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Onshore/Offshore Structure of the Juan de Fuca Plate in Northern Cascadia from Bayesian Receiver Function Inversion

2013; Seismological Society of America; Volume: 103; Issue: 5 Linguagem: Inglês

10.1785/0120120310

1943-3573

Camille Brillon, J. F. Cassidy, Stan E. Dosso,

High-pressure geophysics and materials

Brief Report| October 01, 2013 Onshore/Offshore Structure of the Juan de Fuca Plate in Northern Cascadia from Bayesian Receiver Function Inversion C. Brillon; C. Brillon School of Earth and Ocean Sciences, P.O. Box 1700 Stations CSC, University of Victoria, Victoria, British Columbia V8W 2Y2, Canadacamille.brillon@nrcan.gc.ca *Now at Geological Survey of Canada (Natural Resources Canada), P.O. Box 6000, Sidney, British Columbia 48L 4B2, Canada. Search for other works by this author on: GSW Google Scholar J. F. Cassidy; J. F. Cassidy Geological Survey of Canada (Natural Resources Canada), P.O. Box 6000, Sidney, British Columbia 48L 4B2, Canada †Also at School of Earth and Ocean Sciences, P.O. Box 1700 Stations CSC, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada. Search for other works by this author on: GSW Google Scholar S. E. Dosso S. E. Dosso School of Earth and Ocean Sciences, P.O. Box 1700 Stations CSC, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information C. Brillon *Now at Geological Survey of Canada (Natural Resources Canada), P.O. Box 6000, Sidney, British Columbia 48L 4B2, Canada. School of Earth and Ocean Sciences, P.O. Box 1700 Stations CSC, University of Victoria, Victoria, British Columbia V8W 2Y2, Canadacamille.brillon@nrcan.gc.ca J. F. Cassidy †Also at School of Earth and Ocean Sciences, P.O. Box 1700 Stations CSC, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada. Geological Survey of Canada (Natural Resources Canada), P.O. Box 6000, Sidney, British Columbia 48L 4B2, Canada S. E. Dosso School of Earth and Ocean Sciences, P.O. Box 1700 Stations CSC, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada Publisher: Seismological Society of America First Online: 14 Jul 2017 Online ISSN: 1943-3573 Print ISSN: 0037-1106 Bulletin of the Seismological Society of America (2013) 103 (5): 2914–2920. https://doi.org/10.1785/0120120310 Article history First Online: 14 Jul 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation C. Brillon, J. F. Cassidy, S. E. Dosso; Onshore/Offshore Structure of the Juan de Fuca Plate in Northern Cascadia from Bayesian Receiver Function Inversion. Bulletin of the Seismological Society of America 2013;; 103 (5): 2914–2920. doi: https://doi.org/10.1785/0120120310 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 SocietyBulletin of the Seismological Society of America Search Advanced Search Abstract This study applies Bayesian inversion to receiver functions (RFs) to estimate local shear‐wave velocity (VS) structure of the Juan de Fuca (JdF) plate beneath the northern Cascadia subduction zone (CSZ) offshore and onshore Vancouver Island, British Columbia, Canada. We use passive seismic data recorded on NEPTUNE (NorthEast Pacific Time‐series Undersea Networked Experiments) Canada ocean‐bottom seismometers (OBSs), on temporary autonomous KECK Foundation OBSs, and on two land‐based seismometers on Vancouver Island that are part of the Canadian National Seismograph Network (CNSN). Three‐component, broadband recordings of large (⁠⁠), distant (30°–100°) earthquakes are used to compute RFs dominated by locally generated P‐to‐S converted waves. These are subsequently inverted using a nonlinear Bayesian approach that yields optimal profiles of VS, VP (compressional‐wave velocity), and strike and dip angles, as well as quantitative uncertainty estimates for these parameters. The introduction of NEPTUNE Canada helps fill a gap in offshore seismic monitoring. Results from OBS stations indicate a thin oceanic crust at the JdF Ridge which thickens to ∼10 km at the continental slope where sediment thickness also increases to ∼5 km. At OZB, a coastal station, a 6–8 km thick, two‐part low‐velocity zone (LVZ) is imaged at 19 km depth. An LVZ of similar thickness is also observed 34 km beneath PGC, a south‐central Vancouver Island station. The thickness of the LVZ imaged at these two land‐based stations indicates that the oceanic sediments are not subducted but are scraped off the JdF plate and accreted to the North American plate. Determining these VS models at various stages of the CSZ provides a more detailed image of the subducting plate, and therefore contributes valuable new information useful for seismic‐hazard analysis. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.