Non-Coulomb wedges, wrong-way thrusting, and natural hazards in Cascadia

Research Article| May 01, 2001 Non-Coulomb wedges, wrong-way thrusting, and natural hazards in Cascadia Marc-André Gutscher; Marc-André Gutscher 1GEOMAR, Marine Geodynamics, Wischhofstrasse 1-3, D-24148 Kiel, Germany Search for other works by this author on: GSW Google Scholar Dirk Klaeschen; Dirk Klaeschen 1GEOMAR, Marine Geodynamics, Wischhofstrasse 1-3, D-24148 Kiel, Germany Search for other works by this author on: GSW Google Scholar Ernst Flueh; Ernst Flueh 1GEOMAR, Marine Geodynamics, Wischhofstrasse 1-3, D-24148 Kiel, Germany Search for other works by this author on: GSW Google Scholar Jacques Malavieille Jacques Malavieille 2Laboratoire de Géophysique et Tectonique, Université Montpellier II, F-34095, Montpellier, France Search for other works by this author on: GSW Google Scholar Author and Article Information Marc-André Gutscher 1GEOMAR, Marine Geodynamics, Wischhofstrasse 1-3, D-24148 Kiel, Germany Dirk Klaeschen 1GEOMAR, Marine Geodynamics, Wischhofstrasse 1-3, D-24148 Kiel, Germany Ernst Flueh 1GEOMAR, Marine Geodynamics, Wischhofstrasse 1-3, D-24148 Kiel, Germany Jacques Malavieille 2Laboratoire de Géophysique et Tectonique, Université Montpellier II, F-34095, Montpellier, France Publisher: Geological Society of America Received: 20 Sep 2000 Revision Received: 05 Jan 2001 Accepted: 17 Jan 2001 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2001) 29 (5): 379–382. https://doi.org/10.1130/0091-7613(2001)029<0379:NCWWWT>2.0.CO;2 Article history Received: 20 Sep 2000 Revision Received: 05 Jan 2001 Accepted: 17 Jan 2001 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Marc-André Gutscher, Dirk Klaeschen, Ernst Flueh, Jacques Malavieille; Non-Coulomb wedges, wrong-way thrusting, and natural hazards in Cascadia. Geology 2001;; 29 (5): 379–382. doi: https://doi.org/10.1130/0091-7613(2001)029<0379:NCWWWT>2.0.CO;2 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 Landward vergence in accretionary wedges is an uncommon phenomenon not readily explained by classical Mohr-Coulomb critical wedge theory. Predominantly landward- vergent thrust faults are observed along the Cascadia convergent margin from 45°N to 48°N. We present depth-migrated multichannel seismic images of the internal structure of the accretionary wedge offshore Washington collected during the ORWELL project in 1996. These reveal a high p-wave velocity (≥4 km/s) basal layer that thickens landward and serves as a décollement for a series of overlying landward-vergent thrust faults. Analog modeling using a ductile basal layer consisting of silicone putty produces an array of trenchward-propagating, landward-vergent thrusts and offers a plausible mechanical model for the evolution of these structures. The rheological properties of a basal calcareous mudstone layer offshore Cascadia are discussed in relation to the mechanics of landward vergence and to rapid loading due to the prograding Nitinat and Astoria deep-sea fans. A viscoelastic layer beneath the accretionary wedge is considered to be capable of rupturing during great interplate earthquakes and thus represents an increased risk for both the maximum size of such an event and for the generation of tsunamis. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.