2017年8月9日新疆精河6.6级地震的震源区域地壳结构和发震断裂几何特征分析

Analysis of Crustal Structure and Seismogenic Fault Geometry in the Focal Region of the Jinghe M6.6 Earthquake in Xinjiang on August 9th, 2017

使用中国地震台网观测报告,选取2017年8月9日新疆精河6.6级地震余震序列的震相数据,应用双差层析成像方法获得震源区域三维地壳速度结构和地震重新定位结果。层析成像结果显示余震序列发生在高低速过渡区,震源区域存在低速层,P波和S波速度在震源区域东南侧低,西北侧高。基于地震重新定位结果,结合高斯牛顿法和模拟退火算法拟合发震断层,分析断层的几何特征,推测发震构造为走向近东西,倾角向南的逆冲断层。

Using the observation report of Chinese Seismic Network,seismic phase data of aftershock sequence of Jinghe M6.6 earthquake in Xinjiang was drawn,and the 3D crustal velocity structure and seismic relocation results are obtained by using the double difference tomography.The results show that the aftershock sequence occurs in the high and low velocity transition zone,and a low velocity layer exists in the source region;the P wave and the S wave velocity are lower in the southeast of the source region,and higher in the northwest side.Based on the results of seismic relocation,combined with Gauss Newton method and simulated annealing algorithm,the geometric characteristics of the seismogenic fault are analyzed.It is inferred that the seismogenic structure is a thrust fault with south dip angle and near east-west direction strike angle.