Stress State of Wenchuan Area
详细信息
- 责任者：Wang Kaiying (State Key Laboratory of Earthquake Dynamics ; Institute of Geology ; China Earthquake Administration ; Beijing 100029 ; China) ; Yu. Rebetsky
- 刊名：Seismology and Geology
- 出版年：2012
- 卷期：34(1)
- 关键词：汶川地震2008 ; Wenchuan earthquake 2008 ; 四川 ; Sichuan Province
- 页码：p.11-16
- 图表：3 illus., 10 refs.
- 分类号：0500
- issnNo：ISSN0253-4967
- isbnNo：CN11-2192/P
摘要
Using the cataclastic analysis method,this paper tries to make an analysis on the focal mechanism data of 486 small earthquakes that occurred at the epicenter of the Wenchuan earthquake and its surrounding areas in more than three years before the 2008 Wenchuan earthquake.The result shows that obvious stress change occurred at the seismic source and its surrounding areas around June 2007 before the Wenchuan earthquake,manifested in two high numerical value areas of abnormal stress state.Meanwhile,the formation process of the above areas was accompanied by the drop of stress level of the Longmenshan central fault.The ultimate strong earthquake occurred on the stress gradient belt between the high stress area and the low stress area.The evolution process of stress level before the Wenchuan earthquake indicates that earthquake nucleation phenomenon turned up before the strong earthquake.One result can be inferred that there was an abnormal process of accelerated movement of the whole Bayankala block before the Wenchuan strong earthquake.