Dynamic weakening by nanoscale smoothing during high-velocity fault slip

Abstract

Research Article| July 01, 2013 Dynamic weakening by nanoscale smoothing during high-velocity fault slip Xiaofeng Chen; Xiaofeng Chen 1School of Geology and Geophysics, University of Oklahoma, Norman, Oklahoma 73019, USA Search for other works by this author on: GSW Google Scholar Andrew S. Madden; Andrew S. Madden 1School of Geology and Geophysics, University of Oklahoma, Norman, Oklahoma 73019, USA Search for other works by this author on: GSW Google Scholar Barry R. Bickmore; Barry R. Bickmore 2Department of Geological Sciences, Brigham Young University, Provo, Utah 84602, USA Search for other works by this author on: GSW Google Scholar Ze’ev Reches Ze’ev Reches * 1School of Geology and Geophysics, University of Oklahoma, Norman, Oklahoma 73019, USA *E-mail: reches@ou.edu. Search for other works by this author on: GSW Google Scholar Author and Article Information Xiaofeng Chen 1School of Geology and Geophysics, University of Oklahoma, Norman, Oklahoma 73019, USA Andrew S. Madden 1School of Geology and Geophysics, University of Oklahoma, Norman, Oklahoma 73019, USA Barry R. Bickmore 2Department of Geological Sciences, Brigham Young University, Provo, Utah 84602, USA Ze’ev Reches * 1School of Geology and Geophysics, University of Oklahoma, Norman, Oklahoma 73019, USA *E-mail: reches@ou.edu. Publisher: Geological Society of America Received: 24 Oct 2012 Revision Received: 07 Feb 2013 Accepted: 10 Feb 2013 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2013 Geological Society of America Geology (2013) 41 (7): 739–742. https://doi.org/10.1130/G34169.1 Article history Received: 24 Oct 2012 Revision Received: 07 Feb 2013 Accepted: 10 Feb 2013 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Xiaofeng Chen, Andrew S. Madden, Barry R. Bickmore, Ze’ev Reches; Dynamic weakening by nanoscale smoothing during high-velocity fault slip. Geology 2013;; 41 (7): 739–742. doi: https://doi.org/10.1130/G34169.1 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 Slip during large earthquakes occurs along faults that are hundreds of kilometers long, yet the dynamic weakening that drives these earthquakes is controlled by nano- to micro-scale frictional processes. We analyzed these processes along experimental faults that slipped at rates approaching seismic velocity, and which displayed intense dynamic weakening of 50%–70%. Sheared fault surfaces were extracted, and then atomic force microscopy was used to (1) measure friction on a sub-micron scale, and (2) determine the three-dimensional morphology at the nano- to micro-scale. The sheared surfaces developed a prevalent anisotropy with a weaker and smoother axis along the slip direction. The nanoscale friction coefficient correlates well with sheared-surface roughness: the friction coefficients dropped only on surfaces with root mean square (RMS) values of <100 nm, while rougher surfaces showed no weakening. Our analysis indicates that slip smoothing at high slip velocities can be an effective mechanism of dynamic weakening. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.