Response to an Upper Plate Load},
	journal = {Earth Science, Systems and Society},
	volume = {3},
	year = {2023},
	note = {Publisher: Frontiers},
	month = {11/2023},
	pages = {10085},
	abstract = {A 3D crustal model for the central Cascadia continental shelf and Coast Range between 44{\textdegree}N and 45{\textdegree}N shows that the crystalline crust of the forearc wedge beneath the coastline is characterized by a NW-trending, vertical slab of high-velocity rock interpreted to represent the dike complex that fed the Yachats basaltsBasalt, which werewas intruded into the forearc approximately 3637 million years ago. A spatial correlation is observed between downward deflection of the crust of the subducting Juan de Fuca plate, inferred from inversion of PmP arrivals to image the Moho surface, and the high velocity (and consequently high density) dike complex.anomaly underlying the Yachats Basalt. Apparent subsequent rebound of the subducting plate at greater depth suggests a primarily elastic response of the subducting plate to this load. Calculations for a range of plausible values for the magnitude of the load and the width and depth of the depression indicate that that the effective elastic thickness of the subducted Juan de Fuca plate is \textasciitilde2-<6 km. Although our simple analytical models do not include partial support of the load of the slab by the adjacent upper plate crust or time dependence to account for the motion of the slab beneath the load, incorporation of those effects should decrease rather than increase the apparent strength of the subducted plate. We conclude that the subducted Juan de Fuca plate beneath the central Oregon margin is elastically thin and has the potential to store elastic strain energy before rupturing. Our model of a well-defined, focused and static upper plate load that locally deforms the subducted plate within the nominally seismogenic or transitional part of the Cascadia plate boundary may be unique in providing a relatively straightforward scenario for estimating the mechanical properties of the subducted Juan de Fuca plate. We extrapolate from these results to speculate that elastic deformation of the subducting plate may contribute to the low level of seismicity throughout much of the Cascadia forearc in inter-seismic period between great earthquakes but note that our local results do not preclude faulting or elasto-plastic deformation of a thin and weak plate as it subducts.},
	issn = {2634-730X},
	doi = {10.3389/esss.2023.10085},
	url = {https://www.escubed.org/articles/10.3389/esss.2023.10085/full},
	author = {Tr{\'e}hu, Anne M. and Davenport, Kathy and Kenyon, Christopher B. and Carbotte, Suzanne M. and N{\'a}b{\v e}lek, John L. and Toomey, Douglas R. and Wilcock, William S. D.}
}
@article {cheng_efficient_2023,
	title = {An Efficient Transfer Learning-Based OBS Seismic Phase Picker (OBSPD) Trained on Cascadia Subduction Zone Earthquake Dataset},
	journal = {Seismological Research Letters},
	volume = {95},
	number = {2A},
	year = {2023},
	month = {11/2024},
	pages = {834{\textendash}847},
	abstract = {Earthquake monitoring and many seismological studies depend on seismic phase arrivals. Thus, detecting seismic events and picking the phase arrival times are fundamentally important. In the recent years, seismic phase picking models based on deep learning approaches have been widely developed. These deep learning models can achieve better performances than traditional phase picking methods and improve the quality of phase picking for land-based earthquake monitoring. However, these models might not perform well on data from ocean-bottom seismometers (OBSs), because they are trained exclusively using onshore seismic data and have limited out-of-distribution generalization ability. Nevertheless, there are insufficient labeled OBS phase arrivals dataset to train a deep learning model from scratch. In this study, we developed an automatic phase detection model for OBS data (OBS phase detection [OBSPD]) using the transfer learning approach based on an existing U-GPD model with pretrained weights from a generalized phase detection model feature extraction system. We developed OBSPD with a limited amount of training data (2784 three-component event waveforms) from the Cascadia subduction zone (CSZ) OBS deployments. Our results show that transfer learning can achieve lower model loss with less overfitting compared to when training a model from scratch. Our new OBSPD model outperforms four existing deep learning pickers in terms of phase detection accuracy with smaller arrival time residuals on a test OBS dataset at CSZ, especially for P phases.},
	issn = {0895-0695},
	doi = {10.1785/0220230161},
	url = {https://doi.org/10.1785/0220230161},
	author = {Cheng, Zhangbao and Tan, Yen Joe and Zhang, Fan and Zhou, Pengcheng and Lin, Jian and Tian, Jinyu and Zhang, Xubo and Zha, Caicai}
}
@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 {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 {yang_optimal_2023,
	title = {Optimal stacking of noise cross-correlation functions},
	journal = {Geophysical Journal International},
	volume = {232},
	number = {3},
	year = {2023},
	month = {mar},
	pages = {1600{\textendash}1618},
	abstract = {Cross-correlations of ambient seismic noise are widely used for seismic velocity imaging, monitoring and ground motion analyses. A typical step in analysing noise cross-correlation functions (NCFs) is stacking short-term NCFs over longer time periods to increase the signal quality. Spurious NCFs could contaminate the stack, degrade its quality and limit its use. Many methods have been developed to improve the stacking of coherent waveforms, including earthquake waveforms, receiver functions and NCFs. This study systematically evaluates and compares the performance of eight stacking methods, including arithmetic mean or linear stacking, robust stacking, selective stacking, cluster stacking, phase-weighted stacking, time{\textendash}frequency phase-weighted stacking, Nth-root stacking and averaging after applying an adaptive covariance filter. Our results demonstrate that, in most cases, all methods can retrieve clear ballistic or first arrivals. However, they yield significant differences in preserving the phase and amplitude information. This study provides a practical guide for choosing the optimal stacking method for specific research applications in ambient noise seismology. We evaluate the performance using multiple onshore and offshore seismic arrays in the Pacific Northwest region. We compare these stacking methods for NCFs calculated from raw ambient noise (referred to as Raw NCFs) and from ambient noise normalized using a one-bit clipping time normalization method (referred to as One-bit NCFs). We evaluate six metrics, including signal-to-noise ratios, phase dispersion images, convergence rate, temporal changes in the ballistic and coda waves, relative amplitude decays with distance and computational time. We show that robust stacking is the best choice for all applications (velocity tomography, monitoring and attenuation studies) using Raw NCFs. For applications using One-bit NCFs, all methods but phase-weighted and Nth-root stacking are good choices for seismic velocity tomography. Linear, robust and selective stacking methods are all equally appropriate choices when using One-bit NCFs for monitoring applications. For applications relying on accurate relative amplitudes, the linear, robust, selective and cluster stacking methods all perform well with One-bit NCFs. The evaluations in this study can be generalized to a broad range of time-series analysis that utilizes data coherence to perform ensemble stacking. Another contribution of this study is the accompanying open-source software package, StackMaster, which can be used for general purposes of time-series stacking.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggac410},
	url = {https://doi.org/10.1093/gji/ggac410},
	author = {Yang, Xiaotao and Bryan, Jared and Okubo, Kurama and Jiang, Chengxin and Clements, Timothy and Denolle, Marine A}
}
@article {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 {paulatto_advances_2022,
	title = {Advances in seismic imaging of magma and crystal mush},
	journal = {Frontiers in Earth Science},
	volume = {10},
	year = {2022},
	month = {10/2022},
	abstract = {Seismic imaging methods have provided detailed three-dimensional constraints on the physical properties of magmatic systems leading to invaluable insight into the storage, differentiation and dynamics of magma. These constraints have been crucial to the development of our modern understanding of magmatic systems. However, there are still outstanding knowledge gaps resulting from the challenges inherent in seismic imaging of volcanoes. These challenges stem from the complex physics of wave propagation across highly heterogeneous low-velocity anomalies associated with magma reservoirs. Ray-based seismic imaging methods such as travel-time and surface-wave tomography lead to under-recovery of such velocity anomalies and to under-estimation of melt fractions. This review aims to help the volcanologist to fully utilize the insights gained from seismic imaging and account for the resolution limits. We summarize the advantages and limitations of the most common imaging methods and propose best practices for their implementation and the quantitative interpretation of low-velocity anomalies. We constructed and analysed a database of 277 seismic imaging studies at 78 arc, hotspot and continental rift volcanoes. Each study is accompanied by information about the seismic source, part of the wavefield used, imaging method, any detected low-velocity zones, and estimated melt fraction. Thirty nine studies attempted to estimate melt fractions at 22 different volcanoes. Only five studies have found evidence of melt storage at melt fractions above the critical porosity that separates crystal mush from mobile magma. The median reported melt fraction is 13\% suggesting that magma storage is dominated by low-melt fraction crystal mush. However, due to the limits of seismic resolution, the seismological evidence does not rule out the presence of small (<10~km3) and medium-sized (<100~km3) high-melt fraction magma chambers at many of the studied volcanoes. The combination of multiple tomographic imaging methods and the wider adoption of methods that use more of the seismic wavefield than the first arriving travel-times, promise to overcome some of the limitations of seismic tomography and provide more reliable constraints on melt fractions. Wider adoption of these new methods and advances in data collection are needed to enable a revolution in imaging magma reservoirs.},
	issn = {2296-6463},
	doi = {10.3389/feart.2022.970131},
	url = {https://www.frontiersin.org/articles/10.3389/feart.2022.970131},
	author = {Paulatto, Michele and Hooft, Emilie E. E. and Chrapkiewicz, Kajetan and Heath, Benjamin and Toomey, Douglas R. and Morgan, Joanna V.}
}
@article {janiszewski_broad-band_2023,
	title = {Broad-band ocean bottom seismometer noise properties},
	journal = {Geophysical Journal International},
	volume = {233},
	number = {1},
	year = {2022},
	month = {11/2022},
	pages = {297{\textendash}315},
	abstract = {We present a new compilation and analysis of broad-band ocean bottom seismometer noise properties from 15 yr of seismic deployments. We compile a comprehensive data set of representative four-component (seismometer and pressure gauge) noise spectra and cross-spectral properties (coherence, phase and admittance) for 551 unique stations spanning 18 U.S.-led experiments. This is matched with a comprehensive compilation of metadata parameters related to instrumentation and environmental properties for each station. We systematically investigate the similarity of noise spectra by grouping them according to these metadata parameters to determine which factors are the most important in determining noise characteristics. We find evidence for improvements in similarity of noise properties when grouped across parameters, with groupings by seismometer type and deployment water depth yielding the most significant and interpretable results. Instrument design, that is the entire deployed package, also plays an important role, although it strongly covaries with seismometer and water depth. We assess the presence of traditional sources of tilt, compliance, and microseismic noise to characterize their relative role across a variety of commonly used seismic frequency bands. We find that the presence of tilt noise is primarily dependent on the type of seismometer used (covariant with a particular subset of instrument design), that compliance noise follows anticipated relationships with water depth, and that shallow, oceanic shelf environments have systematically different microseism noise properties (which are, in turn, different from instruments deployed in shallow lake environments). These observations have important implications for the viability of commonly used seismic analysis techniques. Finally, we compare spectra and coherences before and after vertical channel tilt and compliance noise removal to evaluate the efficacy and limitations of these now standard processing techniques. These findings may assist in future experiment planning and instrument development, and our newly compiled noise data set serves as a building block for more targeted future investigations by the marine seismology community.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggac450},
	url = {https://doi.org/10.1093/gji/ggac450},
	author = {Janiszewski, Helen A and Eilon, Z and Russell, J B and Brunsvik, B and Gaherty, J B and Mosher, S G and Hawley, W B and Coats, S}
}
@article {acquisto_evidence_2022,
	title = {Evidence of Strong Upper Oceanic Crustal Hydration Outboard the Alaskan and Sumatran Subduction Zones},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {127},
	number = {10},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2022JB024751},
	pages = {e2022JB024751},
	abstract = {The hydration state of subducting oceanic crust has been proposed to influence subduction zone processes like seismic coupling at the megathrust interface and arc magmatism downdip. Plate bending in the outer rise region is thought to help rehydrate the incoming oceanic lithosphere before subduction. Although numerous seismic refraction studies provide constraints on the amount of water stored in the lower crust and uppermost mantle, little information exists about how much free water is present in the upper 1{\textendash}2 km of oceanic crust. Here, we present results from the application of advanced techniques to long-offset multi-channel seismic data acquired outboard the Alaskan and South Sumatran subduction zones. Our results show that the incoming upper crustal seismic layer, layer 2A, is significantly hydrated in both areas. Favorable conditions offshore the Alaska Peninsula promote the creation of a dense system of bending-related faults, facilitating the infiltration of fluids that increases average water estimates to \~{}3.9 wt.\% H2O in the outer rise. As the crust subducts and temperature increases, some free water may react with the host rocks to form mineral-bound water that is carried to greater depths, in agreement with elevated water contents found in arc lavas of Shumagin Gap volcanoes. Offshore Sumatra, we propose that similar layer 2A water estimates (\~{}3.2 wt.\% H2O average) and heterogeneous hydration within 2B are associated with the ongoing, slow, complex deformation occurring in the Wharton Basin and thus potentially contribute to the presence of a long-lived slow slip event recently inferred there at seismogenic depths.},
	keywords = {Alaska, hydration, subduction zone, Sumatra, upper crust},
	issn = {2169-9356},
	doi = {10.1029/2022JB024751},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JB024751},
	author = {Acquisto, Tanner and B{\'e}cel, Anne and Singh, Satish C. and Carton, H{\'e}l{\`e}ne}
}
@article {wei_improved_2022,
	title = {An Improved Earthquake Catalog During the 2018 K{\i}̄lauea Eruption From Combined Onshore and Offshore Seismic Arrays},
	journal = {Earth and Space Science},
	volume = {9},
	number = {6},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2021EA001979},
	month = {06/2022},
	pages = {e2021EA001979},
	abstract = {The Island of Hawai{\textquoteright}i was formed by repeated eruptions of basalts at an oceanic hotspot. K{\i}̄lauea, the youngest among the subaerial volcanoes of the island, erupted intensely in 2018. The eruption provided an opportunity to look into the mechanisms that operate at the volcano and associated earthquake activities, as it was recorded simultaneously, for the first time, by onshore and offshore seismometers. We used most of the publicly available seismic data during the eruption period, including temporary arrays, to build a more complete earthquake catalog during the eruption than that provided by the Hawaiian Volcano Observatory. We used a short-time-average/long-time-average method to identify potential earthquakes. The detections were associated with events and automatically picked with P-wave and S-wave arrivals, which were used to locate the events in a three-dimensional velocity model. After re-examining these earthquake events, their coda/duration magnitudes were determined. The resulting half-year catalog contains 375,736 events with one of the highest daily earthquake numbers ever reported (6,128 on 21 June 2018). A great number of events were recorded during the caldera collapses, from its beginning until its rapid ending. The catalog also contains abundant events near the Pu{\textquoteright}u{\textquoteleft}o{\textquoteleft}o vent and in the lower East Rift Zone, where an increase of seismicity in mid-July and August indicated a step-up in magma intrusion after the eruption.},
	keywords = {eruption, K{\i}̄lauea, offshore, onshore, seismicity},
