四川芦山M_S7.0地震余震序列双差定位、震源机制及应力场反演  

Double difference relocation,focal mechanism and stress inversion of Lushan M_S7.0 earthquake sequence

作　　者：赵博[1,2] 高原[1,3] 黄志斌[2] 赵旭[2] 李大虎[1] 

机构地区：[1]中国地震局地球物理研究所,北京100081 [2]中国地震台网中心,北京100045 [3]中国地震局地震预测研究所,北京100036

出　　处：《地球物理学报》2013年第10期3385-3395,共11页Chinese Journal of Geophysics

基　　金：地震行业科研专项(201008001);国家自然科学基金项目(41040034)资助

摘　　要：2013年4月20日发生了四川芦山MS7.0地震,主震中位于青藏地块与华南地块结合部的龙门山断裂带南端.本研究用双差定位法对芦山地震主震及余震序列进行重新定位,得到主震位置为(30.29°N,102.97°E,17.82km)及4100多次余震重新定位结果.利用GSN/IRIS台网和国家台网及四川省区域台网的波形数据对主震及部分余震进行了震源机制解反演.结果表明,主震为一次逆冲地震,根据余震序列分布确定发震断层面走向为200°,震源机制解断层倾角为45°.基于震源断层面解和断层滑动方向,采用力轴张量计算法得到了研究区域的平均主压应力方向约为N112°E.On the 20th of April 2013, Lushan Ms7. 0 earthquake occurred in southwest Longmenshan fault which is the boundary of Qingzang block and South China block. In this study, firstly, using double difference algorithm, the locations of main shock （30.29°N, 102.97°E, 17.82 km） and about more than 4100 aftershocks are obtained. Secondly, using seismic waveforms from GSN/IRIS and Sichuan province digital seismic network the focal mechanisms of the main shock and some aftershocks of Ms〉3.0 are determined. According to the focal mechanism and relocation results, the main shock is a thrust type earthquake, and the strike of the fault plane is 200°. Finally, based on the orientation and slip direction of the fault plane solutions and using mechanism axis tensor method, the direction of the mean stress field is obtained.

关 键 词：芦山地震 余震序列 双差定位 震源机制 平均应力 

分 类 号：P315[天文地球—地震学]