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Source processes of large earthquakes along the Xianshuihe fault in southwestern China

Zhou, Huilan and Liu, Hsui-Lin and Kanamori, Hiroo (1983) Source processes of large earthquakes along the Xianshuihe fault in southwestern China. Bulletin of the Seismological Society of America, 73 (2). pp. 537-551. ISSN 0037-1106. https://resolver.caltech.edu/CaltechAUTHORS:20140902-145029503

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Abstract

The Xianshuihe fault is one of the most active faults in southwestern China. Recently, three large earthquakes occurred along it in 1967 (M_s = 6.1), 1973 (M_s = 7.5), and 1981 (M_s = 6.8). The 1981 event occurred near the central portion of the fault zone. Modeling of the body and surface waves indicates pure left-lateral strike-slip motion on a vertical fault striking N40°W consistent with the surface trend of the Xianshuihe fault. Two major ruptures are suggested for this source, with a total moment of 1.3 × 10^(26) dyne-cm. The 1973 event occurred about 65 km northwest of the 1981 event and ruptured about 90 km bilaterally along the fault. The body-wave synthetics indicate three main ruptures during faulting within 43 sec, with a total moment of 1.8 × 10^(27) dyne-cm. The mechanisms are similar to the 1981 event, and the average slip is determined to be 3.8 m. The largest aftershock (M_s = 5.9) occurred 1 day after the main event with a normal-fault mechanism striking almost perpendicular to the surface breakage. The 1967 event occurred at the northwestern end of the fault zone, with a strike of N65°E. It had a nearly normalfault mechanism with a seismic moment of 4.5 × 10^(25) dyne-cm. The largest aftershock (M_s = 5.1) occurred 7 hr later with a similar focal mechanism. The primary faulting along the Xianshuihe fault is left-lateral strike-slip, but the normal faulting with strike direction about perpendicular to the Xianshuihe fault trace is common, especially in the northwestern segment. The faulting pattern in this region is consistent with the regional stress field caused by the India-Tibet collision. The normal event which is not on the major fault seems to have more frequent foreshocks and aftershocks than those on the main fault.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://bssa.geoscienceworld.org/content/73/2/537.abstractPublisherArticle
ORCID:
AuthorORCID
Kanamori, Hiroo0000-0001-8219-9428
Additional Information:© 1983, by the Seismological Society of America. Manuscript received 12 July 1982. We wish to give special thanks to Professor Clarence Allen for very kindly supporting this project, reading the manuscript, and making many valuable suggestions. The first author is also grateful to Jeff Given, Ed Corbett, Fumiko Tajima, Gladys Engen, Jeanne Sauber, and Larry Ruff for their help in the use of the computer and the SRO data tape. Research supported by the Division of Earth Sciences, National Science Foundation, NSF Grant EAR-811-6023, and the U.S. Geological Survey Contract 14-08-0001-19265.
Funders:
Funding AgencyGrant Number
NSF Division of Earth SciencesUNSPECIFIED
NSFEAR-811-6023
USGS14-08-0001-19265
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Caltech Division of Geological and Planetary Sciences3784
Issue or Number:2
Record Number:CaltechAUTHORS:20140902-145029503
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140902-145029503
Official Citation: Huilan Zhou, Hsui-Lin Liu, and Hiroo Kanamori Source processes of large earthquakes along the Xianshuihe fault in southwestern China Bulletin of the Seismological Society of America, April 1983, v. 73, p. 537-551
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:49147
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:02 Sep 2014 22:12
Last Modified:09 Mar 2020 13:18

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