2001年昆仑山口西地震前后山西构造带的应力状态变化  

STRESS CHANGE OF SHANXI TECTONIC BELT RELATED TO THE 2001 M_s 8.1 KUNLUN EARTHQUAKE

作　　者：王凯英[1] 马瑾[1] 刁桂苓[2] Yu. Rebetsky 王晓山[2] 闫小兵[4] 

机构地区：[1]中国地震局地质研究所,地震动力学国家重点实验室,北京100029 [2]河北省地震局,石家庄050021 [3]Institute of Physics of the Earth,Russian Academy of Sciences,moscow123810 [4]山西省地震局,太原030021

出　　处：《地震地质》2012年第4期597-605,共9页Seismology and Geology

基　　金：国家自然科学基金(41172180);中国地震局地质研究所基本科研业务专项(IGCEA1204)共同资助

摘　　要：运用应力状态定量化参数反演方法(CAM),对发生在山西构造带(简称山西带)1967—2010年期间的地震震源机制数据进行了应力状态反演。按这个时段中国发生的强震和山西省中强地震发生时间对数据进行了分时段研究。研究表明,在2001年昆仑山口西8.1级地震前后山西构造带的最大主压应力轴方向发生了明显变化。该地震前山西带最大主压应力轴方向以NW向分布为主;该地震后山西带的最大主压应力轴转变为NE向分布为主。值得强调的是,在1967—2001年11月各时间段中主压应力轴方向没有明显区别,说明该地震对山西带应力状态变化起了重要作用。当最大主压应力轴为NW向分布时,山西带内的SN向构造段与NE向构造段的应力状态均以水平剪切为主;而当最大主压应力轴转为NE向分布时,山西带内SN向构造的应力状态分布表现为水平剪切,而NE向构造的应力状态分布表现为水平拉张。文中对产生应力主轴方向变化的原因进行了分析。与此同时,对山西带强震分布与构造条件的关系也进行了讨论。Shanxi tectonic belt is a historically earthquake-abundant area and the focal distribution of the majority of the strong earthquakes is controlled by the local north-south oriented structures on the tec- tonic belt. Using the cataclastic analysis method （CAM） , we performed an inversion analysis on the stress state of focal mechanism solutions of earthquakes which happened on Shanxi tectonic belt from 1967 to 2010. Results show that spatial distributions of the maximum principal compressive stress axis of Shanxi tectonic belt have changed over time, with two different predominant directions, NW and NE,in different periods of time. When the maximum principal compressive stress axis is oriented in NE direction,the stress state is registered as horizontally shearing and horizontally extension on the north-south and southeast oriented local segments in turn. When the maximum principal compressive stress axis is oriented in NW direction,the stress state of north-south and northeast tectonic segments is primarily registered as horizontally shearing.

关 键 词：CAM方法 山西构造带 应力状态变化 

分 类 号：P553[天文地球—构造地质学]