	issn = {2333-5084},
	doi = {10.1029/2021EA001979},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021EA001979},
	author = {Wei, XiaoZhuo and Shen, Yang and Caplan-Auerbach, Jacqueline and Morgan, Julia K.}
}
@article {carchedi_investigating_2022,
	title = {Investigating Short-Period Lake-Generated Microseisms Using a Broadband Array of Onshore and Lake-Bottom Seismometers},
	journal = {Seismological Research Letters},
	volume = {93},
	number = {3},
	year = {2022},
	month = {02/2022},
	pages = {1585{\textendash}1600},
	abstract = {Recent analyses of ambient seismic noise proximal to large lakes identify excitations between periods of 0.5 and 5~s as lake-generated microseisms, though the mechanisms producing them remain unclear in the absence of distinct spectral peaks. We present a unique data set combining onshore and offshore seismometers to investigate the dominant parameters controlling water-to-solid-earth seismic coupling in a lacustrine environment. Using a set of broadband observations that include six lake-bottom seismometers, we compare signals collected both within and around Lake Malawi (Nyasa) in southeastern Africa, the fifth largest freshwater lake in the world. We document clear evidence for two peaks within the lake microseism band, with pervasive diurnal excitations between periods of \~{}0.6{\textendash}1.3 and \~{}1.3{\textendash}3~s. Variations in spectral behavior as a function of recording depth and proximity to both steep lake-floor slopes and the shoreline suggest that the spectral bands may correspond to single- and double-frequency generation processes, akin to primary and secondary ocean microseisms generated by the shoaling of wind-driven gravity waves along shorelines and wave interactions within the open body of water, respectively. However, both the absolute amplitudes and temporal evolution we observe in these two bands are complex and often inconsistent with traditional microseism theory. Therefore, these spectral bands may alternatively result from complex wave{\textendash}wave interaction at the lake surface within the enclosed northern end of the lake. The diurnal behavior of lake microseisms, as well as their polarizations, suggest that the wave energy is driven by a combination of seasonally varying nighttime winds funneled by lakeshore topography and waveguide effects. This work also provides a glimpse into seasonal variation in lacustrine ambient seismic noise and thus also into lake processes.},
	issn = {0895-0695},
	doi = {10.1785/0220210155},
	url = {https://doi.org/10.1785/0220210155},
	author = {Carchedi, Christopher James William and Gaherty, James B. and Webb, Spahr C. and Shillington, Donna J.}
}
@article {chrapkiewicz_magma_2022,
	title = {Magma Chamber Detected Beneath an Arc Volcano With Full-Waveform Inversion of Active-Source Seismic Data},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {23},
	number = {11},
	year = {2022},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022GC010475},
	month = {10/2022},
	pages = {e2022GC010475},
	abstract = {Arc volcanoes are underlain by complex systems of molten-rock reservoirs ranging from melt-poor mush zones to melt-rich magma chambers. Petrological and satellite data indicate that eruptible magma chambers form in the topmost few kilometres of the crust. However, very few chambers have ever been definitively located, suggesting that most are too short-lived or too small to be imaged, which has direct implications for hazard assessment and modeling of magma differentiation. Here we use a high-resolution technology based on inverting full seismic waveforms to image a small, high-melt-fraction magma chamber that was not detected with standard seismic tomography. The melt reservoir extends from \~{}2 to at least 4 km below sea level (b.s.l.) at Kolumbo{\textemdash}a submarine volcano near Santorini, Greece. The chamber coincides with the termination point of the recent earthquake swarms and may be a missing link between a deeper melt reservoir and the high-temperature hydrothermal system venting at the crater floor. The chamber poses a serious hazard as it could produce a highly explosive, tsunamigenic eruption in the near future. Our results suggest that similar reservoirs (relatively small but high-melt-fraction) may have gone undetected at other active volcanoes, challenging the existing eruption forecasts and reactive-flow models of magma differentiation.},
	keywords = {full-waveform inversion, Kolumbo volcano, magma chamber, magmatic system, Santorini volcanic field, volcano tomography},
	issn = {1525-2027},
	doi = {10.1029/2022GC010475},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022GC010475},
	author = {Chrapkiewicz, K. and Paulatto, M. and Heath, B. A. and Hooft, E. E. E. and Nomikou, P. and Papazachos, C. B. and Schmid, F. and Toomey, D. R. and Warner, M. R. and Morgan, J. V.}
}
@article {jezequel_pile_2022,
	title = {Pile driving repeatedly impacts the giant scallop (Placopecten magellanicus)},
	journal = {Scientific Reports},
	volume = {12},
	number = {1},
	year = {2022},
	month = {09/2022},
	pages = {15380},
	abstract = {Large-scale offshore wind farms are a critical component of the worldwide climate strategy. However, their developments have been opposed by the fishing industry because of concerns regarding the impacts of pile driving vibrations during constructions on commercially important marine invertebrates, including bivalves. Using field-based daily exposure, we showed that pile driving induced repeated valve closures in different scallop life stages, with particularly stronger effects for juveniles. Scallops showed no acclimatization to repetitive pile driving across and within days, yet quickly returned to their initial behavioral baselines after vibration-cessation. While vibration sensitivity was consistent, daily pile driving did not disrupt scallop circadian rhythm, but suggests serious impacts at night when valve openings are greater. Overall, our results show distance and temporal patterns can support future mitigation strategies but also highlight concerns regarding the larger impact ranges of impending widespread offshore wind farm constructions on scallop populations.},
	keywords = {Behavioural ecology, Climate-change ecology, Ecology},
	doi = {10.1038/s41598-022-19838-6},
	url = {https://app.dimensions.ai/details/publication/pub.1150956514},
	author = {J{\'e}z{\'e}quel, Youenn and Cones, Seth and Jensen, Frants H. and Brewer, Hannah and Collins, John and Mooney, T. Aran}
}
@article {christeson_seismic_2022,
	title = {Seismic evidence for magmatic underplating along the Kodiak-Bowie Seamount Chain, Gulf of Alaska},
	journal = {Tectonophysics},
	volume = {845},
	year = {2022},
	month = {11/2022},
	pages = {229639},
	abstract = {Oceanic crust formed at mid-ocean ridges may be later modified by off-ridge magmatism forming seamounts, guyots, and islands. We investigate processes associated with seamount formation in the Gulf of Alaska Seamount Province using two coincident seismic reflection/wide-angle profiles. A north-south profile crosses the Kodiak-Bowie Seamount Chain and Aja fracture zone (FZ), and an orthogonal east-west profile is located about 90~km south of the seamount chain over Pacific plate oceanic crust. Structure along the profile away from the seamount chain is consistent with typical oceanic crust. Crust in our study region is thinnest (about 5.6~km) at the Aja FZ. Unlike observations from active transform faults, no low-velocity anomaly is observed at the Aja FZ suggesting that the crustal velocities have recovered to normal values through crack closure and crack healing. Higher lower crustal velocities (\~{}7.3 and~>~7.5~km/s) and thicker crust (\~{}8.5 and~\~{}7.0~km) are observed near the Pratt and Durgin Seamounts and at the intersection of the Kodiak-Bowie Seamount Chain linear trend, respectively. These observations are attributed to magmatic underplating associated with seamount province magmatism. Lithospheric thickness variations across the Aja FZ may form a barrier or impediment to magmatic flow. The thickest crust (8.5~km) along our two profiles is located on the younger side of the FZ, and we suggest that the majority of magmatism jumped south of the Aja FZ when thinner lithosphere was encountered by the Bowie hot spot. The crustal structure near the Kodiak-Bowie Seamount Chain is most similar to that of other seamounts and guyots that formed on similarly young lithosphere (8{\textendash}12~Ma). Our results suggest that lithospheric thickness at the time of hot spot interaction has a large control on magmatic underplating at seamounts and seamount provinces.},
	keywords = {Fracture zone, Magmatic underplating, Seamount},
	issn = {0040-1951},
	doi = {10.1016/j.tecto.2022.229639},
	url = {https://www.sciencedirect.com/science/article/pii/S0040195122004334},
	author = {Christeson, Gail L. and Gulick, Sean P. S. and Walton, Maureen A. L. and Barth, Ginger A.}
}
@article {russell_seismological_2022,
	title = {Seismological Evidence for Girdled Olivine Lattice-Preferred Orientation in Oceanic Lithosphere and Implications for Mantle Deformation Processes During Seafloor Spreading},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {23},
	number = {10},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2022GC010542},
	pages = {e2022GC010542},
	abstract = {Seismic anisotropy produced by aligned olivine in oceanic lithosphere offers a window into mid-ocean ridge (MOR) dynamics. Yet, interpreting anisotropy in the context of grain-scale deformation processes and strain observed in laboratory experiments and natural olivine samples has proven challenging due to incomplete seismological constraints and length scale differences spanning orders of magnitude. To bridge this observational gap, we estimate an in situ elastic tensor for oceanic lithosphere using co-located compressional- and shear-wavespeed anisotropy observations at the NoMelt experiment located on \~{}70 Ma seafloor. The elastic model for the upper 7 km of the mantle, NoMelt_SPani7, is characterized by a fast azimuth parallel to the fossil-spreading direction, consistent with corner-flow deformation fabric. We compare this model with a database of 123 petrofabrics from the literature to infer olivine crystallographic orientations and shear strain accumulated within the lithosphere. Direct comparison to olivine deformation experiments indicates strain accumulation of 250\%{\textendash}400\% in the shallow mantle. We find evidence for D-type olivine lattice-preferred orientation (LPO) with fast [100] parallel to the shear direction and girdled [010] and [001] crystallographic axes perpendicular to shear. D-type LPO implies similar amounts of slip on the (010)[100] and (001)[100] easy slip systems during MOR spreading; we hypothesize that grain-boundary sliding during dislocation creep relaxes strain compatibility, allowing D-type LPO to develop in the shallow lithosphere. Deformation dominated by dislocation-accommodated grain-boundary sliding (disGBS) has implications for in situ stress and grain size during MOR spreading and implies grain-size dependent deformation, in contrast to pure dislocation creep.},
	keywords = {grain-boundary sliding, mid-ocean ridge, oceanic lithosphere, seafloor spreading, seismic anisotropy, surface waves},
	issn = {1525-2027},
	doi = {10.1029/2022GC010542},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022GC010542},
	author = {Russell, J. B. and Gaherty, J. B. and Mark, H. F. and Hirth, G. and Hansen, L. N. and Lizarralde, D. and Collins, J. A. and Evans, R. L.}
}
@article {boulahanis_structure_2022,
	title = {Structure and Evolution of Northern Juan de Fuca Crust and Uppermost Mantle Over the Last 8 Ma From an Active-Source Seismic Tomography Study},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {127},
	number = {9},
	year = {2022},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022JB023987},
	month = {08/2022},
	pages = {e2022JB023987},
	abstract = {We present results from a two-dimensional wide-angle controlled source seismic transect designed to characterize the velocity structure of the oceanic crust and uppermost mantle spanning the northern Juan de Fuca (JdF) plate from near Endeavor ridge to the Cascadia margin. Reflection and refraction travel time inversion is used to derive a tomographic Vp model of sediments, crust, and upper mantle. Velocity model results are compared to baseline reference Vp values for unaltered crustal and upper mantle rocks at temperatures assuming plate cooling. Effective medium theory is used to infer the degree of hydration of the crust and mantle. Results indicate a somewhat fractured and hydrated upper crust (<=2.5 wt\% water), a near dry lower crust (<=0.7 wt\%) and upper mantle (<=0.5 wt\%) west of the deformation front, and an \~{}75 km wide region of modestly lower velocity in the mid-plate. Comparison with prior results from a complementary transect offshore Oregon indicates significant differences in Vp of the upper crust, with lower Vp-inferred porosity along most of the Washington transects that may reflect different extents of fault-related alteration and sediment burial histories. Approaching the deformation front, Washington transect Vp structure indicates dryer conditions than offshore Oregon, consistent with differences in extent of subduction bend faulting found in reflection imaging studies. On both transects, quasi-abrupt changes in plate properties at ages of 8, 6, and 3.4/4 Ma are found. Distinct crustal accretion modes are recognized, aligning with changes in JdF plate motion and recent history of Cobb-Eickelberg hotspot influence on crustal accretion at the JdF ridge.},
	issn = {2169-9356},
	doi = {10.1029/2022JB023987},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JB023987},
	author = {Boulahanis, Bridgit and Carbotte, Suzanne M. and Canales, Juan Pablo and Han, Shuoshuo and Nedimovi{\'c}, Mladen R.}
}
@article {deng_theoretical_2022,
	title = {Theoretical Solution and Applications of Ocean Bottom Pressure Induced by Seismic Waves at High Frequencies},
	journal = {Geophysical Research Letters},
	volume = {49},
	number = {9},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2021GL096952},
	pages = {e2021GL096952},
	abstract = {Previous studies have demonstrated that the ocean-bottom pressure associated with seismic seafloor motion is linearly proportional to the vertical seafloor acceleration, for frequencies much lower than the resonance frequency of water layer (c0/4h, c0 water sound speed, h water depth). In this article, we use realistic observations to verify a theoretical relation between the ocean-bottom pressure and vertical acceleration up to the water resonance frequency. We then show two applications of the theoretical relation. First, the pressure amplitude recorded by differential pressure gauges is calibrated, and the calibration coefficient is found to vary by frequency. Second, Rayleigh wave phase velocity near the water resonance frequency can be calculated from recordings of pressure and vertical seafloor acceleration at a single station, which is useful to constrain the shallow Earth structure.},
	issn = {1944-8007},
	doi = {10.1029/2021GL096952},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021GL096952},
	author = {Deng, Han and An, Chao and Cai, Chen and Ren, Hengxin}
}
@article {harmon_tilt_2022,
	title = {Tilt Corrections for Normal Mode Observations on Ocean Bottom Seismic Data, an example from the PI-LAB experiment},
	journal = {Seismica},
	volume = {1},
	number = {1},
	year = {2022},
	note = {Number: 1},
	month = {11/2022},
	abstract = {Earth{\textquoteright}s normal modes are fundamental observations used in global seismic tomography to understand Earth structure. Land seismic station coverage is sufficient to constrain the broadest scale Earth structures. However, 70\% of Earth{\textquoteright}s surface is covered by the oceans, hampering our ability to observe variations in local mode frequencies that contribute to imaging small-scale structures. Broadband ocean bottom seismometers can record spheroidal modes to fill in gaps in global data coverage. Ocean bottom recordings are contaminated by signals from complex interactions between ocean and solid Earth dynamics at normal mode frequencies. We present a method for correcting tilt on broadband ocean bottom seismometers by rotation. The correction improves the ability of some instruments to observe spheroidal modes down to 0S4. We demonstrate this method using 15 broadband ocean bottom seismometers from the PI-LAB array. We measure normal mode peak frequency shifts and compare with 1-D reference mode frequencies and predictions from 3-D global models. Our measurements agree with the 3-D models for modes between 0S14 - 0S37 with small but significant differences. These differences likely reflect real Earth structure. This suggests incorporating ocean bottom normal mode measurements into global inversions will improve models of global seismic velocity structure.},
	keywords = {marine geophysics, normal modes, ocean bottom seismometer},
	issn = {2816-9387},
	doi = {10.26443/seismica.v1i1.196},
	url = {https://seismica.library.mcgill.ca/article/view/196},
	author = {Harmon, Nicholas and Laske, Gabi and Crawford, Wayne and Rychert, Catherine}
}
@article {cabieces_upper-lithospheric_2022,
	title = {Upper-lithospheric structure of northeastern Venezuela from joint inversion of surface-wave dispersion and receiver functions},
	journal = {Solid Earth},
	volume = {13},
	number = {11},
	year = {2022},
	note = {Publisher: Copernicus GmbH},
	month = {11/2022},
	pages = {1781{\textendash}1801},
