Geology; June 2009; v. 37; no. 6;
p. 515-518; DOI: 10.1130/G25462A.1
© 2009 Geological Society of America
Coseismic reverse- and oblique-slip surface faulting generated by the 2008 Mw 7.9 Wenchuan earthquake, China
Xiwei Xu1,
Xueze Wen2,
Guihua Yu1,
Guihua Chen1,
Yann Klinger3,
Judith Hubbard4 and
John Shaw4
1 Institute of Geology, China Earthquake Administration, Beijing 100029, China
2 Earthquake Administration of Sichuan Province, Chengdu 610041, China
3 Institut de Physique du Globe de Paris, CNRS-INSU, Paris, France
4 Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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.
Copyright © 2009 by Geological Society of America