Relatively simple through-going fault planes at large-earthquake depth may be concealed by the surface complexity of strike-slip faults

Geological Society, London, Special Publications
By: , and 

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Abstract

At the surface, strike-slip fault stepovers, including abrupt fault bends, are typically regions of complex, often disconnected faults. This complexity has traditionally led geologists studying the hazard of active faults to consider such stepovers as important fault segment boundaries, and to give lower weight to earthquake scenarios that involve rupture through the stepover zone. However, recent geological and geophysical studies of several stepover zones along the San Andreas fault system in California have revealed that the complex nature of the fault zone at the surface masks a much simpler and direct connection at depths associated with large earthquakes (greater than 5 km). In turn, the simplicity of the connection suggests that a stepover zone would provide less of an impediment to through-going rupture in a large earthquake, so that the role of stepovers as segment boundaries has probably been overemphasized. However, counter-examples of fault complexity at depth associated with surface stepovers are known, so the role of stepovers in fault rupture behaviour must be carefully established in each case.

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Publication type Article
Publication Subtype Journal Article
Title Relatively simple through-going fault planes at large-earthquake depth may be concealed by the surface complexity of strike-slip faults
Series title Geological Society, London, Special Publications
DOI 10.1144/SP290.5
Volume 290
Year Published 2007
Language English
Publisher Geological Society
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description 13 p.
First page 189
Last page 201
Country United States
State California
Other Geospatial San Andreas Fault system
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