	abstract = {We use 1.5 years of continuous recordings from an amphibious seismic network deployment in the region of northeastern South America and the southeastern Caribbean to study the crustal and uppermost mantle structure through a joint inversion of surface-wave dispersion curves determined from ambient seismic noise and receiver functions. The availability of both ocean bottom seismometers (OBSs) and land stations makes this experiment ideal to determine the best processing methods to extract reliable empirical Green{\textquoteright}s functions (EGFs) and construct a 3D shear velocity model. Results show EGFs with high signal-to-noise ratio for land{\textendash}land, land{\textendash}OBS and OBS{\textendash}OBS paths from a variety of stacking methods. Using the EGF estimates, we measure phase and group velocity dispersion curves for Rayleigh and Love waves. We complement these observations with receiver functions, which allow us to perform an H-k analysis to obtain Moho depth estimates across the study area. The measured dispersion curves and receiver functions are used in a Bayesian joint inversion to retrieve a series of 1D shear-wave velocity models, which are then interpolated to build a 3D model of the region. Our results display clear contrasts in the oceanic region across the border of the San Sebastian{\textendash}El Pilar strike-slip fault system as well as a high-velocity region that corresponds well with the continental craton of southeastern Venezuela. We resolve known geological features in our new model, including the Espino Graben and the Guiana Shield provinces, and provide new information about their crustal structures. Furthermore, we image the difference in the crust beneath the Matur{\'\i}n and Gu{\'a}rico sub-basins.},
	issn = {1869-9510},
	doi = {10.5194/se-13-1781-2022},
	url = {https://se.copernicus.org/articles/13/1781/2022/},
	author = {Cabieces, Roberto and Arnaiz-Rodr{\'\i}guez, Mariano S. and Villase{\~n}or, Antonio and Berg, Elizabeth and Olivar-Casta{\~n}o, Andr{\'e}s and Ventosa, Sergi and Ferreira, Ana M. G.}
}
@article {chaudhuri_widespread_2022,
	title = {Widespread Very Low Frequency Earthquakes (VLFEs) Activity Offshore Cascadia},
	journal = {Geophysical Research Letters},
	volume = {49},
	number = {13},
	year = {2022},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2022GL097962},
	pages = {e2022GL097962},
	abstract = {A significant amount of stress in the Cascadia subduction zone (CSZ) is released by different forms of slow earthquakes including tremors, low-frequency earthquakes, and very low-frequency earthquakes (VLFEs){\textemdash}all occurring onshore at the deeper part of the transition zone. Their activity offshore, however, remains elusive. We discover widespread occurrence of discrete VLFEs offshore Cascadia using ocean-bottom seismometers. Barring occasional regular fast earthquakes, VLFEs are the only seismic stress indicators offshore. Using centroid moment tensor inversion and matched filtering, we detect sequences of 12 distinct families of VLFEs. The VLFEs in northern CSZ have focal mechanisms consistent with the area{\textquoteright}s subduction zone deformation. Interestingly, the VLFEs in the southern part of CSZ show strike-slip faulting, attributed to offshore faults, sediment consolidation, subduction bending, and transpressional regimes created by complex plate tectonics. It challenges a canonical view of the seismogenic zone in Cascadia characterized by a frictionally homogeneous fault segment producing only regular fast earthquakes.},
	issn = {1944-8007},
	doi = {10.1029/2022GL097962},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022GL097962},
	author = {Chaudhuri, Kuntal and Ghosh, Abhijit}
}
@article {an_characteristics_2021,
	title = {Characteristics of Low-Frequency Horizontal Noise of Ocean-Bottom Seismic Data},
	journal = {Seismological Research Letters},
	volume = {93},
	number = {1},
	year = {2021},
	pages = {257{\textendash}267},
	abstract = {Horizontal records of ocean-bottom seismographs are usually noisy at low frequencies (\&lt; 0.1~Hz). The noise source is believed to be associated with ocean-bottom currents that may tilt the instrument. Currently horizontal records are mainly used to remove the coherent noise in vertical records, and there has been little literature that quantitatively discusses the mechanism and characteristics of low-frequency horizontal noise. In this article, we analyze in situ ocean-bottom measurements by rotating the data horizontally and evaluating the coherency between different channels. Results suggest that the horizontal noise consists of two components, random noise and principle noise whose direction barely changes in time. The amplitude and the direction of the latter are possibly related to the intensity and direction of ocean-bottom currents. Rotating the horizontal records to the direction of the principle noise can largely suppress the principle noise in the orthogonal horizontal channel. In addition, the horizontal noise is incoherent with pressure, indicating that the noise source is not ocean surface water waves (infragravity waves). At some stations in shallow waters (\&lt;300~m), horizontal noise around 0.07~Hz is found to be linearly proportional to the temporal derivative of pressure, which is explained by forces of added mass due to infragravity waves.},
	issn = {0895-0695},
	doi = {10.1785/0220200349},
	url = {https://doi.org/10.1785/0220200349},
	author = {An, Chao and Cai, Chen and Zhou, Lei and Yang, Ting}
}
@article {mark_constraints_2021,
	title = {Constraints on the Depth, Thickness, and Strength of the G Discontinuity in the Central Pacific From S Receiver Functions},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {126},
	number = {4},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2019JB019256},
	month = {03/2021},
	pages = {e2019JB019256},
	abstract = {The relative motion of the lithosphere with respect to the asthenosphere implies the existence of a boundary zone that accommodates shear between the rigid plates and flowing mantle. This shear zone is typically referred to as the lithosphere-asthenosphere boundary (LAB). The width of this zone and the mechanisms accommodating shear across it have important implications for coupling between mantle convection and surface plate motion. Seismic observations have provided evidence for several physical mechanisms that might help enable relative plate motion, but how these mechanisms each contribute to the overall accommodation of shear remains unclear. Here we present receiver function constraints on the discontinuity structure of the oceanic upper mantle at the NoMelt site in the central Pacific, where local constraints on shear velocity, anisotropy, conductivity, and attenuation down to \~{}300 km depth provide a comprehensive picture of upper mantle structure. We image a seismic discontinuity with a Vsv decrease of 4.5\% or more over a 0{\textendash}20 km thick gradient layer centered at a depth of \~{}65 km. We associate this feature with the Gutenberg discontinuity (G), and interpret our observation of G as resulting from strain localization across a dehydration boundary based on the good agreement between the discontinuity depth and that of the dry solidus. Transitions in Vsv, azimuthal anisotropy, conductivity, and attenuation observed at roughly similar depths suggest that the G discontinuity represents a region of localized strain within a broader zone accommodating shear between the lithosphere and asthenosphere.},
	issn = {2169-9356},
	doi = {10.1029/2019JB019256},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JB019256},
	author = {Mark, H. F. and Collins, J. A. and Lizarralde, D. and Hirth, G. and Gaherty, J. B. and Evans, R. L. and Behn, M. D.}
}
@article {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 {harmon_shear_2021,
	title = {Shear Velocity Inversion Guided by Resistivity Structure From the PI-LAB Experiment for Integrated Estimates of Partial Melt in the Mantle},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {126},
	number = {8},
	year = {2021},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2021JB022202},
	month = {08/2021},
	pages = {e2021JB022202},
	abstract = {The lithosphere-asthenosphere system is fundamental to our understanding of mantle convection and plate tectonics. The different sensitivities of seismic and electromagnetic methods can be used together to better constrain the properties of the system. Here, we re-examine the shear velocity model from Rayleigh waves in light of the magnetotelluric based resistivity models from the Passive Imaging of the Lithosphere Asthenosphere Boundary (PI-LAB) experiment near the equatorial Mid-Atlantic Ridge, with the goal of generating a structurally consistent velocity and resistivity model for the region. Cross-plots of the models suggest a linear or near-linear trend that is also in agreement with petrophysical predictions. We generate a new shear velocity model from the resistivity models based on petrophysical relationships. The new velocity model fits the phase velocity data, and the correlation coefficient between the shear velocity and resistivity models is increased. Much of the model can be predicted by expectations for a thermal half-space cooling model, although some regions require a combination of higher temperatures, volatiles, or partial melt. We use the petrophysical predictions to estimate the melt fraction, melt volatile content, and temperature structure of the asthenospheric anomalies. We find up to 4\% melt, with the lowest resistivities and shear velocities explained by up to 20\% water or 20\% CO2 in the melt or \~{}1\% nearly pure sulfide melt, depending on the set of assumptions used. Melt is required in punctuated anomalies over broad depth ranges, and also in channels at the base of the lithosphere. Melt in the asthenosphere is dynamic, yet persistent on geologic timescales.},
	keywords = {lithosphere asthenosphere, magnetotellurics, melt, Mid-Atlantic Ridge, Rayleigh wave tomography, small-scale convection},
	issn = {2169-9356},
	doi = {10.1029/2021JB022202},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021JB022202},
	author = {Harmon, Nicholas and Wang, Shunguo and Rychert, Catherine A. and Constable, Steven and Kendall, J. Michael}
}
@article {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 {miller_limited_2020,
	title = {Limited mantle hydration by bending faults at the Middle America Trench},
	journal = {Journal of Geophysical Research: Solid Earth},
	year = {2020},
	note = {Type: Journal Article},
	month = {12/2020},
	abstract = {Seismic anisotropy measurements show that upper mantle hydration at the Middle America Trench (MAT) is limited to serpentinization and/or water in fault zones, rather than distributed uniformly. Subduction of hydrated oceanic lithosphere recycles water back into the deep mantle, drives arc volcanism, and affects seismicity at subduction zones. Constraining the extent of upper mantle hydration is an important part of understanding many fundamental processes on Earth. Substantially reduced seismic velocities in tomography suggest that outer rise plate-bending faults provide a pathway for seawater to rehydrate the slab mantle just prior to subduction. Estimates of outer-rise hydration based on tomograms vary significantly, with some large enough to imply that, globally, subduction has consumed more than two oceans worth of water during the Phanerozoic. We found that, while the mean upper mantle wavespeed is reduced at the MAT outer rise, the amplitude and orientation of inherited anisotropy are preserved at depths >1 km below the Moho. At shallower depths, relict anisotropy is replaced by slowing in the fault-normal direction. These observations are incompatible with pervasive hydration but consistent with models of wave propagation through serpentinized fault zones that thin to <100-m in width at depths >1 km below Moho. Confining hydration to fault zones reduces water storage estimates for the MAT upper mantle from \~{}3.5 wt\% to <0.9 wt\% H20. Since the intermediate thermal structure in the \~{}24 Myr-old MAT slab favors serpentinization, limited hydration suggests that fault mechanics are the limiting factor, not temperatures. Subducting mantle may be similarly dry globally. This article is protected by copyright. All rights reserved. Upper mantle anisotropy indicates that hydration by fluid flow along bending faults is limited to fault zones that thin with depthConfining hydration to fault zones reduces estimates of water storage by an order of magnitudeA dry, intermediate-age slab mantle suggests that hydration may be globally limited by fault dynamics, rather than temperature Upper mantle anisotropy indicates that hydration by fluid flow along bending faults is limited to fault zones that thin with depth Confining hydration to fault zones reduces estimates of water storage by an order of magnitude A dry, intermediate-age slab mantle suggests that hydration may be globally limited by fault dynamics, rather than temperature.},
	keywords = {outer-rise hydration, upper mantle anisotropy, upper mantle hydration},
	doi = {10.1029/2020jb020982},
	url = {https://app.dimensions.ai/details/publication/pub.1133689698},
	author = {Miller, Nathaniel C. and Lizarralde, Daniel and Collins, John A. and Holbrook, W. Steven and Van Avendonk, H.}
}
@article {116,
	title = {Limited mantle hydration by bending faults at the Middle America Trench},
	journal = {Journal of Geophysical Research: Solid Earth},
	year = {2020},
	type = {Journal Article},
	abstract = {Seismic anisotropy measurements show that upper mantle hydration at the Middle America Trench (MAT) is limited to serpentinization and/or water in fault zones, rather than distributed uniformly. Subduction of hydrated oceanic lithosphere recycles water back into the deep mantle, drives arc volcanism, and affects seismicity at subduction zones. Constraining the extent of upper mantle hydration is an important part of understanding many fundamental processes on Earth. Substantially reduced seismic velocities in tomography suggest that outer rise plate-bending faults provide a pathway for seawater to rehydrate the slab mantle just prior to subduction. Estimates of outer-rise hydration based on tomograms vary significantly, with some large enough to imply that, globally, subduction has consumed more than two oceans worth of water during the Phanerozoic. We found that, while the mean upper mantle wavespeed is reduced at the MAT outer rise, the amplitude and orientation of inherited anisotropy are preserved at depths >1 km below the Moho. At shallower depths, relict anisotropy is replaced by slowing in the fault-normal direction. These observations are incompatible with pervasive hydration but consistent with models of wave propagation through serpentinized fault zones that thin to <100-m in width at depths >1 km below Moho. Confining hydration to fault zones reduces water storage estimates for the MAT upper mantle from \~{}3.5 wt\% to <0.9 wt\% H20. Since the intermediate thermal structure in the \~{}24 Myr-old MAT slab favors serpentinization, limited hydration suggests that fault mechanics are the limiting factor, not temperatures. Subducting mantle may be similarly dry globally. This article is protected by copyright. All rights reserved. Upper mantle anisotropy indicates that hydration by fluid flow along bending faults is limited to fault zones that thin with depthConfining hydration to fault zones reduces estimates of water storage by an order of magnitudeA dry, intermediate-age slab mantle suggests that hydration may be globally limited by fault dynamics, rather than temperature Upper mantle anisotropy indicates that hydration by fluid flow along bending faults is limited to fault zones that thin with depth Confining hydration to fault zones reduces estimates of water storage by an order of magnitude A dry, intermediate-age slab mantle suggests that hydration may be globally limited by fault dynamics, rather than temperature.},
	doi = {10.1029/2020jb020982},
	url = {https://app.dimensions.ai/details/publication/pub.1133689698},
	author = {Miller, Nathaniel C. and Lizarralde, Daniel and Collins, John A. and Holbrook, W. Steven and Van Avendonk, H.}
}
@article {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 {eimer_seismicity_2020,
	title = {Seismicity of the Incoming Plate and Forearc Near the Mariana Trench Recorded by Ocean Bottom Seismographs},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {21},
	number = {4},
	year = {2020},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020GC008953},
	month = {04/2020},
	pages = {e2020GC008953},
	abstract = {Earthquakes near oceanic trenches are important for studying incoming plate bending and updip thrust zone seismogenesis, yet are poorly constrained using seismographs on land. We use an ocean bottom seismograph (OBS) deployment spanning both the incoming Pacific Plate and the forearc to study seismicity near the Mariana Trench. The yearlong deployment in 2012{\textendash}2013 consisted of 20 broadband OBSs and 5 suspended hydrophones, with an additional 59 short period OBSs and hydrophones recording for 1 month. We locate 1,692 earthquakes using a nonlinear method with a 3D velocity model constructed from active source profiles and surface wave tomography results. Events occurring seaward of the trench occur to depths of 35 km below the seafloor, and focal mechanisms of the larger events indicate normal faulting corresponding to plate bending. Significant seismicity emerges about 70 km seaward from the trench, and the seismicity rate increases continuously towards the trench, indicating that the largest bending deformation occurs near the trench axis. These plate-bending earthquakes occur along faults that facilitate the hydration of the subducting plate, and the lateral and depth distribution of earthquakes is consistent with low-velocity regions imaged in previous studies. The forearc is marked by a heterogeneous distribution of low magnitude (<5 Mw) thrust zone seismicity, possibly due to the rough incoming plate topography and/or serpentinization of the forearc. A sequence of thrust earthquakes occurs at depths 10 km below seafloor and within 20 km of the trench axis, demonstrating that the megathrust is seismically active nearly to the trench.},
