@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 {barcheck_alaska_2020,
	title = {The Alaska Amphibious Community Seismic Experiment},
	journal = {Seismological Research Letters},
	volume = {91},
	number = {6},
	year = {2020},
	month = {08/2020},
	pages = {3054{\textendash}3063},
	abstract = {The Alaska Amphibious Community Seismic Experiment (AACSE) is a shoreline-crossing passive- and active-source seismic experiment that took place from May 2018 through August 2019 along an \~{}700  km long section of the Aleutian subduction zone spanning Kodiak Island and the Alaska Peninsula. The experiment featured 105 broadband seismometers; 30 were deployed onshore, and 75 were deployed offshore in Ocean Bottom Seismometer (OBS) packages. Additional strong-motion instruments were also deployed at six onshore seismic sites. Offshore OBS stretched from the outer rise across the trench to the shelf. OBSs in shallow water (\&lt;262  m depth) were deployed with a trawl-resistant shield, and deeper OBSs were unshielded. Additionally, a number of OBS-mounted strong-motion instruments, differential and absolute pressure gauges, hydrophones, and temperature and salinity sensors were deployed. OBSs were deployed on two cruises of the R/V Sikuliaq in May and July 2018 and retrieved on two cruises aboard the R/V Sikuliaq and R/V Langseth in August{\textendash}September 2019. A complementary 398-instrument nodal seismometer array was deployed on Kodiak Island for four weeks in May{\textendash}June 2019, and an active-source seismic survey on the R/V Langseth was arranged in June 2019 to shoot into the AACSE broadband network and the nodes. Additional underway data from cruises include seafloor bathymetry and sub-bottom profiles, with extra data collected near the rupture zone of the 2018 Mw~7.9 offshore-Kodiak earthquake. The AACSE network was deployed simultaneously with the EarthScope Transportable Array (TA) in Alaska, effectively densifying and extending the TA offshore in the region of the Alaska Peninsula. AACSE is a community experiment, and all data were made available publicly as soon as feasible in appropriate repositories.},
	issn = {0895-0695},
	doi = {10.1785/0220200189},
	url = {https://doi.org/10.1785/0220200189},
	author = {Barcheck, Grace and Abers, Geoffrey A. and Adams, Aubreya N. and B{\'e}cel, Anne and Collins, John and Gaherty, James B. and Haeussler, Peter J. and Li, Zongshan and Moore, Ginevra and Onyango, Evans and Roland, Emily and Sampson, Daniel E. and Schwartz, Susan Y. and Sheehan, Anne F. and Shillington, Donna J. and Shore, Patrick J. and Webb, Spahr and Wiens, Douglas A. and Worthington, Lindsay L.}
}
@article {becel_evidence_2020,
	title = {Evidence for a Prolonged Continental Breakup Resulting From Slow Extension Rates at the Eastern North American Volcanic Rifted Margin},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {125},
	number = {9},
	year = {2020},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2020JB020093},
	pages = {e2020JB020093},
	abstract = {When continental rifting is accompanied by localized magmatism under extensional stress, the breakup duration can be short and the continent/ocean transition sharp, as mantle melts are thought to be efficient at heating and weakening the lithosphere. This mode of rifting has been invoked for the Eastern North American Margin (ENAM) based on the existing geophysical data. Here, we present results from multichannel seismic profiles from the ENAM Community Seismic Experiment offshore North Carolina, U.S. Our survey area encompasses both the East Coast Magnetic Anomaly (ECMA) and the Blake Spur Magnetic Anomaly (BSMA), which lies 200-km farther seaward. Our prestack depth-migrated seismic images reveal major changes in the structure of the igneous crust across the BSMA. Between the ECMA and BSMA, we image a proto-oceanic domain of rough, faulted, and thin igneous crust. The roughness of this oceanic crust is similar to modern ultraslow spreading environments which involve the continued presence of a pre-existing lithospheric lid. Seaward of the BSMA the basement is smooth, and the crust is relatively thick, which is typical for Jurassic oceanic crust. Across the BSMA, we image a step up in basement and crustal root, which we interpret to represent complete lithospheric breakup and a transition to steady-state seafloor spreading in agreement with coincident refraction results. Our results would also indicate low extension rates in the final stages of rifting that may have influenced the thermal structure of the lithosphere and could explain the delay for continental breakup. All of these observations show that although continental rifting between eastern North America and northwest Africa was assisted by magmatic activity, it did not lead to rapid localization of extensional strain as previously thought.},
