Library science

Sediment

Tectonics

Columbia university

Pore water pressure

Observatory

Geotechnical engineering

Geomorphology

Archaeology

Computer science

Subduction

Seismology

Geology

Oceanography

Paleontology

Physics

Astronomy

Sociology

Geological survey

Nova scotia

Art history

Media studies

History

Research Article| February 09, 2018 Connections between subducted sediment, pore-fluid pressure, and earthquake behavior along the Alaska megathrust Jiyao Li; Jiyao Li 1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964, USA Search for other works by this author on: GSW Google Scholar Donna J. Shillington; Donna J. Shillington * 1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964, USA *E-mail: djs@ldeo.columbia.edu Search for other works by this author on: GSW Google Scholar Demian M. Saffer; Demian M. Saffer 2Department of Geosciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA Search for other works by this author on: GSW Google Scholar Anne Bécel; Anne Bécel 1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964, USA Search for other works by this author on: GSW Google Scholar Mladen R. Nedimović; Mladen R. Nedimović 3Department of Earth Sciences, Dalhousie University, Halifax, B3H 4R2 Nova Scotia, Canada Search for other works by this author on: GSW Google Scholar Harold Kuehn; Harold Kuehn 3Department of Earth Sciences, Dalhousie University, Halifax, B3H 4R2 Nova Scotia, Canada Search for other works by this author on: GSW Google Scholar Spahr C. Webb; Spahr C. Webb 1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964, USA Search for other works by this author on: GSW Google Scholar Katie M. Keranen; Katie M. Keranen 4Earth and Atmospheric Sciences, Cornell University, Ithaca, New York 14850, USA Search for other works by this author on: GSW Google Scholar Geoffrey A. Abers Geoffrey A. Abers 4Earth and Atmospheric Sciences, Cornell University, Ithaca, New York 14850, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Jiyao Li 1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964, USA Donna J. Shillington * 1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964, USA Demian M. Saffer 2Department of Geosciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA Anne Bécel 1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964, USA Mladen R. Nedimović 3Department of Earth Sciences, Dalhousie University, Halifax, B3H 4R2 Nova Scotia, Canada Harold Kuehn 3Department of Earth Sciences, Dalhousie University, Halifax, B3H 4R2 Nova Scotia, Canada Spahr C. Webb 1Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964, USA Katie M. Keranen 4Earth and Atmospheric Sciences, Cornell University, Ithaca, New York 14850, USA Geoffrey A. Abers 4Earth and Atmospheric Sciences, Cornell University, Ithaca, New York 14850, USA *E-mail: djs@ldeo.columbia.edu Publisher: Geological Society of America Received: 25 Jul 2017 Revision Received: 27 Dec 2017 Accepted: 07 Jan 2018 First Online: 09 Feb 2018 Online Issn: 1943-2682 Print Issn: 0091-7613 © 2018 Geological Society of America Geology (2018) 46 (4): 299–302. https://doi.org/10.1130/G39557.1 Article history Received: 25 Jul 2017 Revision Received: 27 Dec 2017 Accepted: 07 Jan 2018 First Online: 09 Feb 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Jiyao Li, Donna J. Shillington, Demian M. Saffer, Anne Bécel, Mladen R. Nedimović, Harold Kuehn, Spahr C. Webb, Katie M. Keranen, Geoffrey A. Abers; Connections between subducted sediment, pore-fluid pressure, and earthquake behavior along the Alaska megathrust. Geology 2018;; 46 (4): 299–302. doi: https://doi.org/10.1130/G39557.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search 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 (600–900 m) subducted sediment layer that is characterized by low seismic velocities and elevated pore pressure (λ* ≈ 0.4–0.8). 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* < 0.2–0.3). 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. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Connections between subducted sediment, pore-fluid pressure, and earthquake behavior along the Alaska megathrust