	issn = {1525-2027},
	doi = {10.1029/2020GC008953},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020GC008953},
	author = {Eimer, Melody and Wiens, Douglas A. and Cai, Chen and Lizarralde, Daniel and Jasperson, Hope}
}
@article {114,
	title = {South Atlantic Transect: Variations in Oceanic Crustal Structure at 31{\textdegree}S},
	journal = {Geochemistry Geophysics Geosystems},
	volume = {21},
	year = {2020},
	type = {Journal Article},
	abstract = {We present an analysis of geophysical data acquired along a transect of 0{\textendash}62 Ma crust located on the western flank of the Mid-Atlantic Ridge at 31{\textdegree}S; all crust was formed at the same ridge segment. Crustal thickness, constrained by five wide-angle profiles, has mean values of 5.6 km at 6.6 and 15.2 Ma, 7.0 km at 30.6 Ma, 5.5 km at 49.2 Ma, and 3.6 km at 61.2 Ma. Crustal thickness is uniform along each ridge-parallel profile (standard deviations 0.1{\textendash}0.3 km), indicating uniform along-axis magmatic accretion over lateral distances of 40{\textendash}60 km. The crustal structure of 61.2 Ma crust is not only anomalously thin compared to the other profiles but also contains regions with a linear velocity gradient from seafloor to Moho, which suggests that intense fracturing may extend to the base of the thin crust. Abyssal hill root-mean-square heights in the study region are 57{\textendash}142 m and have an inverse correlation with spreading rate. These values are lower than the average root-mean-square height of 196 m elsewhere on the southern Mid-Atlantic Ridge and indicate relatively high mantle temperatures in our study area. Unsedimented or lightly sedimented basement highs are prevalent at all ages; we argue that bottom currents scour the high topography, transporting sediment into adjacent basement lows. All drillsites planned for International Ocean Discovery Program Expeditions 390 and 393 are within 1{\textendash}10 km of unsedimented or lightly sedimented basement highs, which should facilitate fluid flow and continued geochemical exchange between crust and seafloor.},
	doi = {10.1029/2020gc009017},
	url = {https://app.dimensions.ai/details/publication/pub.1128393051},
	author = {Christeson, G. L. and Reece, R. S. and Kardell, D. A. and Estep, J. D. and Fedotova, A. and Goff, J. A.}
}
@article {cooper_variable_2020,
	title = {Variable water input controls evolution of the Lesser Antilles volcanic arc},
	journal = {Nature},
	volume = {582},
	number = {7813},
	year = {2020},
	note = {Number: 7813 Publisher: Nature Publishing Group},
	month = {jun},
	pages = {525{\textendash}529},
	abstract = {Oceanic lithosphere carries volatiles, notably water, into the mantle through subduction at convergent plate boundaries. This subducted water exercises control on the production of magma, earthquakes, formation of continental crust and mineral resources. Identifying different potential fluid sources (sediments, crust and mantle lithosphere) and tracing fluids from their release to the surface has proved challenging1. Atlantic subduction zones are a valuable endmember when studying this deep water cycle because hydration in Atlantic lithosphere, produced by slow spreading, is expected to be highly non-uniform2. Here, as part of a multi-disciplinary project in the Lesser Antilles volcanic arc3, we studied boron trace element and isotopic fingerprints of melt inclusions. These reveal that serpentine{\textemdash}that is, hydrated mantle rather than crust or sediments{\textemdash}is a dominant supplier of subducted water to the central arc. This serpentine is most likely to reside in a set of major fracture zones subducted beneath the central arc over approximately the past ten million years. The current dehydration of these fracture zones coincides with the~current locations of the highest rates of earthquakes and prominent low shear velocities, whereas the preceding history~of~dehydration is consistent with the locations of~higher volcanic productivity and thicker arc crust. These combined geochemical and geophysical data indicate that the structure and hydration of the subducted plate are directly connected to the evolution of the arc and its associated seismic and volcanic hazards.},
	keywords = {Geochemistry, Geodynamics, Geophysics, seismology, Volcanology},
	issn = {1476-4687},
	doi = {10.1038/s41586-020-2407-5},
	url = {https://www.nature.com/articles/s41586-020-2407-5},
	author = {Cooper, George F. and Macpherson, Colin G. and Blundy, Jon D. and Maunder, Benjamin and Allen, Robert W. and Goes, Saskia and Collier, Jenny S. and Bie, Lidong and Harmon, Nicholas and Hicks, Stephen P. and Iveson, Alexander A. and Prytulak, Julie and Rietbrock, Andreas and Rychert, Catherine A. and Davidson, Jon P.}
}
@article {118,
	title = {Vp/Vs Ratio of Incoming Sediments Off Cascadia Subduction Zone From Analysis of Controlled-Source Multicomponent OBS Records},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {125},
	year = {2020},
	type = {Journal Article},
	abstract = {P-to-S-converted waves observed in controlled-source multicomponent ocean bottom seismometer (OBS) records were used to derive the Vp/Vs structure of Cascadia Basin sediments. We used P-to-S waves converted at the basement to derive an empirical function describing the average Vp/Vs of Cascadia sediments as a function of sediment thickness. We derived one-dimensional interval Vp/Vs functions from semblance velocity analysis of S-converted intrasediment and basement reflections, which we used to define an empirical Vp/Vs versus burial depth compaction trend. We find that seaward from the Cascadia deformation front, Vp/Vs structure offshore northern Oregon and Washington shows little variability along strike, while the structure of incoming sediments offshore central Oregon is more heterogeneous and includes intermediate-to-deep sediment layers of anomalously elevated Vp/Vs. These zones with elevated Vp/Vs are likely due to elevated pore fluid pressures, although layers of high sand content intercalated within a more clayey sedimentary sequence, and/or a higher content of coarser-grained clay minerals relative to finer-grained smectite could be contributing factors. We find that the proto-d{\'e}collement offshore central Oregon develops within the incoming sediments at a low-permeability boundary that traps fluids in a stratigraphic level where fluid overpressure exceeds 50\% of the differential pressure between the hydrostatic pressure and the lithostatic pressure. Incoming sediments with the highest estimated fluid overpressures occur offshore central Oregon where deformation of the accretionary prism is seaward vergent. Conversely, landward vergence offshore northern Oregon and Washington correlates with more moderate pore pressures and laterally homogeneous Vp/Vs functions of Cascadia Basin sediments. Average and interval Vp/Vs versus depth functions derived from S-converted waves from the Ridge-to-Trench seismic experiment in Cascadia Basin Layers with high Vp/Vs indicate elevated pore fluid pressure in incoming sediments Variations in Vp/Vs structure correlate with underthrust sediment thickness and wedge deformation style.},
	doi = {10.1029/2019jb019239},
	url = {https://app.dimensions.ai/details/publication/pub.1127957341},
	author = {Zhu, Jian and Canales, J. Pablo and Han, Shuoshuo and Carbotte, Suzanne M. and Arnulf, Adrien and Nedimovi{\'c}, Mladen R.}
}
@article {mark_azimuthal_2019,
	title = {Azimuthal Seismic Anisotropy of 70-Ma Pacific-Plate Upper Mantle},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {124},
	number = {2},
	year = {2019},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2018JB016451},
	month = {02/2019},
	pages = {1889{\textendash}1909},
	abstract = {Plate formation and evolution processes are predicted to generate upper mantle seismic anisotropy and negative vertical velocity gradients in oceanic lithosphere. However, predictions for upper mantle seismic velocity structure do not fully agree with the results of seismic experiments. The strength of anisotropy observed in the upper mantle varies widely. Further, many refraction studies observe a fast direction of anisotropy rotated several degrees with respect to the paleospreading direction, suggesting that upper mantle anisotropy records processes other than 2-D corner flow and plate-driven shear near mid-ocean ridges. We measure 6.0 {\textpm} 0.3\% anisotropy at the Moho in 70-Ma lithosphere in the central Pacific with a fast direction parallel to paleospreading, consistent with mineral alignment by 2-D mantle flow near a mid-ocean ridge. We also find an increase in the strength of anisotropy with depth, with vertical velocity gradients estimated at 0.02 km/s/km in the fast direction and 0 km/s/km in the slow direction. The increase in anisotropy with depth can be explained by mechanisms for producing anisotropy other than intrinsic effects from mineral fabric, such as aligned cracks or other structures. This measurement of seismic anisotropy and gradients reflects the effects of both plate formation and evolution processes on seismic velocity structure in mature oceanic lithosphere, and can serve as a reference for future studies to investigate the processes involved in lithospheric formation and evolution.},
	issn = {2169-9356},
	doi = {10.1029/2018JB016451},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JB016451},
	author = {Mark, H. F. and Lizarralde, D. and Collins, J. A. and Miller, N. C. and Hirth, G. and Gaherty, J. B. and Evans, R. L.}
}
@article {lynner_eastern_2019,
	title = {The Eastern North American Margin Community Seismic Experiment: An Amphibious Active- and Passive-Source Dataset},
	journal = {Seismological Research Letters},
	volume = {91},
	number = {1},
	year = {2019},
	month = {10/2019},
	pages = {533{\textendash}540},
	abstract = {The eastern North American margin community seismic experiment (ENAM-CSE) was conceived to target the ENAM Geodynamic Processes at Rifting and Subducting Margins (GeoPRISMS) primary site with a suite of both active- and passive-source seismic data that would shed light on the processes associated with rift initiation and evolution. To fully understand the ENAM, it was necessary to acquire a seismic dataset that was both amphibious, spanning the passive margin from the continental interior onto the oceanic portion of the North American plate, and multiresolution, enabling imaging of the sediments, crust, and mantle lithosphere. The ENAM-CSE datasets were collected on- and offshore of North Carolina and Virginia over a series of cruises and land-based deployments between April 2014 and June 2015. The passive-source component of the ENAM-CSE included 30 broadband ocean-bottom seismometers (OBSs) and 3 onshore broadband instruments. The broadband stations were deployed contemporaneously with those of the easternmost EarthScope Transportable Array creating a trans-margin amphibious seismic dataset. The active-source portion of the ENAM-CSE included several components: (1)~two onshore wide-angle seismic profiles where explosive shots were recorded on closely spaced geophones; (2)~four major offshore wide-angle seismic profiles acquired with an airgun source and short-period OBSs (SPOBSs), two of which were extended onland by deployments of short-period seismometers; (3)~marine multichannel seismic (MCS) data acquired along the four lines of SPOBSs and a series of other profiles along and across the margin. During the cruises, magnetic, gravity, and bathymetric data were also collected along all MCS profiles. All of the ENAM-CSE products were made publicly available shortly after acquisition, ensuring unfettered community access to this unique dataset.},
	issn = {0895-0695},
	doi = {10.1785/0220190142},
	url = {https://doi.org/10.1785/0220190142},
	author = {Lynner, Colton and J. A. Van Avendonk, Harm and B{\'e}cel, Anne and Christeson, Gail L. and Dugan, Brandon and Gaherty, James B. and Harder, Steven and Hornbach, Matthew J. and Lizarralde, Daniel and Long, Maureen D. and Magnani, M. Beatrice and Shillington, Donna J. and Aderhold, Kasey and Eilon, Zachary C. and Wagner, Lara S.}
}
@article {warren-smith_episodic_2019,
	title = {Episodic stress and fluid pressure cycling in subducting oceanic crust during slow slip},
	journal = {Nature Geoscience},
	volume = {12},
	number = {6},
	year = {2019},
	note = {Number: 6 Publisher: Nature Publishing Group},
	month = {jun},
	pages = {475{\textendash}481},
	abstract = {Slow slip events are part of a spectrum of aseismic processes that relieve tectonic stress on faults. Their spatial distribution in subduction zones has been linked to perturbations in fluid pressure within the megathrust shear zone and subducting oceanic crust. However, physical observations of temporal fluid pressure fluctuations through slow slip cycles remain elusive. Here, we use earthquake focal mechanisms recorded on an ocean-bottom seismic network to show that crustal stresses and fluid pressures within subducting oceanic crust evolve before and during slow slip events. Specifically, we observe that the retrieved stress ratio, which describes the relative magnitudes of the principal compressive stresses, systematically decreases before slow slip events in New Zealand{\textquoteright}s northern Hikurangi subduction zone, and subsequently increases during the evolution of each slow slip event. We propose that these changes represent the accumulation and release of fluid pressure within overpressured subducting oceanic crust, the episodicity of which may influence the timing of slow slip event occurrence on subduction megathrusts. This work contributes an improved understanding of the physical driving forces underlying slow subduction earthquakes, and a potential means by which to monitor stress and fluid pressure accumulation in such regions.},
	keywords = {seismology, Tectonics},
	issn = {1752-0908},
	doi = {10.1038/s41561-019-0367-x},
	url = {https://www.nature.com/articles/s41561-019-0367-x},
	author = {Warren-Smith, E. and Fry, B. and Wallace, L. and Chon, E. and Henrys, S. and Sheehan, A. and Mochizuki, K. and Schwartz, S. and Webb, S. and Lebedev, S.}
}
@article {Russell2019,
	title = {High-Resolution Constraints on Pacific Upper Mantle Petrofabric Inferred From Surface-Wave Anisotropy},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {124},
	number = {1},
	year = {2019},
	month = {jan},
	pages = {631{\textendash}657},
	issn = {2169-9313},
	doi = {10.1029/2018JB016598},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JB016598},
	author = {Russell, Joshua B. and Gaherty, James B. and Lin, Pei-Ying Patty and Lizarralde, Daniel and Collins, John A. and Hirth, Greg and Evans, Rob L.}
}
@article {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 {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 {merz_seismicity_2019,
	title = {Seismicity and Velocity Structure of Lo{\textquoteright}ihi Submarine Volcano and Southeastern Hawai{\textquoteright}i},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {124},
	number = {11},
	year = {2019},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2019JB018168},
	pages = {11380{\textendash}11393},
	abstract = {Hundreds of earthquakes were recorded during a nine-month ocean bottom seismometer deployment surrounding Lo{\textquoteright}ihi submarine volcano, Hawai{\textquoteright}i. The 12-station ocean bottom seismometer network widened the aperture of earthquake detection around the Big Island, allowing better constraints on the location of seismicity offshore Hawai{\textquoteright}i. Although this deployment occurred during a time of volcanic quiescence for Lo{\textquoteright}ihi, it establishes an important basis for background seismicity of the volcano. Offshore seismicity during this study was dominated by events located in the mantle fault zone at depths of 25{\textendash}40 km. These events reflect rupture on preexisting faults in the lower lithosphere caused by stresses induced by volcano loading and flexure of the Pacific Plate (Pritchard et al., 2007, https://doi.org/10.1111/j.1365-246X.2006.03169.x; Wolfe et al., 2004, https://doi.org/10.1029/2003GC000618). Tomography was performed using double-difference seismic tomography and showed shallow velocities to be slower than the regional velocity model (HG50; Klein, 1981, https://pubs.geoscienceworld.org/ssa/bssa/article/71/5/1503/118231/A-linear-gradient-crustal-model-for-south-Hawaii). A broad, low-velocity anomaly was observed from 20{\textendash}40-km depth, and is suggestive of the central plume conduit that supplies magma to Lo{\textquoteright}ihi and the active volcanoes of the Big Island. A localized high-velocity body is observed 4{\textendash}6-km depth beneath Lo{\textquoteright}ihi{\textquoteright}s summit, extending 10 km to the north and south. Following Lo{\textquoteright}ihi{\textquoteright}s active rift zones and crossing the summit, this high-velocity body is characteristic of intrusive material. Two low-velocity anomalies are observed below the oceanic crust, interpreted as melt accumulation beneath Lo{\textquoteright}ihi and magmatic underplating beneath Hawai{\textquoteright}i Island.},
	keywords = {Hawai{\textquoteright}i, hot spot, Lo{\textquoteright}ihi seamount, tomography, volcano seismology},
	issn = {2169-9356},
	doi = {10.1029/2019JB018168},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JB018168},
	author = {Merz, D. K. and Caplan-Auerbach, J. and Thurber, C. H.}
}
@article {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 {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 {moyer_spatial_2018,
	title = {Spatial and Temporal Variations in Earthquake Stress Drop on Gofar Transform Fault, East Pacific Rise: Implications for Fault Strength},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {123},
	number = {9},
	year = {2018},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2018JB015942},
