2017年九寨沟MS 7.0地震震源深度测定  

Determination of the depth of 2017 Jiuzhaigou M_S 7.0 earthquake in Sichuan with a variety of methods

作　　者：郑国栋[1] 梁姗姗[2] 邹立晔[2] 梁建宏[2] 徐志国[3] 安祥宇[4] Zheng Guodong;Liang Shanshan;Zou Liye;Liang Jianhong;Xu Zhiguo;An Xiangyu(Jilin Earthquake Agency,Changchun 130022,China;China Earthquake Networks Center,Beijing 100045,China;National Marine Environmental Forecasting Center,Beijing 100081,China;Liaoning Earthquake Agency,Shenyang 110034,China)

机构地区：[1]吉林省地震局,中国长春130022 [2]中国地震台网中心,中国北京100045 [3]国家海洋环境预报中心,中国北京100081 [4]辽宁省地震局,中国沈阳110034

出　　处：《地震地磁观测与研究》2019年第5期21-28,共8页Seismological and Geomagnetic Observation and Research

基　　金：中国地震局地震科技星火计划(项目编号:XH19053);中国地震局经常性项目“国家自动速报中心(CSN/GSN)运维及系统优化”

摘　　要：为了更好地确定2017年8月8日九寨沟MS 7.0地震震源深度其发震机理,利用四川、甘肃和青海区域地震台网的观测波形数据,采用多种方法研究了此次地震的震源深度。首先,采用gCAP方法反演了九寨沟MS 7.0地震的震源机制解和矩心深度,结果显示,节面Ⅰ走向243°/倾角87°/滑动角-158°,节面Ⅱ走向151°/倾角68°/滑动角-3°,矩震级为MW 6.5,矩心深度为8 km;然后,采用ISOLA近震全波形方法反演了此次地震的震源机制解,反演结果与gCAP方法结果相差不大,矩心深度为7 km;最后,通过sPn震相与Pn震相之间的走时差测定此次地震初始破裂震源深度,结果显示深度约为12 km。研究表明,九寨沟MS 7.0地震的矩心深度为7—8 km,初始破裂深度约为12 km。In order to better understand the depth and its mechanism of the 2017 Jiuzhaigou MS 7.0 earthquake in Sichuan,we take different methods to study the centroid depth of this earthquake using the waveform data from the Sichuan,Gansu and Qinghai network.First,we invert the focal mechanism to get the centroid depth of the Jiuzhaigou MS 7.0 earthquake.The result shows the best double-couple solutions as follows:The strike,dip and rake for the first nodal plane are 243°,87°,-158°and 151°,68°,-3°for the second nodal plane respectively with the moment magnitude 6.5 and the centroid depth 8 km.Subsequently,we use ISOLA local earthquake full waveform inversion method to determine the focal mechanism of this earthquake,which is similar to the results from gCAP with the centroid depth 7 km.Finally,we use the time difference between sPn and Pn phases to determine the initial rupture depth of the Jiuzhaigou MS 7.0 earthquake on August 8,2017 in Sichuan and the results show that the focal depth is about 12 km.The research shows that the centroid depth of the Jiuzhaigou earthquake is 7—8 km and the initial rupture depth is about 12 km.

关 键 词：九寨沟MS 7.0地震 震源深度 gCAP方法 ISOLA方法 SPN震相 

分 类 号：P31[天文地球—固体地球物理学]