Slow-slip phenomena in Cascadia from 2007 and beyond: A review

Research Article| July 01, 2010 Slow-slip phenomena in Cascadia from 2007 and beyond: A review Joan Gomberg; Joan Gomberg † U.S. Geological Survey, University of Washington, Department of Earth & Space Sciences, Box 351310, Seattle, Washington 98195‑1310, USA †E-mail: gomberg@usgs.gov Search for other works by this author on: GSW Google Scholar the Cascadia 2007 and Beyond Working Group the Cascadia 2007 and Beyond Working Group Search for other works by this author on: GSW Google Scholar Author and Article Information Joan Gomberg † U.S. Geological Survey, University of Washington, Department of Earth & Space Sciences, Box 351310, Seattle, Washington 98195‑1310, USA the Cascadia 2007 and Beyond Working Group †E-mail: gomberg@usgs.gov *Paul Bedrosian, Paul Bodin, Michael Bostock, Michael Brudzinski, Ken Creager, Herb Dragert, Gary Egbert, Abhijit Ghosh, Joe Henton, Heidi Houston, Honn Kao, Pat McCrory, Tim Melbourne, Simon Peacock, Evelyn Roeloffs, Justin Rubinstein, David Schmidt, Anne Trèhu, John Vidale, Kelin Wang, and Aaron Wech. Publisher: Geological Society of America Received: 05 Mar 2010 Revision Received: 05 Mar 2010 Accepted: 05 Mar 2010 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2010 Geological Society of America GSA Bulletin (2010) 122 (7-8): 963–978. https://doi.org/10.1130/B30287.1 Article history Received: 05 Mar 2010 Revision Received: 05 Mar 2010 Accepted: 05 Mar 2010 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Joan Gomberg, the Cascadia 2007 and Beyond Working Group; Slow-slip phenomena in Cascadia from 2007 and beyond: A review. GSA Bulletin 2010;; 122 (7-8): 963–978. doi: https://doi.org/10.1130/B30287.1 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 SocietyGSA Bulletin Search Advanced Search Abstract Recent technological advances combined with more detailed analyses of seismologic and geodetic observations have fundamentally changed our understanding of the ways in which tectonic stresses arising from plate motions are accommodated by slip on faults. The traditional view that relative plate motions are accommodated by a simple cycle of stress accumulation and release on "locked" plate-boundary faults has been revolutionized by the serendipitous discovery and recognition of the significance of slow-slip phenomena, mostly in the deeper reaches of subduction zones. The Cascadia subduction zone, located in the Pacific Northwest of the conterminous United States and adjacent Canada, is an archetype of exploration and learning about slow-slip phenomena. These phenomena are manifest as geodetically observed aseismic transient deformations accompanied by a previously unrecognized class of seismic signals. Although secondary failure processes may be involved in generating the seismic signals, the primary origins of both aseismic and seismic phenomena appear to be episodic fault slip, probably facilitated by fluids, on a plate interface that is critically stressed or weakened. In Cascadia, this transient slip evolves more slowly and over more prolonged durations relative to the slip in earthquakes, and it occurs between the 30- and 40-km-depth contours of the plate interface where information was previously elusive. Although there is some underlying organization that relaxes nearly all the accrued plate-motion stresses along the entirety of Cascadia, we now infer that slow slip evolves in complex patterns indicative of propagating stress fronts. Our new understanding provides key constraints not only on the region where the slow slip originates, but also on the probable characteristics of future megathrust earthquakes in Cascadia. Herein, we review the most significant scientific issues and progress related to understanding slow-slip phenomena in Cascadia and highlight some of their societal implications. We provide a comprehensive review, from the big picture as inferred from studies of regional-scale monitoring data to the details revealed by innovative, focused experiments and new instrumentation. We focus on what has been learned largely since 2007, when several major investments in monitoring and temporary deployments dramatically increased the quality and quantity of available data. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.