Complex surface rupturing and related formation mechanisms in the Xiaoyudong area for the 2008 Mw 7.9 Wenchuan Earthquake, China - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Journal of Asian Earth Sciences Year : 2012

Complex surface rupturing and related formation mechanisms in the Xiaoyudong area for the 2008 Mw 7.9 Wenchuan Earthquake, China

Xi-Bin Tan
  • Function : Author
Ren-Mao Yuan
  • Function : Author
Xi-Wei Xu
  • Function : Author
Gui-Hua Chen
  • Function : Author
Yann Klinger
Chung-Pai Chang
  • Function : Author
Jun-Jie Ren
  • Function : Author
Chong Xu
  • Function : Author
  • PersonId : 1330868
Kang Li
  • Function : Author

Abstract

The large oblique reverse slip shock of the 2008 Mw = 7.9 Wenchuan earthquake, China, produced one of the longest and most complicated surface ruptures ever known. The complexity is particularly evident in the Xiaoyudong area, where three special phenomena occurred: the 7 km long Xiaoyudong rupture perpendicular to the Beichuan-Yingxiu fault; the occurrence of two parallel faults rupturing simultaneously, and apparent discontinuity of the Beichuan-Yingxiu rupture. This paper systematically documents these co-seismic rupture phenomena for the Xiaoyudong area. The discussion and results are based on field investigations and analyses of faulting mechanisms and prevalent stress conditions. The results show that the Beichuan-Yingxiu fault formed a 3.5 km wide restraining stepover at the Xiaoyudong area. The Xiaoyudong fault is not a tear fault suggested by previous researches, but a frontal reverse fault induced by the oblique compression at this stepover; it well accommodates the 'deformation gap' of the Beichuan-Yingxiu fault in the Xiaoyudong area. Further, stress along the Peng-Guan fault plane doubles due to a change in dip angle of the Beichuan-Yingxiu fault across the Xiaoyudong restraining stepover. This resulted in two faults rupturing the ground's surface simultaneously, to the north of the Xiaoyudong area. These results are helpful in deepening our understanding of the dynamic processes that produced surface ruptures during the Wenchuan earthquake. Furthermore, the results suggest more attention be focused on the influence of dextral slip component, the change of the control fault's attitude, and property differences in rocks on either side of faults when discussing the formation mechanism of surface ruptures.

Dates and versions

insu-03583025 , version 1 (21-02-2022)

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Xi-Bin Tan, Ren-Mao Yuan, Xi-Wei Xu, Gui-Hua Chen, Yann Klinger, et al.. Complex surface rupturing and related formation mechanisms in the Xiaoyudong area for the 2008 Mw 7.9 Wenchuan Earthquake, China. Journal of Asian Earth Sciences, 2012, 58, pp.132-142. ⟨10.1016/j.jseaes.2012.06.005⟩. ⟨insu-03583025⟩
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