地震学报（英文版）2009，Vol.22Issue(2)：109-117,9.DOI:10.1007/s11589-009-0109-z
Spatio-temporal variation and focal mechanism of the Wenchuan Afs8.0 earthquake sequence
Spatio-temporal variation and focal mechanism of the Wenchuan Afs8.0 earthquake sequence
摘要
Abstract
Based on abundant aftershock sequence data of the Wenchuan Ms8.0 earthquake on May 12, 2008, we studied the spatio-temporal variation process and segmentation rupture characteristic. Dense aftershocks distribute along Longmen-shan central fault zone of NE direction and form a narrow strip with the length of 325 km and the depth between several and 40 km. The depth profile (section of NW direction) vertical to the strike of aftershock zone (NE direction) shows anisomer-ous wedgy distribution characteristic of aftershock concentrated regions; it is related to the force form of the Longmenshan nappe tectonic belt. The stronger aftershocks could be divided into northern segment and southern segment apparently and the focal depths of strong aftershocks in the 50 km area between northern segment and southern segment are shallower. It seems like 'to be going to rupture' segment. We also study focal mechanisms and segmentation of strong aftershocks. The principal compressive stress azimuth of aftershock area is WNW direction and the faulting types of aftershocks at southern and northern segment have the same proportion. Because aftershocks distribute on different secondary faults, their focal mechanisms present complex local tectonic stress field. The faulting of seven strong earthquakes on the Longmenshan central fault is mainly characterized by thrust with the component of right-lateral strike-slip. Meantime six strong aftershocks on the Longmenshan back-range fault and Qingchuan fault present strike-slip faulting. At last we discuss the complex segmentation rupture mechanism of the Wenchuan earthquake.关键词
Wenchuan earthquake/strong aftershock/spatio-temporal variation/focal mechanism solutionKey words
Wenchuan earthquake/strong aftershock/spatio-temporal variation/focal mechanism solution分类
天文与地球科学引用本文复制引用
Wanzheng Cheng,Zhiwei Zhang,Xiang Ruan..Spatio-temporal variation and focal mechanism of the Wenchuan Afs8.0 earthquake sequence[J].地震学报（英文版）,2009,22(2):109-117,9.基金项目
The study is supported by National Key Basic Research 973b and National Scientific Technology Support Plan (2006BAC01B02-01-01). （2006BAC01B02-01-01）
