Research Article| March 01, 2004 Geophysical investigation of the Denali fault and Alaska Range orogen within the aftershock zone of the October–November 2002, M = 7.9 Denali fault earthquake Michael A. Fisher; Michael A. Fisher 1 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, USA Search for other works by this author on: GSW Google Scholar Warren J. Nokleberg; Warren J. Nokleberg 1 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, USA Search for other works by this author on: GSW Google Scholar Natalia A. Ratchkovski; Natalia A. Ratchkovski 2Geophysical Institute, University of Alaska, P.O. Box 757320, Fairbanks, Alaska 99775, USA Search for other works by this author on: GSW Google Scholar Louise Pellerin; Louise Pellerin 3Green Engineering, 2215 Curtis Street, Berkeley, California 94702, USA Search for other works by this author on: GSW Google Scholar Jonathan M. Glen; Jonathan M. Glen 4 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, USA Search for other works by this author on: GSW Google Scholar Thomas M. Brocher; Thomas M. Brocher 4 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, USA Search for other works by this author on: GSW Google Scholar John Booker John Booker 5Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, Washington 98195, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Michael A. Fisher 1 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, USA Warren J. Nokleberg 1 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, USA Natalia A. Ratchkovski 2Geophysical Institute, University of Alaska, P.O. Box 757320, Fairbanks, Alaska 99775, USA Louise Pellerin 3Green Engineering, 2215 Curtis Street, Berkeley, California 94702, USA Jonathan M. Glen 4 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, USA Thomas M. Brocher 4 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, USA John Booker 5Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, Washington 98195, USA Publisher: Geological Society of America Received: 25 Aug 2003 Revision Received: 19 Nov 2003 Accepted: 25 Nov 2003 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2004) 32 (3): 269–272. https://doi.org/10.1130/G20127.1 Article history Received: 25 Aug 2003 Revision Received: 19 Nov 2003 Accepted: 25 Nov 2003 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 Michael A. Fisher, Warren J. Nokleberg, Natalia A. Ratchkovski, Louise Pellerin, Jonathan M. Glen, Thomas M. Brocher, John Booker; Geophysical investigation of the Denali fault and Alaska Range orogen within the aftershock zone of the October–November 2002, M = 7.9 Denali fault earthquake. Geology 2004;; 32 (3): 269–272. doi: https://doi.org/10.1130/G20127.1 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 The aftershock zone of the 3 November 2002, M = 7.9 earthquake that ruptured along the right-slip Denali fault in south-central Alaska has been investigated by using gravity and magnetic, magnetotelluric, and deep-crustal, seismic reflection data as well as outcrop geology and earthquake seismology. Strong seismic reflections from within the Alaska Range orogen north of the Denali fault dip as steeply as 25°N and extend to depths as great as 20 km. These reflections outline a relict crustal architecture that in the past 20 yr has produced little seismicity. The Denali fault is nonreflective, probably because this fault dips steeply to vertical. The most intriguing finding from geophysical data is that earthquake aftershocks occurred above a rock body, with low electrical resistivity (>10 Ω·m), that is at depths below ∼10 km. Aftershocks of the Denali fault earthquake have mainly occurred shallower than 10 km. A high geothermal gradient may cause the shallow seismicity. Another possibility is that the low resistivity results from fluids, which could have played a role in locating the aftershock zone by reducing rock friction within the middle and lower crust. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.