Coseismic reverse- and oblique-slip surface faulting generated by the 2008 Mw 7.9 Wenchuan earthquake, China
- 1Institute of Geology, China Earthquake Administration, Beijing 100029, China
- 2Earthquake Administration of Sichuan Province, Chengdu 610041, China
- 3Institut de Physique du Globe de Paris, CNRS-INSU, Paris, France
- 4Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
Abstract
The Mw 7.9 Wenchuan, China, earthquake ruptured two large thrust faults along the Long-menshan thrust belt at the eastern margin of the Tibetan Plateau. This earthquake generated a 240-km-long surface rupture zone along the Beichuan fault and an additional 72-km-long surface rupture zone along the Pengguan fault. Maximum vertical and horizontal offsets of 6.5 m and 4.9 m, respectively, were measured along the Beichuan fault. A maximum vertical offset of 3.5 m was measured along the Pengguan fault. Coseismic surface ruptures, integrated with aftershocks and industry seismic profiles, show that two imbricate structures have ruptured simultaneously, resulting in the largest continental thrust event ever documented. Large oblique thrusting observed during this earthquake indicates that crustal shortening is an important process responsible for the high topography in the region, as everywhere along the edge of Tibetan Plateau.
Footnotes
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↵GSA Data Repository item 2009121, Figures DR1–DR3 and Tables DR1–DR3, is available online at www.geosociety.org/pubs/ft2009.htm, or on request from editing{at}geosociety.org or Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301, USA.
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- Received 1 September 2008.
- Revision received 21 January 2009.
- Accepted 25 January 2009.
- © 2009 Geological Society of America
