|Table of Contents|

Regional Characteristics of Tectonic Stress Field and Tectonic Setting of Lushan Earthquake in Sichuan(PDF)

《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]

Issue:
2013年第02期
Page:
99-106
Research Field:
应用地球物理
Publishing date:

Info

Title:
Regional Characteristics of Tectonic Stress Field and Tectonic Setting of Lushan Earthquake in Sichuan
Author(s):
ZHANG Hong-yan;  XIE Fu-ren;  CUI Xiao-feng
Key Laboratory of Crustal Dynamics, Institute of Crustal Dynamics, China Earthquake Administration, Beijing 100085, China
Keywords:
Lushan earthquake;  Longmenshan fault zone;  focal mechanism solution;  maximum principal stress;  tectonic stress field;  stress transition;  tectonic setting
PACS:
P694;P315.2
DOI:
-
Abstract:
In April 20, 2013, a Ms7.0 earthquake hitted Lushan county of Ya’an city, Sichuan province, which was another strong earthquake on Longmenshan foreland thrust zone after Wenchuan earthquake. Basic characteristics and seismogenic tectonic setting of Lushan earthquake were introduced, and regional tectonic stress field was calculated by 172 focal mechanism solutions, especially the directions of maximum principal stress were analyzed based on five different kinds of stress data in Longmenshan stress region. The results indicate that the direction of maximum principal stress in Longmenshan stress region is nearly in EW-direction compressional tectonic setting at present; the direction of maximum principal stress is from NE-SW-direction in Bayan Har block to nearly EW-direction in Longmenshan block, and then to NWW-SEE-direction in South China block, showing clockwise rotation from west to east in spatial distribution; the direction of maximum principal stress is from NEE-SWW-direction in Qaidam-Qinling block to nearly EW-direction in Longmenshan block, and then to NW-SE-direction in Chuandian block, also showing clockwise rotation from south to north in spatial distribution. Transition of stress direction among different blocks indicates that Bayan Har block in the eastern margin of Qinghai-Tibet Plateau moves to the south-east and pushes the Longmenshan block because of the strong stop of Sichuan Basin in South China block, and results in obvious crustal shortening and mountain uplift of Longmenshan foreland thrust zone.

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Last Update: 2013-06-20