	keywords = {Central Atlantic opening, continental breakup, continental margin, proto-oceanic crust, steady-state seafloor spreading, volcanic rifted margin},
	issn = {2169-9356},
	doi = {10.1029/2020JB020093},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020JB020093},
	author = {B{\'e}cel, Anne and Davis, Joshua K. and Shuck, Brandon D. and Van Avendonk, Harm J. A. and Gibson, James C.}
}
@article {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 {shuck_role_2019,
	title = {The role of mantle melts in the transition from rifting to seafloor spreading offshore eastern North America},
	journal = {Earth and Planetary Science Letters},
	volume = {525},
	year = {2019},
	month = {nov},
	pages = {115756},
	abstract = {The Eastern North American Margin (ENAM) formed in the early Jurassic (\~{}195 Ma) with the breakup of supercontinent Pangea. This rifting event was accompanied by volcanism along the continental shelf of the eastern United States, giving rise to the East Coast Magnetic Anomaly (ECMA). Numerical models show that magmatic diking can assist rifting by reducing the effective stress required to rupture the lithosphere. Therefore, magma-rich rifts can develop a rapid transition from continental breakup to seafloor spreading. Alternatively, the onset of seafloor spreading may be accompanied by a long period of persistent thermal weakening and erosion of the lithosphere. In this paper we present analyses of active-source wide-angle seismic data collected during the 2014 ENAM Community Seismic Experiment in an area that extends farther offshore than previous seismic surveys along the eastern U.S. Seaward of the ECMA lies a zone of thin oceanic crust with high compressional seismic velocity (up to 7.5 km/s in the lower crust), whereas thicker normal oceanic crust lies \~{}200 km farther offshore along another prominent magnetic anomaly, the Blake Spur Magnetic Anomaly (BSMA). We reconcile our seismic images with a petrologic model to evaluate the mantle melting conditions during the late stages of continental breakup and early seafloor spreading in the Central Atlantic. We propose that the zone of thin crust between the ECMA and BSMA with high seismic velocity is best explained by the presence of a \~{}15{\textendash}20 km thick lithospheric lid at the time of early seafloor spreading, which prevented melting in the shallow mantle. Our analysis suggests that the volcanism that produced the nearshore ECMA did not lead to complete lithospheric breakup of the conjugate North American and African margins. Normal seafloor spreading began at the BSMA under a moderately high mantle potential temperature of \~{}1395{\textendash}1420{\textdegree}C, \~{}25 million years after the initial formation of the volcanic margin. These results imply that stretching, thermal weakening, and rupture of the lithosphere may take millions of years, even in the presence of mantle melts.},
	keywords = {continent-ocean transition, continental rifting, eastern North American margin, mantle melting, oceanic crust, seismic tomography},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2019.115756},
	url = {https://www.sciencedirect.com/science/article/pii/S0012821X19304480},
	author = {Shuck, Brandon D. and Van Avendonk, Harm J. A. and B{\'e}cel, Anne}
}
@article {li_connections_2018,
	title = {Connections between subducted sediment, pore-fluid pressure, and earthquake behavior along the Alaska megathrust},
	journal = {Geology},
	volume = {46},
	number = {4},
	year = {2018},
	month = {02/2018},
	pages = {299{\textendash}302},
	abstract = {Variations in pore-fluid pressure along subduction megathrusts are often invoked to explain differences in fault slip behavior between margins. However, many other parameters vary between subduction zones, making it difficult to isolate the causes of elevated pore fluid pressures and their effects on megathrust behavior. Here we show evidence from pre-stack depth migrations of multichannel seismic reflection data along the subduction zone off the Alaska Peninsula for significant, systematic along-strike variations in the thickness, continuity, P-wave velocity, and estimated pore-fluid pressure of the subducting sediment layer that lines the shallow plate interface within 25 km of the trench. These variations appear to correlate with changes in seismicity, locking, and earthquake rupture history. The currently locked and seismically quiet Semidi segment has a continuous, thick (600{\textendash}900 m) subducted sediment layer that is characterized by low seismic velocities and elevated pore pressure (λ* ≈ 