2017年8月9日精河6.6级地震序列重定位与发震构造初步研究

Relocation of the Jinghe M_S6.6 earthquake sequence on August 9,2017 and analysis of the seismogenic structure

基于新疆区域数字地震台网震相观测报告,采用HypoDD方法精确定位了精河M_S6.6地震序列ML≥1.0地震的震源位置,综合分析了此次地震序列的空间分布特征和可能的发震构造。结果显示,主震震中为44.2639°N、82.8294°E,震源初始破裂深度为17.6km;地震序列总体沿近EW(273°)向单侧扩展,展布长度约20km;震源深度优势分布范围为7~17km;沿余震走向的深度剖面显示,主震向西10km范围内,余震震源有逐渐变浅的趋势,余震序列中尾端向SW方向偏转的地震震源较深;垂直于地震序列的深度剖面显示,地震序列自北向南呈现逐渐加深的变化特征,表明发震断层面倾向为S倾。综合考虑中国地震局地球物理研究所给定的震源机制解以及震源区地质构造情况推测,精河M_S6.6地震发震构造可能为库松木契克山前断裂东段。

Based on the waveforms of Xinjiang Digital Seismic Network,the Jinghe M_S6.6 earthquake sequence（ ML≥ 1.0） were relocated by HypoDD. The characteristics of the spatial distribution and the seismogenic structure of this earthquake sequences were analyzed. The results show that the main shock was relocated at 44.2639° N,82.8294° E,the initial rupture depth was 17.6 km. The earthquake sequence clearly demonstrated a unilateral extension about 20 km nearly in the EW direction,and were mainly located in the depth of 7 ~ 17 km. The depth profile of the aftershocks shows that the focal depth of the aftershocks tended to be shallower within 10 km to the west of the main shock,and the depth of the seismic source in the tail direction of the aftershock sequence to SW direction was deeper. The depth profile perpendicular to the earthquake sequence shows that the seismic sequence was gradually deepened from north to south,which indicates that the fault plane was dipping south. According to the focal mechanism solution provided by the Institute of Geophysics,China Earthquake Administration,and the geological structure in the source region,it is inferred that the seismogenic structure of the Jinghe earthquake with M_S6.6 may be the eastern segment of the Kusongmuxieke fault.