【摘要】 利用近震层析成像方法和2003年新疆巴楚-伽师MS6.8地震走时资料反演得到了震区地下速度图像。结果表明:P波速度在地壳内5km以上表现出了较强的横向非均匀性,反映该区地表的沉积盖层介质特征;在5～22km深度内以NWW和NNE向共轭相交的高速异常带为主,周围速度相对较低。结合构造背景和震源机制解,认为这一区处于NW-SE向的右行走滑和NNE-SSW向的挤压应力双力偶作用下,使得发生的地震有一定的相似性。而NWW和NNE向非均匀性条带为应变能的积累和释放提供了基础,是这次地震发生的一个重要条件。结合宏观调查和石油资料,推断这次地震发生在塔里木盆地西部的一条NWW走向、北倾的巴什托普隐伏断裂上。更多还原

【Abstract】 A detailed tomographic image of the upper crustal structure in Bachu-Jiashi area,Xinjiang Uygur Autonomous Region,is determined by using P-wave arrival time from the Bachu-Jiashi MS6.8 earthquake in 2003.The inversion results as following:Over 5 km depth in the region,P-velocity imaging shows strongly horizontal heterogeneity,reflecting characteristics of sedimentary cover;Between 5～14 km dpeth,P-velocity imaging suggests that there exist two high and conjugated velocity zone encircled with relative low velocity body,one trending NWW and the other NNE.Combined with tectonic background and focal mechanism solutions,it is holded that the character of earthquakes in this region is similar under the action of double-couple,one of which is along NW-SE right-lateral strike-slip couple,and the other is along NNE-SSW compressive stress.The NWW and NNE zone of heterogeneity provided the fundation for strain energy accumulation and release,and was an important condition for occurence of the Bachu-Jiashi earthquake.Combined the macro damage and isoseismic feature from field investigation and the study on petroleum seismic exploration,it is considered that this earthquake occurred on Bashitupu fults in western tarim basin,which trends along NWW and is north dipping.更多还原