0.4{\textendash}0.8). The subducted sediment in the neighboring Shumagin Gap, a region with low geodetic coupling and abundant small earthquakes, is thinner, irregular and has lower pore pressure (λ* \&lt; 0.2{\textendash}0.3). We suggest that the thicker and weakly faulted sediment layer entering the trench at Semidi is associated with a continuous and overpressured sediment layer lining the shallow plate interface, but forms a large coherent asperity as it dewaters and consolidates at greater depths, thus favoring large earthquakes. In contrast, thinner incoming sediment disrupted by outer rise faulting at Shumagin results in a plate interface without elevated pore-fluid pressures, but which is heterogeneous and complex at all depths, contributing to creep and frequent small earthquakes.},
	issn = {0091-7613},
	doi = {10.1130/G39557.1},
	url = {https://doi.org/10.1130/G39557.1},
	author = {Li, Jiyao and Shillington, Donna J. and Saffer, Demian M. and B{\'e}cel, Anne and Nedimovi{\'c}, Mladen R. and Kuehn, Harold and Webb, Spahr C. and Keranen, Katie M. and Abers, Geoffrey A.}
}
@article {becel_tsunamigenic_2017,
	title = {Tsunamigenic structures in a creeping section of the Alaska subduction zone},
	journal = {Nature Geoscience},
	volume = {10},
	number = {8},
	year = {2017},
	note = {Publisher: Nature Publishing Group},
	pages = {609{\textendash}613},
	abstract = {Segments of subduction zones that are capable of generating tsunamigenic earthquakes appear to have characteristic structural configurations. These structures include heterogeneous plate interfaces, a small wedge of deformed sediment at the toe of the overriding plate (the frontal prism), and splay faults in the crust of the overriding plate that root within the plate boundary megathrust. Here we use seismic reflection imaging to show that these features also exist within a creeping segment of the Alaska subduction zone, the Shumagin Gap. We identify an active crustal-scale normal fault system that dips landward and resembles that involved in the 2011 Tohoku-oki earthquake in Japan. We also find that the Shumagin Gap has a small frontal prism, a deep-water splay fault, and that the plate interface here is rough and thinly sedimented. We propose that lateral propagation of rupture from a neighbouring segment into the Shumagin Gap may explain a tsunamigenic earthquake that occurred there in 1788 and that tsunamigenic potential should be considered in hazard assessments for the region. Our results demonstrate that structural configurations similar to those in Tohoku may exist in other subduction zones, including within creeping segments or segments with no record of historical megathrust earthquakes, but are under-recognized. Identifying similar configurations globally may improve our ability to anticipate regions capable of generating large tsunamis.},
	keywords = {Geodynamics, Geology, Natural hazards, seismology, Tectonics},
	issn = {1752-0908},
	doi = {10.1038/ngeo2990},
	url = {https://www.nature.com/articles/ngeo2990},
	author = {B{\'e}cel, Anne and Shillington, Donna J. and Delescluse, Matthias and Nedimovi{\'c}, Mladen R. and Abers, Geoffrey A. and Saffer, Demian M. and Webb, Spahr C. and Keranen, Katie M. and Roche, Pierre-Henri and Li, Jiyao and Kuehn, Harold}
}
@article {shillington_link_2015,
	title = {Link between plate fabric, hydration and subduction zone seismicity in Alaska},
	journal = {Nature Geoscience},
	volume = {8},
	number = {12},
	year = {2015},
	note = {Publisher: Nature Publishing Group},
	pages = {961{\textendash}964},
	abstract = {Subduction carries water into the Earth where it can influence seismicity. Analysis of the structure of the Alaskan subduction zone suggests fluid delivery is influenced by faults in the oceanic plate that formed at the mid-ocean ridge.},
	keywords = {Geodynamics, seismology, Tectonics},
	issn = {1752-0908},
	doi = {10.1038/ngeo2586},
	url = {https://www.nature.com/articles/ngeo2586},
	author = {Shillington, Donna J. and B{\'e}cel, Anne and Nedimovi{\'c}, Mladen R. and Kuehn, Harold and Webb, Spahr C. and Abers, Geoffrey A. and Keranen, Katie M. and Li, Jiyao and Delescluse, Matthias and Mattei-Salicrup, Gabriel A.}
}
@article {Becel2015,
	title = {Origin of dipping structures in fast-spreading oceanic lower crust offshore Alaska imaged by multichannel seismic data},
	journal = {Earth and Planetary Science Letters},
	volume = {424},
	year = {2015},
	month = {aug},
	pages = {26{\textendash}37},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2015.05.016},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X15003052},
	author = {B{\'e}cel, Anne and Shillington, Donna J. and Nedimovi{\'c}, Mladen R. and Webb, Spahr C. and Kuehn, Harold}
}