	pages = {7722{\textendash}7740},
	abstract = {On Gofar Transform Fault on the East Pacific Rise, the largest earthquakes (6.0 <= MW <= 6.2) have repeatedly ruptured the same portion of the fault, while intervening fault segments host swarms of microearthquakes. These long-term patterns in earthquake occurrence suggest that heterogeneous fault zone properties control earthquake behavior. Using waveforms from ocean bottom seismometers that recorded seismicity before and after an anticipated 2008 MW 6.0 mainshock, we investigate the role that differences in material properties have on earthquake rupture at Gofar. We determine stress drop for 138 earthquakes (2.3 <= MW <= 4.0) that occurred within and between the rupture areas of large earthquakes. Stress drops are calculated from corner frequencies derived using an empirical Green{\textquoteright}s function spectral ratio method, and seismic moments are obtained by fitting the omega-square source model to the low frequency amplitude of the displacement spectrum. Our analysis yields stress drops from 0.04 to 3.2 MPa with statistically significant spatial variation, including 2 times higher average stress drop in fault segments where large earthquakes also occur compared to fault segments that host earthquake swarms. We find an inverse correlation between stress drop and P wave velocity reduction, which we interpret as the effect of fault zone damage on the ability of the fault to store strain energy that leads to our spatial variations in stress drop. Additionally, we observe lower stress drops following the MW 6.0 mainshock, consistent with increased damage and decreased fault strength after a large earthquake.},
	keywords = {earthquake stress drop, earthquake swarms, fault zone damage, oceanic transform faults, rupture dynamics, seismic coupling},
	issn = {2169-9356},
	doi = {10.1029/2018JB015942},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JB015942},
	author = {Moyer, Pamela A. and Boettcher, Margaret S. and McGuire, Jeffery J. and Collins, John A.}
}
@article {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 {Canales2017a,
	title = {Dry Juan de Fuca slab revealed by quantification of water entering Cascadia subduction zone},
	journal = {Nature Geoscience},
	volume = {10},
	number = {11},
	year = {2017},
	month = {nov},
	pages = {864{\textendash}870},
	issn = {1752-0894},
	doi = {10.1038/ngeo3050},
	url = {http://www.nature.com/articles/ngeo3050},
	author = {Canales, J. P. and Carbotte, S. M. and Nedimovi{\'c}, M. R. and Carton, H.}
}
@article {Cattania2017,
	title = {Dynamic triggering and earthquake swarms on East Pacific Rise transform faults},
	journal = {Geophysical Research Letters},
	volume = {44},
	number = {2},
	year = {2017},
	month = {jan},
	pages = {702{\textendash}710},
	issn = {0094-8276},
	doi = {10.1002/2016GL070857},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2016GL070857},
	author = {Cattania, Camilla and McGuire, Jeffrey J. and Collins, John A.}
}
@article {Flores2017,
	title = {Observations of Seismicity and Ground Motion in the Northeast U.S. Atlantic Margin from Ocean-Bottom Seismometer Data},
	journal = {Seismological Research Letters},
	volume = {88},
	number = {1},
	year = {2017},
	month = {jan},
	pages = {23{\textendash}31},
	issn = {0895-0695},
	doi = {10.1785/0220160079},
	url = {https://pubs.geoscienceworld.org/srl/article/88/1/23-31/314313},
	author = {Flores, Claudia H. and ten Brink, Uri S. and McGuire, Jeffrey J. and Collins, John A.}
}
@article {Canales2017,
	title = {Seismic imaging of magma sills beneath an ultramafic-hosted hydrothermal system},
	journal = {Geology},
	volume = {45},
	number = {5},
	year = {2017},
	month = {may},
	pages = {451{\textendash}454},
	issn = {0091-7613},
	doi = {10.1130/G38795.1},
	url = {https://pubs.geoscienceworld.org/geology/article/45/5/451-454/207914},
	author = {Canales, J. Pablo and Dunn, Robert A. and Arai, Ryuta and Sohn, Robert A.}
}
@article {Wei2017,
	title = {Slab temperature controls on the Tonga double seismic zone and slab mantle dehydration},
	journal = {Science Advances},
	volume = {3},
	number = {1},
	year = {2017},
	month = {jan},
	pages = {e1601755},
	issn = {2375-2548},
	doi = {10.1126/sciadv.1601755},
	url = {https://advances.sciencemag.org/lookup/doi/10.1126/sciadv.1601755},
	author = {Wei, S. Shawn and Wiens, Douglas A. and van Keken, Peter E. and Cai, Chen}
}
@article {Accardo2017,
	title = {Surface wave imaging of the weakly extended Malawi Rift from ambient-noise and teleseismic Rayleigh waves from onshore and lake-bottom seismometers},
	journal = {Geophysical Journal International},
	volume = {209},
	number = {3},
	year = {2017},
	month = {jun},
	pages = {1892{\textendash}1905},
	issn = {0956-540X},
	doi = {10.1093/gji/ggx133},
	url = {https://academic.oup.com/gji/article/209/3/1892/3098113},
	author = {Accardo, N.J. and Gaherty, J.B. and Shillington, D.J. and Ebinger, C.J. and Nyblade, A.A. and Mbogoni, G.J. and Chindandali, P.R.N. and Ferdinand, R.W. and Mulibo, G.D. and Kamihanda, G. and Keir, D. and Scholz, C. and Selway, K. and O{\textquoteright}Donnell, J.P. and Tepp, G. and Gallacher, R. and Mtelela, K. and Salima, J. and Mruma, A.}
}
@article {An2017,
	title = {Theoretical Solution and Applications of Ocean Bottom Pressure Induced by Seismic Seafloor Motion},
	journal = {Geophysical Research Letters},
	volume = {44},
	number = {20},
	year = {2017},
	month = {oct},
	pages = {10,272{\textendash}10,281},
	issn = {00948276},
	doi = {10.1002/2017GL075137},
	url = {http://doi.wiley.com/10.1002/2017GL075137},
	author = {An, Chao and Cai, Chen and Zheng, Yong and Meng, Lingsen and Liu, Philip}
}
@article {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 {Horning2016,
	title = {A 2-D tomographic model of the Juan de Fuca plate from accretion at axial seamount to subduction at the Cascadia margin from an active source ocean bottom seismometer survey},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {121},
	number = {8},
	year = {2016},
	month = {aug},
	pages = {5859{\textendash}5879},
	issn = {21699313},
	doi = {10.1002/2016JB013228},
	url = {http://doi.wiley.com/10.1002/2016JB013228},
	author = {Horning, G. and Canales, J. P. and Carbotte, S. M. and Han, S. and Carton, H. and Nedimovi{\'c}, M. R. and van Keken, P. E.}
}
@article {Shillington2016,
	title = {Acquisition of a Unique Onshore/Offshore Geophysical and Geochemical Dataset in the Northern Malawi (Nyasa) Rift},
	journal = {Seismological Research Letters},
	volume = {87},
	number = {6},
	year = {2016},
	month = {nov},
	pages = {1406{\textendash}1416},
	issn = {0895-0695},
	doi = {10.1785/0220160112},
	url = {https://pubs.geoscienceworld.org/srl/article/87/6/1406-1416/314187},
	author = {Shillington, Donna J. and Gaherty, James B. and Ebinger, Cynthia J. and Scholz, Christopher A. and Selway, Kate and Nyblade, Andrew A. and Bedrosian, Paul A. and Class, Cornelia and Nooner, Scott L. and Pritchard, Matthew E. and Elliott, Julie and Chindandali, Patrick R. N. and Mbogoni, Gaby and Ferdinand, Richard Wambura and Boniface, Nelson and Manya, Shukrani and Kamihanda, Godson and Saria, Elifuraha and Mulibo, Gabriel and Salima, Jalf and Mruma, Abdul and Kalindekafe, Leonard and Accardo, Natalie J. and Ntambila, Daud and Kachingwe, Marsella and Mesko, Gary T. and McCartney, Tannis and Maquay, Melania and O{\textquoteright}Donnell, J. P. and Tepp, Gabrielle and Mtelela, Khalfan and Trinhammer, Per and Wood, Douglas and Aaron, Ernest and Gibaud, Mark and Rapa, Martin and Pfeifer, Cathy and Mphepo, Felix and Gondwe, Duncan and Arroyo, Gabriella and Eddy, Celia and Kamoga, Brian and Moshi, Mary}
}
@article {st_clair_along-strike_2016,
	title = {Along-strike structure of the Costa Rican convergent margin from seismic a refraction/reflection survey: Evidence for underplating beneath the inner forearc},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {17},
	number = {2},
	year = {2016},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2015GC006029},
	month = {02/2016},
	pages = {501{\textendash}520},
	abstract = {The convergent margin offshore Costa Rica shows evidence of subsidence due to subduction erosion along the outer forearc and relatively high rates of uplift (\~{}3{\textendash}6 mm/yr) along the coast. Recently erupted arc lavas exhibit a low 10Be signal, suggesting that although nearly the entire package of incoming sediments enters the subduction zone, very little of that material is carried directly with the downgoing Cocos plate to the magma generating depths of the mantle wedge. One mechanism that would explain both the low 10Be and the coastal uplift is the underplating of sediments, tectonically eroded material, and seamounts beneath the inner forearc. We present results of a 320 km long, trench-parallel seismic reflection and refraction study of the Costa Rican forearc. The primary observations are (1) margin perpendicular faulting of the basement, (2) thickening of the Cocos plate to the northwest, and (3) two weak bands of reflections in the multichannel seismic (MCS) reflection image with travel times similar to the top of the subducting Cocos plate. The modeled depths to these reflections are consistent with an \~{}40 km long, 1{\textendash}3 km thick region of underplated material \~{}15 km beneath some of the highest observed coastal uplift rates in Costa Rica.},
	keywords = {convergent margin, Costa Rica, subduction zone processes},
	issn = {1525-2027},
	doi = {10.1002/2015GC006029},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2015GC006029},
	author = {St. Clair, J. and Holbrook, W. S. and Van Avendonk, H. J. A. and Lizarralde, D.}
}
@article {Lin2016,
	title = {High-resolution seismic constraints on flow dynamics in the oceanic asthenosphere},
	journal = {Nature},
	volume = {535},
	number = {7613},
	year = {2016},
	month = {jul},
	pages = {538{\textendash}541},
	issn = {0028-0836},
	doi = {10.1038/nature18012},
	url = {http://www.nature.com/articles/nature18012},
	author = {Lin, Pei-Ying Patty and Gaherty, James B. and Jin, Ge and Collins, John A. and Lizarralde, Daniel and Evans, Rob. L. and Hirth, Greg}
}
@article {Ball2016,
	title = {Lithospheric shear velocity structure of South Island, New Zealand, from amphibious Rayleigh wave tomography},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {121},
	number = {5},
	year = {2016},
	month = {may},
	pages = {3686{\textendash}3702},
	issn = {21699313},
	doi = {10.1002/2015JB012726},
	url = {http://doi.wiley.com/10.1002/2015JB012726},
	author = {Ball, Justin S. and Sheehan, Anne F. and Stachnik, Joshua C. and Lin, Fan-Chi and Yeck, William L. and Collins, John A.}
}
@article {Chen2016a,
	title = {Measuring earthquake source parameters in the Mendocino triple junction region using a dense OBS array: Implications for fault strength variations},
	journal = {Earth and Planetary Science Letters},
	volume = {453},
	year = {2016},
	month = {nov},
	pages = {276{\textendash}287},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2016.08.022},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X16304459},
	author = {Chen, Xiaowei and McGuire, Jeffrey J.}
}
@article {Chen2016,
	title = {Microseism source direction from noise cross-correlation},
	journal = {Geophysical Journal International},
	volume = {205},
	number = {2},
	year = {2016},
	month = {05/2016},
	pages = {810{\textendash}818},
	abstract = {Inhomogeneous noise sources surrounding stations produce asymmetric amplitudes in cross-correlation functions that yield preferential source directions. Here we show that preprocessing biases the dominant source direction estimate towards the source producing long-duration signals by down-weighting high-amplitude signals. Tests with both synthetic data and observations show that conventional preprocessing, where only earthquakes and local transients (e.g. trawling, fish impacts) are removed, is more sensitive to coherent energy, while one-bit preprocessing and running-absolute-mean preprocessing are more influenced by signal duration. Comparisons between different preprocessing methods are made on data from the Cascadia Initiative ocean bottom seismometer array, where we find that the total energy arriving from pelagic and coastal areas is similar. Moreover, pelagic-generated signals tend to be weaker but have longer duration, in contrast to coastal-generated signals that tend to be stronger but have shorter duration.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggw055},
	url = {https://academic.oup.com/gji/article-lookup/doi/10.1093/gji/ggw055},
	author = {Chen, Zhao and Gerstoft, Peter and Bromirski, Peter D.}
}
@conference {Gardner2016,
	title = {A second look at Chip Scale Atomic Clocks for long term precision timing},
	booktitle = {OCEANS 2016 MTS/IEEE Monterey},
	year = {2016},
	month = {sep},
	pages = {1{\textendash}9},
	publisher = {IEEE},
	organization = {IEEE},
	isbn = {978-1-5090-1537-5},
	doi = {10.1109/OCEANS.2016.7761268},
	url = {http://ieeexplore.ieee.org/document/7761268/},
	author = {Gardner, Alan T. and Collins, John A.}
}
@article {Chakravorty2016,
	title = {Small-scale factors influence mantle flow under the seafloor},
	journal = {Earth Magazine},
	volume = {November},
	year = {2016},
	url = {https://www.earthmagazine.org/article/small-scale-factors-influence-mantle-flow-under-seafloor/},
	author = {Chakravorty, A.}
}
@article {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 {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}
}
@inbook {Cheng2015,
	title = {Seismic Constraints on a Double-Layered Asymmetric Whole-Mantle Plume Beneath Hawai{\textquoteleft}i},
	year = {2015},
	month = {feb},
	pages = {19{\textendash}34},
	doi = {10.1002/9781118872079.ch2},
	url = {http://doi.wiley.com/10.1002/9781118872079.ch2},
	author = {Cheng, Cheng and Allen, Richard M. and Porritt, Rob W. and Ballmer, Maxim D.}
}
@article {Wei2015,
	title = {Seismic evidence of effects of water on melt transport in the Lau back-arc mantle},
	journal = {Nature},
	volume = {518},
	number = {7539},
	year = {2015},
	month = {feb},
	pages = {395{\textendash}398},
	issn = {0028-0836},
	doi = {10.1038/nature14113},
	url = {http://www.nature.com/articles/nature14113},
	author = {Wei, S. Shawn and Wiens, Douglas A. and Zha, Yang and Plank, Terry and Webb, Spahr C. and Blackman, Donna K. and Dunn, Robert A. and Conder, James A.}
}
@article {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 {froment_imaging_2014,
	title = {Imaging along-strike variations in mechanical properties of the Gofar transform fault, East Pacific Rise},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {119},
	number = {9},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2014JB011270},
	pages = {7175{\textendash}7194},
	abstract = {AbstractA large part of global plate motion on mid-ocean ridge transform faults (RTFs) is not accommodated as major earthquakes. When large earthquakes do occur, they often repeat quasiperiodically. We focus here on the high slip rate (\~{}14 cm/yr) Gofar transform fault on the equatorial East Pacific Rise. This fault is subdivided into patches that slip during Mw 5.5{\textendash}6 earthquakes every 5 to 6 years. These patches are separated by rupture barriers that accommodate slip through swarms of smaller events and/or aseismic creep. We performed an imaging study to investigate which spatiotemporal variations of the fault zone properties control this segmentation in mechanical behavior and could explain the specific behavior of RTFs at the global scale. We adopt a double-difference approach in a joint inversion of active air gun shots and microseismicity recorded for 1 year. This data set includes the 2008 Mw 6 Gofar earthquake. The along-strike P wave velocity structure reveals an abrupt transition between the barrier area, characterized by a damaged fault zone of 10{\textendash}20\% reduced Vp and a nearly intact fault zone in the asperity area. The importance of the strength of the damage zone on the mechanical behavior is supported by the temporal S wave velocity changes which suggest increased damage within the barrier area, during the week preceding the Mw 6 earthquake. Our results support the conclusion that extended highly damaged zones are the key factor in limiting the role of major earthquakes to accommodate plate motion along RTFs.},
	keywords = {double-difference tomography, fault zone, imaging, mid-ocean ridge transform fault},
	issn = {2169-9356},
	doi = {10.1002/2014JB011270},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2014JB011270},
	author = {Froment, B. and McGuire, J. J. and van der Hilst, R. D. and Gou{\'e}dard, P. and Roland, E. C. and Zhang, H. and Collins, J. A.}
}
@article {godin_interferometry_2014,
	title = {Interferometry of infragravity waves off New Zealand},
	journal = {Journal of Geophysical Research: Oceans},
	volume = {119},
	number = {2},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2013JC009395},
	pages = {1103{\textendash}1122},
	abstract = {AbstractWave interferometry is a remote sensing technique, which is increasingly employed in helioseismology, seismology, and acoustics to retrieve parameters of the propagation medium from two-point cross-correlation functions of random wavefields. Here we apply interferometry to yearlong records of seafloor pressure at 28 locations off New Zealand{\textquoteright}s South Island to investigate propagation and directivity properties of infragravity waves away from shore. A compressed cross-correlation function technique is proposed to make the interferometry of dispersive waves more robust, decrease the necessary noise averaging time, and simplify retrieval of quantitative information from noise cross correlations. The emergence of deterministic wave arrivals from cross correlations of random wavefields is observed up to the maximum range of 692 km between the pressure sensors in the array. Free, linear waves with a strongly anisotropic distribution of power flux density are found to be dominant in the infragravity wavefield. Lowest-frequency components of the infragravity wavefield are largely isotropic. The anisotropy has its maximum in the middle of the spectral band and decreases at the high-frequency end of the spectrum. Highest anisotropy peaks correspond to waves coming from portions of the New Zealand{\textquoteright}s shoreline. Significant contributions are also observed from waves propagating along the coastline and probably coming from powerful sources in the northeast Pacific. Infragravity wave directivity is markedly different to the east and to the west of the South Island. The northwest coast of the South Island is found to be a net source of the infragravity wave energy.},
