利用不同速度模型反演越西M_S5.2地震震源机制解及震源深度  

Inversing the focal mechanism and the focal depth of Yuexi M_S5.2 earthquake using the different velocity model

作　　者：魏娅玲[1] 黄雪影[1] 

机构地区：[1]四川省地震局,中国成都610041

出　　处：《地震地磁观测与研究》2016年第1期38-44,共7页Seismological and Geomagnetic Observation and Research

基　　金：中国地震局测震台网青年骨干培养专项(专题编号:20140320)

摘　　要：为了解不同速度模型对四川越西MS 5.2地震震源机制解及震源深度结果的影响,我们使用四川和云南测震台网宽频带数字地震波形,采用CAP方法和3种不同速度模型进行波形反演,结果显示:1 3种模型获得的台站波形拟合互相关系数均大于61%,且地震震源机制解参数基本一致,结果稳定、可靠;2反演得到越西地震的矩震级为MW 5.03,震源深度为10 km,断层节面Ⅰ走向355°、倾角81°、滑动角29°,节面Ⅱ走向260°、倾角61°、滑动角170°,P轴方位角124°、仰角14°,T轴方位角221°、仰角27°,该地震断层属于左旋走滑型;3推断此次地震活动是大凉山断裂左旋走滑错动结果。In order to understand the influences of different velocity model in the inversion result of the Sichuan Yuexi MS 5.2 earthquake focal mechanism and focal depth, we perform seismic waveform inversion with the Sichuan and Yunnan Provinces seismic network wideband digital seismic waveform and CAP method, adopting the three different velocity models, respectively. The result showed： 1 Using three velocity model, the correlation coefficients of waveform fitness for all stations are larger than 61%, and inversion results are consistent well, they are stable and reliable. The waveform fitting relationship coefficient of the model B is the largest, the model should be more suitable for the west region in Sichuan Yuexi region. 2 The moment magnitude was MW 5.03. The earthquake focal depth is 10 km. The strike angle, dip angle, and slip angle are 355°, 81°, and 29°, respectively, for the one nodal plane. The strike angle, dip angle and slip angle are 260°, 61° and 170°, respectively, for another nodal plane. The azimuth angle and elevation angle are 124° and 14°, respectively, for P axis. The azimuth angle and elevation angle are 221°, 27°, respectively, for T axis. The results indicate that the fault belongs to sinistral strikeslip type. 3 The one nodal plane parameters accord with big Liangshan fault attitude near the epicenter. Principal compressive stress direction and regional stress direction is consistent. So that,the result indicates that this earthquake activity is due to the sinistral strike-slip movement of big Liangshan fault.

关 键 词：CRUST 2.0速度模型 CAP方法 震源机制解 震源深度 

分 类 号：P315.33[天文地球—地震学]