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A Structural Interpretation of the Aftershock “Cloud” of the 1992 M_w 7.3 Landers Earthquake

Liu, Jing and Sieh, Kerry and Hauksson, Egill (2003) A Structural Interpretation of the Aftershock “Cloud” of the 1992 M_w 7.3 Landers Earthquake. Bulletin of the Seismological Society of America, 93 (3). pp. 1333-1344. ISSN 0037-1106.

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We analyze the spatial relationship of relocated aftershocks to the principal rupture planes of the M_w 7.3 1992 Landers mainshock from a structural point of view. We find that the aftershocks constitute primarily a several-kilometer-wide damage zone centered on the mainshock rupture planes. The intensity of damage decreases away from the principal faults. Less than half of the aftershocks occurred within 1 km of the mainshock planes, and perhaps only 5% of the aftershocks are candidates for rerupture of the mainshock faults. Moreover, it seems that aftershocks along the Landers rupture have b-values that correlate well with the complexity of the mainshock rupture. Low b-values occur along segments that are simple, whereas higher b-values correlate with sections that are more complex. Thus, structural complexity appears to correlate with a greater relative abundance of small earthquakes. These observations imply that aftershock populations reflect fault populations in the medium surrounding the principal faults rather than the behavior of the mainshock planes themselves.

Item Type:Article
Related URLs:
URLURL TypeDescription Supplement
Sieh, Kerry0000-0002-7311-2447
Hauksson, Egill0000-0002-6834-5051
Additional Information:© 2003 Seismological Society of America. Manuscript received 26 February 2002. We thank A. Rubin, M. Fehler, and an anonymous reviewer for their constructive reviews of this article and K. Richards-Dinger and P. Shearer for sharing their relocated Landers aftershock data set. Discussion with Eric Cowgill improved Figure 10. This research was supported by the Southern California Earthquake Center. SCEC was funded by NSF Cooperative Agreement EAR-8920136 and USGS Cooperative Agreements 14-08-0001-A0899 and 1434-HQ-97AG01718. This research was also partially supported by U.S. Geological Survey Grant 99HQGR0039 to Caltech. This article is Southern California Earthquake Center Contribution 635 and Caltech Seismological Laboratory Contribution Number 8855.
Errata:ERRATUM: Jing Liu, Kerry Sieh, and Egill Hauksson A Structural Interpretation of the Aftershock “Cloud” of the 1992 Mw 7.3 Landers Earthquake Bulletin of the Seismological Society of America, August 2003, v. 93, p. 1873-1874, doi:10.1785/0120030146
Group:Seismological Laboratory
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Southern California Earthquake Center (SCEC)UNSPECIFIED
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Other Numbering System NameOther Numbering System ID
Southern California Earthquake Center (SCEC)635
Caltech Seismological Laboratory8855
Issue or Number:3
Record Number:CaltechAUTHORS:20130215-100908673
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:36949
Deposited By: Tony Diaz
Deposited On:15 Feb 2013 23:53
Last Modified:09 Mar 2020 13:19

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