	keywords = {deep ocean, random wave fields, Surface gravity waves, wave interferometry},
	issn = {2169-9291},
	doi = {10.1002/2013JC009395},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2013JC009395},
	author = {Godin, Oleg A. and Zabotin, Nikolay A. and Sheehan, Anne F. and Collins, John A.}
}
@article {ball_joint_2014,
	title = {A joint Monte Carlo analysis of seafloor compliance, Rayleigh wave dispersion and receiver functions at ocean bottom seismic stations offshore New Zealand},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {15},
	number = {12},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2014GC005412},
	pages = {5051{\textendash}5068},
	abstract = {Teleseismic body-wave imaging techniques such as receiver function analysis can be notoriously difficult to employ on ocean-bottom seismic data due largely to multiple reverberations within the water and low-velocity sediments. In lieu of suppressing this coherently scattered noise in ocean-bottom receiver functions, these site effects can be modeled in conjunction with shear velocity information from seafloor compliance and surface wave dispersion measurements to discern crustal structure. A novel technique to estimate 1-D crustal shear-velocity profiles from these data using Monte Carlo sampling is presented here. We find that seafloor compliance inversions and P-S conversions observed in the receiver functions provide complimentary constraints on sediment velocity and thickness. Incoherent noise in receiver functions from the MOANA ocean bottom seismic experiment limit the accuracy of the practical analysis at crustal scales, but synthetic recovery tests and comparison with independent unconstrained nonlinear optimization results affirm the utility of this technique in principle.},
	keywords = {Monte Carlo, New Zealand, OBS receiver function, seafloor compliance, sediment shear modes, surface waves},
	issn = {1525-2027},
	doi = {10.1002/2014GC005412},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2014GC005412},
	author = {Ball, Justin S. and Sheehan, Anne F. and Stachnik, Joshua C. and Lin, Fan-Chi and Collins, John A.}
}
@article {collins_pn_2014,
	title = {Pn anisotropy beneath the South Island of New Zealand and implications for distributed deformation in continental lithosphere},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {119},
	number = {10},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2014JB011233},
	pages = {7745{\textendash}7767},
	abstract = {Pn travel times from regional earthquakes recorded both by stations on New Zealand and by ocean bottom seismographs deployed offshore indicate anisotropy in the uppermost mantle beneath the region. The largest anisotropy of 8\% ({\textpm}2\%, 1σ) lies beneath the deforming part of the South Island to just off its West Coast, a zone roughly 100{\textendash}200 km wide. The fastest propagation is aligned N60{\textdegree}E ({\textpm}3{\textdegree}), essentially parallel to the largely strike-slip relative plate motion since 20 Ma, also N60{\textdegree}E. The magnitude of anisotropy decreases abruptly northwest and southeast of this zone, and on the southeast side of the island, the orientation of fastest propagation is between N32{\textdegree}W and N-S. The N60{\textdegree}E orientation of fast propagation is consistent with finite strain within the uppermost part of the mantle lithosphere if the measured 850 km of displacement of the Pacific plate past the Australia plate is spread over a region with a width of 100{\textendash}200 km. The agreement of this orientation of fast propagation with the orientation or relative plate motion suggests the possibility of but does not require some dynamic recrystallization in rock as cold as 500{\textendash}800{\textdegree}C, where Peierls creep seems to be the likely deformation mechanism. Such a strain distribution matches deformation of a thin viscous sheet that obeys a constitutive relationship of the form , where is the average strain rate and τ is the operative deviatoric stress, with an average value of n ≈ 3{\textendash}10. Presumably, the NW-SE fast propagation in the region southeast of the island results from strain that precedes the Cenozoic deformation that has shaped the island.},
	keywords = {anisotropy, Lithosphere, New Zealand, Pn},
	issn = {2169-9356},
	doi = {10.1002/2014JB011233},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2014JB011233},
	author = {Collins, John A. and Molnar, Peter}
}
@article {wolfson-schwehr_relationship_2014,
	title = {The relationship between seismicity and fault structure on the Discovery transform fault, East Pacific Rise},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {15},
	number = {9},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2014GC005445},
	pages = {3698{\textendash}3712},
	abstract = {There is a global seismic moment deficit on mid-ocean ridge transform faults, and the largest earthquakes on these faults do not rupture the full fault area. We explore the influence of physical fault structure, including step-overs in the fault trace, on the seismic behavior of the Discovery transform fault, 4S on the East Pacific Rise. One year of microseismicity recorded during a 2008 ocean bottom seismograph deployment (24,377 0 ML 4.6 earthquakes) and 24 years of Mw 5.4 earthquakes obtained from the Global Centroid Moment Tensor catalog, are correlated with surface fault structure delineated from high-resolution multibeam bathymetry. Each of the 15 5.4 Mw 6.0 earthquakes that occurred on Discovery between 1 January 1990 and 1 April 2014 was relocated into one of five distinct rupture patches using a teleseismic surface wave cross-correlation technique. Microseismicity was relocated using the HypoDD relocation algorithm. The western fault segment of Discovery (DW) is composed of three zones of varying structure and seismic behavior: a zone with no large events and abundant microseismicity, a fully coupled zone with large earthquakes, and a complex zone with multiple fault strands and abundant seismicity. In general, microseismicity is reduced within the patches defined by the large, repeating earthquakes. While the extent of the large rupture patches on DW correlates with physical features in the bathymetry, step-overs in the primary fault trace are not observed at patch boundaries, suggesting along-strike heterogeneity in fault zone properties controls the size and location of the large events.},
	keywords = {earthquakes, East Pacific Rise, fault structure, transform fault},
	issn = {1525-2027},
	doi = {10.1002/2014GC005445},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2014GC005445},
	author = {Wolfson-Schwehr, Monica and Boettcher, Margaret S. and McGuire, Jeffrey J. and Collins, John A.}
}
@article {zietlow_upper_2014,
	title = {Upper mantle seismic anisotropy at a strike-slip boundary: South Island, New Zealand},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {119},
	number = {2},
	year = {2014},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/2013JB010676},
	pages = {1020{\textendash}1040},
	abstract = {New shear wave splitting measurements made from stations onshore and offshore the South Island of New Zealand show a zone of anisotropy 100{\textendash}200 km wide. Measurements in central South Island and up to approximately 100 km offshore from the west coast yield orientations of the fast quasi-shear wave nearly parallel to relative plate motion, with increased obliquity to this orientation observed farther from shore. On the eastern side of the island, fast orientations rotate counterclockwise to become nearly perpendicular to the orientation of relative plate motion approximately 200 km off the east coast. Uniform delay times between the fast and slow quasi-shear waves of nearly 2.0 s onshore continue to stations approximately 100 km off the west coast, after which they decrease to 1 s at 200 km. Stations more than 300 km from the west coast show little to no splitting. East coast stations have delay times around 1 s. Simple strain fields calculated from a thin viscous sheet model (representing distributed lithospheric deformation) with strain rates decreasing exponentially to both the northwest and southeast with e-folding dimensions of 25{\textendash}35 km (approximately 75\% of the deformation within a zone 100{\textendash}140 km wide) match orientations and amounts of observed splitting. A model of deformation localized in the lithosphere and then spreading out in the asthenosphere also yields predictions consistent with observed splitting if, at depths of 100{\textendash}130 km below the lithosphere, typical grain sizes are 6{\textendash}7 mm.},
	keywords = {mantle lithosphere, MOANA, New Zealand, ocean bottom seismometers, seismic anisotropy, South Island},
	issn = {2169-9356},
	doi = {10.1002/2013JB010676},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2013JB010676},
	author = {Zietlow, Daniel W. and Sheehan, Anne F. and Molnar, Peter H. and Savage, Martha K. and Hirth, Greg and Collins, John A. and Hager, Bradford H.}
}
@article {dunn_crustal_2013,
	title = {Crustal construction and magma chamber properties along the Eastern Lau Spreading Center},
	journal = {Earth and Planetary Science Letters},
	volume = {371-372},
	year = {2013},
	month = {jun},
	pages = {112{\textendash}124},
	abstract = {The L-SCAN active-source seismic tomography experiment maps the crustal structure and magmatic system along a 120-km-long section of the back-arc Eastern Lau Spreading Center (ELSC), where the ridge undergoes abrupt changes in morphology and composition associated with increasing proximity to the Tofua volcanic arc. Using this dataset, we picked \textasciitilde197,000 P-wave travel times from 57 seismic airgun lines recorded at 83 ocean bottom seismograph stations, and inverted for a 3-D P-wave velocity image. The seismic images reveal a prominent, but narrow, seismic low velocity volume (LVV) located beneath all surveyed ridge segments, consistent with the high temperatures and melt of a crustal magmatic system. Crustal magmatic systems thus underlie spreading axes even where previous seismic reflection surveys did not detect magma lens reflectors, accounting for the heat source of high-temperature hydrothermal vents in these areas. The top of the LVV closely follows the ridge axis and steps across three overlapping spreading centers. As the offset of the overlap increases, the LVV becomes increasingly discontinuous across the ridge limbs. Surprisingly, the LVV is as much as twice as wide, but deeper, in the northern part of the ridge system where the crust is thinner, as compared to the LVV beneath the southern segments, where the crust is relatively thicker. The width of the LVV may be modulated by the degree of deep hydrothermal activity or temporal variations in melt supply, and thus may not correlate directly with the average melt flux as indicated by crustal thickness. Over the past 4Myr, the location of the ridge has swept across different mantle compositional domains, and the crust produced at the ridge formed a zoned pattern. The interpretation is that thick, highly porous, volcanic layers with felsic compositions cap regions of thick crust; thinner volcanic layers of basaltic composition cap regions of thinner crust. The zonal pattern indicates that the influence of slab-derived water on crustal construction has substantially decreased over time.},
	keywords = {back-arc basin, Eastern Lau Spreading Center, magma chamber, mantle melting, mid-ocean ridge, seismic tomography},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2013.04.008},
	url = {https://www.sciencedirect.com/science/article/pii/S0012821X13001891},
	author = {Dunn, Robert A. and Martinez, Fernando and Conder, James A.}
}
@article {stephen_deep_2013,
	title = {Deep seafloor arrivals in long range ocean acoustic propagation},
	journal = {The Journal of the Acoustical Society of America},
	volume = {134},
	number = {4},
	year = {2013},
	note = {Publisher: Acoustical Society of America},
	month = {oct},
	pages = {3307{\textendash}3317},
	abstract = {Ocean bottom seismometer observations at 5000 m depth during the long-range ocean acoustic propagation experiment in the North Pacific in 2004 show robust, coherent, late arrivals that are not readily explained by ocean acoustic propagation models. These {\textquotedblleft}deep seafloor{\textquotedblright} arrivals are the largest amplitude arrivals on the vertical particle velocity channel for ranges from 500 to 3200 km. The travel times for six (of 16 observed) deep seafloor arrivals correspond to the sea surface reflection of an out-of-plane diffraction from a seamount that protrudes to about 4100 m depth and is about 18 km from the receivers. This out-of-plane bottom-diffracted surface-reflected energy is observed on the deep vertical line array about 35 dB below the peak amplitude arrivals and was previously misinterpreted as in-plane bottom-reflected surface-reflected energy. The structure of these arrivals from 500 to 3200 km range is remarkably robust. The bottom-diffracted surface-reflected mechanism provides a means for acoustic signals and noise from distant sources to appear with significant strength on the deep seafloor.},
	issn = {0001-4966},
	doi = {10.1121/1.4818845},
	url = {https://asa.scitation.org/doi/full/10.1121/1.4818845},
	author = {Stephen, Ralph A. and Thompson Bolmer, S. and Udovydchenkov, Ilya A. and Worcester, Peter F. and Dzieciuch, Matthew A. and Andrew, Rex K. and Mercer, James A. and Colosi, John A. and Howe, Bruce M.}
}
@article {sumy_mechanisms_2013,
	title = {The Mechanisms of Earthquakes and Faulting in the Southern Gulf of California},
	journal = {Bulletin of the Seismological Society of America},
	volume = {103},
	number = {1},
	year = {2013},
	pages = {487{\textendash}506},
	abstract = {Accurate earthquake locations and their focal mechanisms can illuminate the distribution and mode of deformation at rifted continental margins. The Pacific{\textendash}North America (Pa{\textendash}NA) plate boundary within the Gulf of California (GoC) provides an excellent opportunity to explore the evolution and kinematics of rifting, as continental extension in the north transitions to seafloor spreading in the south. From October 2005 to October 2006, an array of eight four-component ocean-bottom seismographs deployed in the GoC recorded seismicity as part of the Sea of Cortez Ocean-Bottom Array (SCOOBA) experiment. By combining the data with those from the onshore Network of Autonomously Recording Seismographs (NARS)-Baja array, we detect and locate \~{}700 earthquakes (Mw~2.2{\textendash}6.6) mainly along the northwest{\textendash}southeast-striking transform faults that delineate the plate boundary. For 36 events (Mw~3.5{\textendash}6.6) with high signal-to-noise ratio in a long-period (10{\textendash}20~s) band, we determine deviatoric moment tensors and associated double-couple focal mechanisms by regional waveform inversion. Many focal mechanisms are consistent with right-lateral strike-slip faulting along the Pa{\textendash}NA transform fault system, which suggests that the transform faults primarily accommodate seismic deformation within the gulf. In addition, we capture a swarm of events on Baja California along the right-lateral northwest{\textendash}southeast-striking Las Viboras{\textendash}El Azufre fault, which may be related to ongoing geothermal activity and volcanic deformation within the peninsula. The combination of high-resolution earthquake locations and focal mechanisms improves our understanding of the distribution of seismic deformation within the greater extensional zone in the southern GoC.Online Material: Earthquake catalog of the 695 events detected and located during our combined on-/offshore deployment of seismometers.},
	issn = {0037-1106},
	doi = {10.1785/0120120080},
	url = {https://doi.org/10.1785/0120120080},
	author = {Sumy, Danielle F. and Gaherty, James B. and Kim, Won-Young and Diehl, Tobias and Collins, John A.}
}
@article {mcguire_millimeter-level_2013,
	title = {Millimeter-level precision in a seafloor geodesy experiment at the Discovery transform fault, East Pacific Rise},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {14},
	number = {10},
	year = {2013},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/ggge.20225},
	pages = {4392{\textendash}4402},
	abstract = {Direct-path acoustic ranging is a promising seafloor geodetic technique for continuous high-resolution monitoring of geodynamical process such as fault slip and magma intrusion. Here we report on a yearlong acoustic ranging experiment conducted across the discovery transform fault at \~{}4{\textdegree}S on the East Pacific Rise. The ranging instruments utilized a novel acoustic signal designed to enhance precision. We find that, after correcting for variations in sound speed at the path end-points, the ranging measurements have a precision of \~{}1 mm over baselines approaching 1 km in length. The primary difficulty in this particular experiment was with the physical stability of the benchmarks, which were deployed free fall from a ship. Despite the stability issues, it appears that the portion of the transform fault that the array covered was locked during the year of our survey. The primary obstacle to continuous, high sample rate, high-precision geodetic monitoring of oceanic ridges and transform faults is now limited to the construction of geodetic monuments that are well anchored into bedrock.},
