Evolution of fault-surface roughness with slip

Abstract

Research Article| March 01, 2007 Evolution of fault-surface roughness with slip Amir Sagy; Amir Sagy 1Department of Earth and Planetary Sciences, University of California-Santa Cruz, Santa Cruz, California 95064, USA Search for other works by this author on: GSW Google Scholar Emily E. Brodsky; Emily E. Brodsky 1Department of Earth and Planetary Sciences, University of California-Santa Cruz, Santa Cruz, California 95064, USA Search for other works by this author on: GSW Google Scholar Gary J. Axen Gary J. Axen 2Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Amir Sagy 1Department of Earth and Planetary Sciences, University of California-Santa Cruz, Santa Cruz, California 95064, USA Emily E. Brodsky 1Department of Earth and Planetary Sciences, University of California-Santa Cruz, Santa Cruz, California 95064, USA Gary J. Axen 2Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, USA Publisher: Geological Society of America Received: 25 Jul 2006 Revision Received: 09 Nov 2006 Accepted: 20 Nov 2006 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2007) 35 (3): 283–286. https://doi.org/10.1130/G23235A.1 Article history Received: 25 Jul 2006 Revision Received: 09 Nov 2006 Accepted: 20 Nov 2006 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Amir Sagy, Emily E. Brodsky, Gary J. Axen; Evolution of fault-surface roughness with slip. Geology 2007;; 35 (3): 283–286. doi: https://doi.org/10.1130/G23235A.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 Principal slip surfaces in fault zones accommodate most of the displacement during earthquakes. The topography of these surfaces is integral to earthquake and fault mechanics, but is practically unknown at the scale of earthquake slip. We use new laser-based methods to map exposed fault surfaces over scales of 10 µm to 120 m. These data provide the first quantitative evidence that fault-surface roughness evolves with increasing slip. Thousands of profiles ranging from 10 µm to >100 m in length show that small-slip faults (slip <1 m) are rougher than large-slip faults (slip 10-100 m or more) parallel to the slip direction. Surfaces of small-slip faults have asperities over the entire range of observed scales, while large-slip fault surfaces are polished, with RMS values of <3 mm on profiles as long as 1-2 m. The large-slip surfaces show smooth, elongate, quasi-elliptical bumps that are meters long and as high as ∼1 m. We infer that these bumps evolve during fault maturation. This difference in geometry implies that the nucleation, growth, and termination of earthquakes on evolved faults are fundamentally different than on new ones. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.