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Slip Along the San Andreas Fault Associated with the Earthquake

Sieh, Kerry E. (1982) Slip Along the San Andreas Fault Associated with the Earthquake. In: The Imperial Valley, California, earthquake of October 15, 1979. Geological Survey professional paper. No.1254. United States Geological Survey , Washington, DC, pp. 155-159.

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Some of the fault slip associated with the 1979 Imperial Valley earthquake occurred along other than the Imperial fault and the Brawley fault zone. More than 90 km to the north of the seismogenic fault, a 39-km-long section of the San Andreas fault developed a discontinuous set of surficial fractures soon after the earthquake. This set of fractures consisted of small left-stepping echelon cracks displaying extensional and dextral components of movement. Average dextral slip was about 4 mm, and slip reached 10 mm at one point along the fault. In one locality the cracks formed between Va and 4Vfe days after the main shock, although slippage at depth may have been nearly simultaneous with the earthquake. In general, this set of breaks duplicates the location, style, and slip magnitude of the set that was mapped in 1968 after the Borrego Mountain, Calif, earthquake. Such near-duplication indicates that this section of the San Andreas fault, in particular, is susceptible to small amounts of triggered slip. Although the reasons for such behavior are far from clear, similar behavior of the Imperial fault before 1979 suggests that this section of the San Andreas fault may generate a moderate earthquake within the next few decades.

Item Type:Book Section
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URLURL TypeDescription
Sieh, Kerry E.0000-0002-7311-2447
Additional Information:© 1982 USGS. The ephemeral nature of evidence for triggered fault slip demanded rapid search and documentation that could not have been accomplished without the assistance of Stephen Cohn, James Conca, Ronald Miller, Michael Nelson, James and Judy Pechmann, Gerald Roth, and Ray Weldon all of the Division of Geological and Planetary Sciences of the California Institute of Technology (CIT). C. R. Alien and R. V. Sharp substantially improved the manuscript. Fieldwork was supported by the Earthquake Research Affiliates of CIT and general Division funds.
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Caltech Earthquake Research AffiliatesUNSPECIFIED
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Caltech Division of Geological and Planetary Sciences3379
Series Name:Geological Survey professional paper
Issue or Number:1254
Record Number:CaltechAUTHORS:20141204-134511467
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:52403
Deposited By: Tony Diaz
Deposited On:04 Dec 2014 23:17
Last Modified:09 Mar 2020 13:19

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