	keywords = {oceanic transform fault, seafloor geodesy},
	issn = {1525-2027},
	doi = {10.1002/ggge.20225},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ggge.20225},
	author = {McGuire, Jeffrey J. and Collins, John A.}
}
@article {worcester_north_2013,
	title = {The North Pacific Acoustic Laboratory deep-water acoustic propagation experiments in the Philippine Sea},
	journal = {The Journal of the Acoustical Society of America},
	volume = {134},
	number = {4},
	year = {2013},
	note = {Publisher: Acoustical Society of America},
	month = {oct},
	pages = {3359{\textendash}3375},
	abstract = {A series of experiments conducted in the Philippine Sea during 2009{\textendash}2011 investigated deep-water acoustic propagation and ambient noise in this oceanographically and geologically complex region: (i) the 2009 North Pacific Acoustic Laboratory (NPAL) Pilot Study/Engineering Test, (ii) the 2010{\textendash}2011 NPAL Philippine Sea Experiment, and (iii) the Ocean Bottom Seismometer Augmentation of the 2010{\textendash}2011 NPAL Philippine Sea Experiment. The experimental goals included (a) understanding the impacts of fronts, eddies, and internal tides on acoustic propagation, (b) determining whether acoustic methods, together with other measurements and ocean modeling, can yield estimates of the time-evolving ocean state useful for making improved acoustic predictions, (c) improving our understanding of the physics of scattering by internal waves and spice, (d) characterizing the depth dependence and temporal variability of ambient noise, and (e) understanding the relationship between the acoustic field in the water column and the seismic field in the seafloor. In these experiments, moored and ship-suspended low-frequency acoustic sources transmitted to a newly developed distributed vertical line array receiver capable of spanning the water column in the deep ocean. The acoustic transmissions and ambient noise were also recorded by a towed hydrophone array, by acoustic Seagliders, and by ocean bottom seismometers.},
	issn = {0001-4966},
	doi = {10.1121/1.4818887},
	url = {https://asa.scitation.org/doi/full/10.1121/1.4818887},
	author = {Worcester, Peter F. and Dzieciuch, Matthew A. and Mercer, James A. and Andrew, Rex K. and Dushaw, Brian D. and Baggeroer, Arthur B. and Heaney, Kevin D. and D{\textquoteright}Spain, Gerald L. and Colosi, John A. and Stephen, Ralph A. and Kemp, John N. and Howe, Bruce M. and Van Uffelen, Lora J. and Wage, Kathleen E.}
}
@article {godin_power_2013,
	title = {Power spectra of infragravity waves in a deep ocean},
	journal = {Geophysical Research Letters},
	volume = {40},
	number = {10},
	year = {2013},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/grl.50418},
	pages = {2159{\textendash}2165},
	abstract = {AbstractInfragravity waves (IGWs) play an important role in coupling wave processes in the ocean, ice shelves, atmosphere, and the solid Earth. Due to the paucity of experimental data, little quantitative information is available about power spectra of IGWs away from the shore. Here we use continuous, yearlong records of pressure at 28 locations on the seafloor off New Zealand{\textquoteright}s South Island to investigate spectral and spatial distribution of IGW energy. Dimensional analysis of diffuse IGW fields reveals universal properties of the power spectra observed at different water depths and leads to a simple, predictive model of the IGW spectra. While sources of IGWs off New Zealand are found to have a flat power spectrum, the IGW energy density has a pronounced dependence on frequency and local water depth as a result of the interaction of the waves with varying bathymetry.},
	keywords = {deep ocean, random wave fields, Surface gravity waves, wave spectra},
	issn = {1944-8007},
	doi = {10.1002/grl.50418},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/grl.50418},
	author = {Godin, Oleg A. and Zabotin, Nikolay A. and Sheehan, Anne F. and Yang, Zhaohui and Collins, John A.}
}
@article {wech_tectonic_2013,
	title = {Tectonic Tremor Recorded by Ocean Bottom Seismometers},
	journal = {Seismological Research Letters},
	volume = {84},
	number = {5},
	year = {2013},
	month = {sep},
	pages = {752{\textendash}758},
	issn = {0895-0695},
	doi = {10.1785/0220120184},
	url = {https://doi.org/10.1785/0220120184},
	author = {Wech, A. G. and Sheehan, A. F. and Boese, C. M. and Townend, J. and Stern, T. A. and Collins, J. A.}
}
@article {yang_character_2012,
	title = {The character of seafloor ambient noise recorded offshore New Zealand: Results from the MOANA ocean bottom seismic experiment},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {13},
	number = {10},
	year = {2012},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2012GC004201},
	abstract = {{We analyze the characteristics of ambient noise recorded on ocean-bottom seismographs using data from the 2009{\textendash}2010 MOANA (Marine Observations of Anisotropy Near Aotearoa) seismic experiment deployed west and east of South Island, New Zealand. Microseism and infragravity noise peaks are clear on data recorded on the vertical channel of the seismometer and on the pressure sensor. The noise levels in the infragravity band (<0.03 Hz) on the horizontal seismometer channels are too high to show the infragravity peak. There is a small difference (\~{}0.25 Hz versus \~{}0.2 Hz) in microseism peak frequencies between the two sides of the South Island on all three seismic channels. Our results show clear depth dependence between the peak frequency of infragravity waves and the water depth. We find that the product of water depth and wave number at the peak frequency is a constant},
	keywords = {continental shelf, infragravity wave, New Zealand, noise, OBS},
	issn = {1525-2027},
	doi = {10.1029/2012GC004201},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2012GC004201},
	author = {Yang, Zhaohui and Sheehan, Anne F. and Collins, John A. and Laske, Gabi}
}
@article {stachnik_determination_2012,
	title = {Determination of New Zealand Ocean Bottom Seismometer Orientation via Rayleigh-Wave Polarization},
	journal = {Seismological Research Letters},
	volume = {83},
	number = {4},
	year = {2012},
	pages = {704{\textendash}713},
	abstract = {Online material: Complete list of earthquakes used in this study.},
	issn = {0895-0695},
	doi = {10.1785/0220110128},
	url = {https://doi.org/10.1785/0220110128},
	author = {Stachnik, J. C. and Sheehan, A. F. and Zietlow, D. W. and Yang, Z. and Collins, J. and Ferris, A.}
}
@article {roland_seismic_2012,
	title = {Seismic velocity constraints on the material properties that control earthquake behavior at the Quebrada-Discovery-Gofar transform faults, East Pacific Rise},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {117},
	number = {B11},
	year = {2012},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2012JB009422},
	abstract = {Mid-ocean ridge transform faults (RTFs) vary strongly along strike in their ability to generate large earthquakes. This general observation suggests that local variations in material properties along RTFs exert a primary control on earthquake rupture dynamics. We explore these relationships by examining the seismic structure of two RTFs that have distinctly different seismic coupling. We determine the seismic velocity structure at the Gofar and Quebrada faults on the East Pacific Rise (EPR) using P wave traveltime tomography with data from two active-source wide-angle refraction lines crossing the faults. We image low-velocity zones (LVZs) at both faults, where P wave velocities are reduced by as much as 0.5{\textendash}1.0 km/s (\~{}10{\textendash}20\%) within a several kilometer wide region. At the Gofar fault, the LVZ extends through the entire crust, into the seismogenic zone. We rule out widespread serpentinization as an explanation for the low velocities, owing to the lack of a corresponding signal in the locally measured gravity field. The reduced velocities can be explained if the plate boundary region is composed of fault material with enhanced fluid-filled porosity (1.5{\textendash}8\%). Local seismic observations indicate that the high-porosity region lies within a \~{}10 km long portion of the fault that fails in large swarms of microearthquakes and acts as a barrier to the propagation of large (M \~{} 6.0) earthquakes. Tomographic images of fault structure combined with observed earthquake behavior suggest that EPR transform segments capable of generating large earthquakes have relatively intact gabbro within the seismogenic zone, whereas segments that slip aseismically or via earthquake swarms are composed of highly fractured, >=2 km wide damage zones that extend throughout the crust.},
	keywords = {fault structure, marine seismology, rupture dynamics, tomography, transform fault},
	issn = {2156-2202},
	doi = {10.1029/2012JB009422},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2012JB009422},
	author = {Roland, Emily and Lizarralde, Dan and McGuire, Jeffrey J. and Collins, John A.}
}
@article {collins_seismicity_2012,
	title = {Seismicity of the Atlantis Massif detachment fault, 30{\textdegree}N at the Mid-Atlantic Ridge},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {13},
	number = {10},
	year = {2012},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2012GC004210},
	abstract = {At the oceanic core complex that forms the Atlantis Massif at 30{\textdegree}N on the Mid-Atlantic Ridge, slip along the detachment fault for the last 1.5{\textendash}2 Ma has brought lower crust and mantle rocks to the seafloor. Hydroacoustic data collected between 1999 and 2003 suggest that seismicity occurred near the top of the Massif, mostly on the southeastern section, while detected seismicity along the adjacent ridge axis was sparse. In 2005, five short-period ocean bottom seismographs (OBS) were deployed on and around the Massif as a pilot experiment to help constrain the distribution of seismicity in this region. Analysis of six months of OBS data indicates that, in contrast to the results of the earlier hydroacoustic study, the vast majority of the seismicity is located within the axial valley. During the OBS deployment, and within the array, seismicity was primarily composed of a relatively constant background rate and two large aftershock sequences that included 5 teleseismic events with magnitudes between 4.0 and 4.5. The aftershock sequences were located on the western side of the axial valley adjacent to the Atlantis Massif and close to the ridge-transform intersection. They follow Omori{\textquoteright}s law, and constitute more than half of the detected earthquakes. The OBS data also indicate a low but persistent level of seismicity associated with active faulting within the Atlantis Massif in the same region as the hydroacoustically detected seismicity. Within the Massif, the data indicate a north-south striking normal fault, and a left-lateral, strike-slip fault near a prominent, transform-parallel, north-facing scarp. Both features could be explained by changes in the stress field at the inside corner associated with weak coupling on the Atlantis transform. Alternatively, the normal faulting within the Massif might indicate deformation of the detachment surface as it rolls over to near horizontal from an initial dip of about 60{\textdegree} beneath the axis, and the strike-slip events may indicate transform-parallel movement on adjacent detachment surfaces.},
	keywords = {Atlantis Massif, hydroacoustic, Mid-Atlantic Ridge, oceanic detachment fault, seismicity, T-phase},
	issn = {1525-2027},
	doi = {10.1029/2012GC004210},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2012GC004210},
	author = {Collins, John A. and Smith, Deborah K. and McGuire, Jeffrey J.}
}
@article {collins_shear_2012,
	title = {Shear wave splitting at the Hawaiian hot spot from the PLUME land and ocean bottom seismometer deployments},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {13},
	number = {2},
	year = {2012},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2011GC003881},
	abstract = {We examine upper mantle anisotropy across the Hawaiian Swell by analyzing shear wave splitting of teleseismic SKSwaves recorded by the PLUME broadband land and ocean bottom seismometer deployments. Mantle anisotropy beneath the oceans is often attributed to flow-induced lattice-preferred orientation of olivine. Splitting observations may reflect a combination of both fossil lithospheric anisotropy and anisotropy due to present-day asthenospheric flow, and here we address the question whether splitting provides diagnostic information on possible asthenospheric plume flow at Hawaii. We find that the splitting fast directions are coherent and predominantly parallel to the fossil spreading direction, suggesting that shear wave splitting dominantly reflects fossil lithospheric anisotropy. The signature of anisotropy from asthenospheric flow is more subtle, although it could add some perturbation to lithospheric splitting. The measured delay times are typically 1 s or less, although a few stations display larger splitting delays of 1{\textendash}2 s. The variability in the delay times across the different stations indicates differences in the degree of anisotropy or in the thickness of the anisotropic layer or in the effect of multilayer anisotropy. Regions with smaller splitting times may have experienced processes that modified the lithosphere and partially erased the fossil anisotropy; alternatively, asthenospheric splitting may either constructively add to or destructively subtract from lithospheric splitting to produce the observed variability in delay times.},
	keywords = {Hawaii, splittting},
	issn = {1525-2027},
	doi = {10.1029/2011GC003881},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2011GC003881},
	author = {Collins, John A. and Wolfe, Cecily J. and Laske, Gabi}
}
@article {mcguire_variations_2012,
	title = {Variations in earthquake rupture properties along the Gofar transform fault, East Pacific Rise},
	journal = {Nature Geoscience},
	volume = {5},
	number = {5},
	year = {2012},
	note = {Number: 5 Publisher: Nature Publishing Group},
	month = {may},
	pages = {336{\textendash}341},
	abstract = {Mid-ocean ridge transform faults experience more foreshocks than continental faults, yet the mainshock rarely ruptures the entire fault. Analysis of seismic data from the Gofar transform fault at the East Pacific Rise indicates that the foreshock region has different material properties from the mainshock region, and acts as a barrier to rupture propagation.},
	keywords = {seismology},
	issn = {1752-0908},
	doi = {10.1038/ngeo1454},
	url = {https://www.nature.com/articles/ngeo1454},
	author = {McGuire, Jeffrey J. and Collins, John A. and Gou{\'e}dard, Pierre and Roland, Emily and Lizarralde, Dan and Boettcher, Margaret S. and Behn, Mark D. and van der Hilst, Robert D.}
}
@article {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 {yao_structure_2011,
	title = {Structure of young East Pacific Rise lithosphere from ambient noise correlation analysis of fundamental- and higher-mode Scholte-Rayleigh waves},
	journal = {Nouveaux d{\'e}veloppements de l{\textquoteright}imagerie et du suivi temporel {\`a} partir du bruit sismique},
	volume = {343},
	number = {8},
	year = {2011},
	month = {sep},
	pages = {571{\textendash}583},
	abstract = {Inter-station Green{\textquoteright}s functions estimated from ambient noise studies have been widely used to investigate crustal structure. However, most studies are restricted to continental areas and use fundamental-mode surface waves only. In this study, we recover inter-station surface (Scholte-Rayleigh) wave empirical Green{\textquoteright}s function (EGFs) of both the fundamental- and the first-higher mode using one year of continuous seismic noise records on the vertical component from 28 ocean bottom seismographs deployed in the Quebrada/Discovery/Gofar transform faults region on the East Pacific Rise. The average phase-velocity dispersion of the fundamental mode (period band 2{\textendash}30s) and the first-higher mode (period band 3{\textendash}7s) from all EGFs are used to invert for the 1-D average, shear-velocity structure in the crust and uppermost mantle using a model-space search algorithm. The preferred shear-velocity models reveal low velocities (4.29km/s) between Moho and 25km depth below sea-surface, suggesting the absence of a fast uppermost mantle lid in this young (0{\textendash}2Myr) oceanic region. An even more pronounced low-velocity zone, with shear velocities \~{}3.85km/s, appears at a depth between 25{\textendash}40km below sea-surface. Along with previous results, our study indicates that the shear velocity in the uppermost oceanic mantle increases with increasing seafloor age, consistent with age-related lithospheric cooling. R{\'e}sum{\'e} Les fonctions de Green estim{\'e}es {\`a} partir de l{\textquoteright}analyse du bruit ambiant ont beaucoup {\'e}t{\'e} utilis{\'e}es pour {\'e}tudier la structure de la cro{\^u}te terrestre. La plupart de ces travaux sont toutefois limit{\'e}s aux zones continentales, et ne consid{\`e}rent que le mode fondamental des ondes de surface. Dans cette {\'e}tude, les fonctions de Green empiriques (EGFs) du mode fondamental et du premier mode sup{\'e}rieur des ondes de surface (Scholte-Rayleigh) sont reconstruites {\`a} partir d{\textquoteright}une ann{\'e}e d{\textquoteright}enregistrements continus de la composante verticale du bruit sismique sur 28 ocean bottom seismometers (OBSs) d{\'e}ploy{\'e}s dans la r{\'e}gion des failles transformantes Quebrada/Discovery/Gofar, le long de la dorsale oc{\'e}anique du Pacifique Est. La dispersion moyenne des vitesses de phase du mode fondamental (dans la bande de p{\'e}riode 2{\textendash}30s) et du premier mode sup{\'e}rieur (dans la bande 3{\textendash}7s), issus des EGFs, est utilis{\'e}e pour d{\'e}terminer un mod{\`e}le moyen 1D de la vitesse des ondes de cisaillement dans la cro{\^u}te et le manteau sup{\'e}rieur {\`a} partir d{\textquoteright}un algorithme de recherche dans l{\textquoteright}espace mod{\`e}le. Le mod{\`e}le de vitesse des ondes de cisaillement r{\'e}sultant pr{\'e}sente une couche de faible vitesse (4,29km/s) entre le Moho et 25km sous le niveau de la mer, ce qui sugg{\`e}re l{\textquoteright}absence de couche superficielle rapide dans le manteau sup{\'e}rieur de cette jeune r{\'e}gion oc{\'e}anique (0{\textendash}2millions d{\textquoteright}ann{\'e}es). Une zone de faible vitesse encore plus prononc{\'e}e, avec une vitesse de cisaillement de \~{}3,85km/s, appara{\^\i}t entre 25 et 40km sous le niveau de la mer. Combin{\'e}e avec des r{\'e}sultats ant{\'e}rieurs, notre {\'e}tude montre que la vitesse de cisaillement dans le manteau oc{\'e}anique sup{\'e}rieur augmente avec l{\textquoteright}{\^a}ge du fond oc{\'e}anique, ce qui est en accord avec le refroidissement dans le temps de la lithosph{\`e}re.},
