Regional stress field around the Taigu fault zone in Shanxi Province,China  

作　　者：Bin Li Zihong Li Mathilde B.S?rensen Reidar L?vlie Liqiang Liu Kuvvet Atakan 

机构地区：[1]Earthquake Administration of Shanxi Province [2]Department of Earth Science,University of Bergen [3]State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration

出　　处：《Earthquake Science》2015年第5期333-345,共13页地震学报（英文版）

基　　金：partly funded by Open Fund of State Key Laboratory of Earthquake Dynamics,CEA(LED2011B05);the Foundation for the Returned Overseas of Shanxi Province(121);the National Science Fund of Shanxi Province(Youth,2010021005)

摘　　要：A comprehensive study on regional stress field around the Taigu fault zone in Shanxi Province, China, was performed in this study. To get a better understanding of the present-day stress status in this area, 31 focal mecha- nisms of ML 〉3 earthquakes since 1965 were compiled, and the best stress tensor was then inverted based on the database. Additionally, magnetic fabrics along the Taigu fault zone were investigated to get an indication of the regional stress field in the past. Our results show that the present-day stress field around the Taigu fault zone is characterized by astable NW-SE extension with a strike- slip component, consistent with the geological surveys and recent GPS data. Results from magnetic fabrics indicate that the orientations of principal stress axes from magnetic fabrics of sedimentary rocks in Neogene coincide to the orientations of principal stress axes from focal mecha- nisms. The south segment of the Taigu fault displays more complicated magnetic fabrics and more activity of mod- erate earthquakes. It is connected with the Mianshan west fault and intersects with NW-SE striking Fenyang fault and the north fault of the Lingshi uplift at the south edge of Taiyuan basin. This may be the area needing more atten- tion in terms of seismic risk along the Taigu fault.A comprehensive study on regional stress field around the Taigu fault zone in Shanxi Province, China, was performed in this study. To get a better understanding of the present-day stress status in this area, 31 focal mecha- nisms of ML 〉3 earthquakes since 1965 were compiled, and the best stress tensor was then inverted based on the database. Additionally, magnetic fabrics along the Taigu fault zone were investigated to get an indication of the regional stress field in the past. Our results show that the present-day stress field around the Taigu fault zone is characterized by astable NW-SE extension with a strike- slip component, consistent with the geological surveys and recent GPS data. Results from magnetic fabrics indicate that the orientations of principal stress axes from magnetic fabrics of sedimentary rocks in Neogene coincide to the orientations of principal stress axes from focal mecha- nisms. The south segment of the Taigu fault displays more complicated magnetic fabrics and more activity of mod- erate earthquakes. It is connected with the Mianshan west fault and intersects with NW-SE striking Fenyang fault and the north fault of the Lingshi uplift at the south edge of Taiyuan basin. This may be the area needing more atten- tion in terms of seismic risk along the Taigu fault.

关 键 词：Focal mechanisms Stress tensor inversion Magnetic fabric Taigu fault Shanxi rift 

分 类 号：P315.2[天文地球—地震学]