	keywords = {ambient noise, Bruit ambiant, Dorsale Est Pacifique, East Pacific Rise, Fundamental- and higher-mode Scholte-Rayleigh waves, Lithosphere, Low-velocity zone, Manteau oc{\'e}anique sup{\'e}rieur, Modes fondamental et sup{\'e}rieur des ondes de Scholte-Rayleigh, Oceanic Uppermost Mantle, Zone de faible vitesse},
	issn = {1631-0713},
	doi = {10.1016/j.crte.2011.04.004},
	url = {https://www.sciencedirect.com/science/article/pii/S1631071311000952},
	author = {Yao, Huajian and Gou{\'e}dard, Pierre and Collins, John A. and McGuire, Jeffrey J. and van der Hilst, Robert D.}
}
@article {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_characterizing_2008,
	title = {Characterizing the Caribbean{\textendash}South American plate boundary at 64{\textdegree}W using wide-angle seismic data},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {113},
	number = {B7},
	year = {2008},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2007JB005329},
	abstract = {We present wide-angle velocity modeling results from profile 64{\textdegree}W of the Broadband Ocean-Land Investigation of Venezuela and the Antilles arc Region (BOLIVAR) project. Line 64W is a 460-km-long, approximately north-south, onshore-offshore reflection/refraction transect located approximately at 64{\textdegree}W longitude. The profile extends across the transform plate boundary between the southeastern Caribbean (CAR) and South American (SA) plates. East of the profile the plate boundary bends to the north, and SA subducts beneath CAR. We utilize first-arrival tomography to resolve a smooth velocity field for the sediments and upper/middle crust and then use a layered approach to resolve a sharp velocity contrast for the Moho, simultaneously inverting refracted Pn and reflected PmP arrivals. We image crustal and upper mantle structure across the plate boundary zone. We interpret that the strike-slip system that accommodates relative motion between CAR and SA extends near vertically through the entire crust and offsets the Moho. We see no evidence supporting a major component of convergence, and rather than a wide boundary zone of overlapping lithospheric plates, we interpret the plate boundary to be confined to the 33-km-wide, near-vertical strike-slip system. Previously interpreted thrust faults flanking the strike-slip system appear to be confined to the upper/middle crust and may be related to the detachment of subducting South American lithosphere at the southern terminus of the Lesser Antilles subduction zone east of 64{\textdegree}W.},
	keywords = {El Pilar, velocity modeling, Venezuela margin},
	issn = {2156-2202},
	doi = {10.1029/2007JB005329},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2007JB005329},
	author = {Clark, S. A. and Zelt, C. A. and Magnani, M. B. and Levander, A.}
}
@article {christeson_crustal_2008,
	title = {Crustal structure of the Caribbean{\textendash}northeastern South America arc-continent collision zone},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {113},
	number = {B8},
	year = {2008},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2007JB005373},
	abstract = {We present the results of a 568-km-long regional wide-angle seismic profile conducted in the southeastern Caribbean that crosses an active island arc, a remnant arc, two basins possibly floored by oceanic crust, an allochthonous terrane of forearc affinity, and the passive margin of northern South America. The velocity structures of the Late Cretaceous Aves Ridge remnant arc and Miocene and younger Lesser Antilles arc are remarkably similar, which implies that magmatic processes have remained moderately steady over time. Crustal thickness is \~{}26 km at the Aves Ridge and \~{}24 km at the Lesser Antilles arc. In comparison to the Izu-Bonin and Aleutian arcs, the Lesser Antilles arc is thinner and has no evidence for a lower crustal cumulate layer, which is consistent with the estimated low magma production rates of the Lesser Antilles arc. Crustal thickness beneath the Grenada and Tobago basins is 4{\textendash}10 km, and the velocity structure suggests that these basins could be floored by oceanic crust. A decrease of \~{}1 km/s in average seismic velocity of the upper crust is observed from NW to SE across the North Coast fault zone; we argue that this marks the suture between the far-traveled Caribbean arc and the passive margin of the South American continent. Current strike-slip motion between the Caribbean and South American plates is located \~{}30 km to the south, and thus material originally deposited on the South American passive margin has now been transferred to the Caribbean plate.},
	keywords = {arc-continent collision, Lesser Antilles, SE Caribbean},
	issn = {2156-2202},
	doi = {10.1029/2007JB005373},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2007JB005373},
	author = {Christeson, Gail L. and Mann, Paul and Escalona, Alejandro and Aitken, Trevor J.}
}
@article {holmes_crustal_2008,
	title = {Crustal thickness variations along the Southeast Indian Ridge (100{\textdegree}{\textendash}116{\textdegree}E) from 2-D body wave tomography},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {9},
	number = {12},
	year = {2008},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2008GC002152},
	abstract = {Axial morphology along the Southeast Indian Ridge (SEIR) systematically changes from an axial high to a deep rift valley at a nearly uniform intermediate spreading rate between 100{\textdegree}{\textendash}116{\textdegree}E, west of the Australian-Antarctic Discordance (AAD). Basalt geochemistry has a consistent Indian{\textendash}mid-ocean ridge basalt (MORB) type isotopic signature, so changes in axial topography are attributed to variations in both mantle temperature and melt supply. Wide-angle seismic refraction lines were shot to four ocean bottom hydrophones within SEIR segments P1, P2, S1, and T, where each segment is characterized by a different morphology. We constructed 2-D crustal velocity models by jointly inverting hand-picked P wave refraction (Pg) and Moho reflection (PmP) traveltime data using a top-down, minimum-structure methodology. The results show a 1.5 km eastward decrease in crustal thickness across the study area, with segment averages ranging from 6.1 km at P1 to 4.6 km at T. Melt generation models require a \~{}30{\textdegree}C decrease in mantle temperature toward the AAD to account for the crustal thickness trend. Significant changes in axial morphology accompany small-scale variations in crustal thickness, consistent with models of crustal accretion where ridge topography is determined by a balance between mantle temperature, melt supply, and cooling from hydrothermal circulation. Layer 3 thins by 3.0 km as layer 2 thickens by 1.4 km between segments P1 and T, reflecting the eastward decrease in melt supply and increase in melt lens depth. The trade-off in seismic layers may be explained by models relating the increase in overburden pressure on a deepening melt lens to the volume of magma erupted into the upper crust rather than cooling at depth to form new lower crustal material.},
	keywords = {crustal structure, mid-ocean ridge, oceanic crust, seismic refraction, seismic tomography, Southeast Indian Ridge},
	issn = {1525-2027},
	doi = {10.1029/2008GC002152},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2008GC002152},
	author = {Holmes, R. Chadwick and Tolstoy, Maya and Cochran, James R. and Floyd, Jacqueline S.}
}
@article {clark_identification_2008,
	title = {Identification and tectonic implications of a tear in the South American plate at the southern end of the Lesser Antilles},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {9},
	number = {11},
	year = {2008},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2008GC002084},
	abstract = {In the southeast corner of the Caribbean, westward subduction of (Atlantic) oceanic South America beneath the Lesser Antilles transitions to east-west transform motion between continental South America and the Caribbean plate. This geometry requires negatively buoyant, subducting, oceanic South American lithosphere to progressively detach from positively buoyant, continental South American lithosphere. The most widely accepted model is slab break-off, with oblique arc-continent collision and northwest dipping, continental subduction precipitating narrow rifting in the subducting slab. In contrast, the subduction-transform edge propagator (STEP) model conceptualizes progressive detachment along a vertical, dip-slip tear through the lithosphere, with stress focused at the edge of the propagating transform boundary. We present four types of seismic data to resolve the ongoing lithospheric detachment: local seismicity, receiver functions, wide-angle seismic velocity inversion, and a regional, balanced cross section constrained by petroleum industry data. These four data sets image a near-vertical tear extending through the entire lithosphere, revealing a key mechanism for the structural evolution of Venezuela.},
	keywords = {jelly sandwich, lithospheric detachment, mantle dynamics, slab break-off, STEP, tear},
	issn = {1525-2027},
	doi = {10.1029/2008GC002084},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2008GC002084},
	author = {Clark, S. A. and Sobiesiak, M. and Zelt, C. A. and Magnani, M. B. and Miller, M. S. and Bezada, M. J. and Levander, A.}
}
@article {clark_negligible_2008,
	title = {Negligible convergence and lithospheric tearing along the Caribbean{\textendash}South American plate boundary at 64{\textdegree}W},
	journal = {Tectonics},
	volume = {27},
	number = {6},
	year = {2008},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2008TC002328},
	abstract = {Prior studies of the Caribbean{\textendash}South American plate boundary have suffered from poor constraint on the structure of the crust and uppermost mantle. We use a recent wide-angle velocity model from the Broadband Ocean-Land Investigation of Venezuela and the Antilles arc Region project to constrain new seismic reflection data and previously published line drawing interpretations of the Caribbean{\textendash}South American plate boundary at 64{\textdegree}W. Though commonly characterized as obliquely convergent, we determine that convergence is negligible in our study area. Previous estimates of Miocene to present north-south shortening onshore eastern Venezuela have commonly been 115 km or higher, but we constrain shortening to \~{}35 km onshore, with an additional \~{}30 km offshore. With such minor convergence, we conclude that uplift and basin subsidence in eastern Venezuela does not derive from typical collisional orogeny. Instead, the largely vertical tectonics likely result from mantle dynamics associated with an eastward propagating, near-vertical tear in the lithosphere along the former passive margin.},
	keywords = {El Pilar fault, Serrania del Interior, STEP fault},
	issn = {1944-9194},
	doi = {10.1029/2008TC002328},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2008TC002328},
	author = {Clark, S. A. and Levander, A. and Magnani, M. B. and Zelt, C. A.}
}
@article {calvert_three-dimensional_2008,
	title = {Three-dimensional crustal structure of the Mariana island arc from seismic tomography},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {113},
	number = {B1},
	year = {2008},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2007JB004939},
	abstract = {A three-dimensional (3-D) seismic refraction survey was acquired over the Mariana volcanic arc at 14.5{\textendash}18.5{\textdegree}N and 145{\textendash}147{\textdegree}E. First-arrival traveltimes from this survey and from a separate 2-D survey acquired approximately perpendicular to the arc have been simultaneously inverted for a 3-D P wave velocity model using seismic tomography subject to smoothness constraints. The active arc, which initiated only 3{\textendash}4 Ma ago, has an average crustal thickness of 18 km. Approximately 40 km to the east the inactive remnant of the rifted Eocene arc has an average crustal thickness of 21 km, due primarily to a thicker lower-crustal layer with velocities of 6.5{\textendash}7.0 km s-1. Crustal production clearly varies both temporally and spatially, with some crustal layers, including the igneous fore-arc crust, varying in thickness by a factor of up to 2 along strike. Average P wave velocities within the upper crust of the modern arc are 240{\textendash}360 m s-1 lower than in the Eocene arc but are 280 m s-1 higher within the lower crust. Middle crust with velocities of 6.0{\textendash}6.5 km s-1 is best developed beneath the Eocene arc. These results suggest an evolution of arc structure with increasing age: We infer closure of fractures and porosity in the upper crust through hydrothermal circulation and a reduction in the mafic character of the middle to lower crust as a result of intracrustal differentiation. Although tonalitic rocks may predominate in the transition from upper to middle crust, the bulk of the crust is essentially basaltic.},
	keywords = {crust, Mariana arc, seismic tomography},
	issn = {2156-2202},
	doi = {10.1029/2007JB004939},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2007JB004939},
	author = {Calvert, Andrew J. and Klemperer, Simon L. and Takahashi, Narumi and Kerr, Bryan C.}
}
@article {canales_crustal_2007,
	title = {Crustal structure of the Trans-Atlantic Geotraverse (TAG) segment (Mid-Atlantic Ridge, 26{\textdegree}10'N): Implications for the nature of hydrothermal circulation and detachment faulting at slow spreading ridges},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {8},
	number = {8},
	year = {2007},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2007GC001629},
	abstract = {New seismic refraction data reveal that hydrothermal circulation at the Trans-Atlantic Geotraverse (TAG) hydrothermal field on the Mid-Atlantic Ridge at 26{\textdegree}10'N is not driven by energy extracted from shallow or mid-crustal magmatic intrusions. Our results show that the TAG hydrothermal field is underlain by rocks with high seismic velocities typical of lower crustal gabbros and partially serpentinized peridotites at depth as shallow as 1 km, and we find no evidence for low seismic velocities associated with mid-crustal magma chambers. Our tomographic images support the hypothesis of Tivey et al. (2003) that the TAG field is located on the hanging wall of a detachment fault, and constrain the complex, dome-shaped subsurface geometry of the fault system. Modeling of our seismic velocity profiles indicates that the porosity of the detachment footwall increases after rotation during exhumation, which may enhance footwall cooling. However, heat extracted from the footwall is insufficient for sustaining long-term, high-temperature, hydrothermal circulation at TAG. These constraints indicate that the primary heat source for the TAG hydrothermal system must be a deep magma reservoir at or below the base of the crust.},
	keywords = {crustal structure, detachment faulting, Mid-Atlantic Ridge, slow spreading ridge, TAG hydrothermal field},
	issn = {1525-2027},
	doi = {10.1029/2007GC001629},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2007GC001629},
	author = {Canales, J. Pablo and Sohn, Robert A. and deMartin, Brian J.}
}
@article {demartin_kinematics_2007,
	title = {Kinematics and geometry of active detachment faulting beneath the Trans-Atlantic Geotraverse (TAG) hydrothermal field on the Mid-Atlantic Ridge},
	journal = {Geology},
	volume = {35},
	number = {8},
	year = {2007},
	month = {aug},
	pages = {711{\textendash}714},
	abstract = {Newly acquired seismic refraction and microearthquake data from the Trans-Atlantic Geotraverse (TAG) segment of the Mid-Atlantic Ridge at 26{\textdegree}N reveal for the first time the geometry and seismic character of an active oceanic detachment fault. Hypocenters from 19,232 microearthquakes observed during an eight month ocean bottom seismometer deployment form an \~{}15-km-long, dome-shaped fault surface that penetrates to depths \&gt;7 km below the seafloor on a steeply dipping (\~{}70{\textdegree}) interface. A tomographic model of compressional-wave velocities demonstrates that lower crustal rocks are being exhumed in the detachment footwall, which appears to roll over to a shallow dip of 20{\textdegree} {\textpm} 5{\textdegree} and become aseismic at a depth of \~{}3 km. Outboard of the detachment the exhumed lithosphere is deformed by ridge-parallel, antithetical normal faulting. Our results suggest that hydrothermal fluids at the TAG field exploit the detachment fault to extract heat from a region near the crust-mantle interface over long periods of time.},
	issn = {0091-7613},
	doi = {10.1130/G23718A.1},
	url = {https://doi.org/10.1130/G23718A.1},
	author = {deMartin, Brian J. and Sohn, Robert A. and Pablo Canales, Juan and Humphris, Susan E.}
}
