2013年科左后旗5.3级地震前后的P轴转向和应力场变化分析  

P-axis Turning Phenomenon and Stress Field Change before and after the Kezuohouqi M 5.3 Earthquake in 2013

作　　者：李娟[1] 徐岩[1] 韩晓明[1] 张帆[1] LI Juan;XU Yan;HAN Xiaoming;ZHANG Fan(Inner Mongolia Autonomous Region Earthquake Agency,Hohhot 010051,China)

机构地区：[1]内蒙古自治区地震局

出　　处：《华南地震》2019年第S01期97-101,共5页South China Journal of Seismology

基　　金：内蒙古自治区地震局局长基金（2018ZD02）;中国地震局监测、预测、科研三结合课题（170608）;内蒙古自治区地震局局长基金（2019JP02）

摘　　要：为了考察2013年4月22日科左后旗5.3级地震震中区域应力场的中短期变化过程,选取2009年以来发生在开鲁坳陷的ML≥3.0级地震作为研究对象,应用Focmec方法计算了17次地震的震源机制解,根据震源机制解结果绘制的P轴时序分布图显示,在科左后旗地震前,震中区应力场的P轴方位首先表现出中期阶段的"一致性"变化,接着出现短期时段的大幅波动,科左后旗M 5.3级地震则发生在短期显著紊乱过程中,表明开鲁坳陷的P轴趋于一致具有中期指示意义,震前3个月左右出现的P轴大幅度转向具有短期指示意义,科左后旗5.3级地震发生前后,部分余震均表现出与主震较为统一的走滑型机制,压应力轴和张应力轴分别做顺时针和逆时针旋转运动。In order to investigate the stress field variation in the epicenter of the Kezuohouqi M 5.3 earthquake on April 22 nd, 2013, the focal mechanism solutions of the earthquakes with ML≥ 3.0 occurred in Kailu sag since 2009 were calculated by Sonke method. The P axis temporal distribution map showed that, before the Kezuohouqi earthquake, the P-axis azimuth of the stress field in the epicentral region first shows the"consistency" change in the middle stage, then there is a large fluctuation in the short-term period, while the Tongliao M 5.3 earthquake occurs in the process of short-term significant disturbance. The consistency trend of P axis is indicative in the medium term, and the P-axis turning phenomenon about 3 months before the M 5.3 earthquake has a short-term indicative significance. Some of the aftershocks show the same strike-slip mechanism as the main shock. The compressive stress axis and the tension stress axis rotate clockwise and counterclockwise, respectively.

关 键 词：震源机制 科左后旗5.3级地震 P轴转向 应力场 

分 类 号：P31[天文地球—固体地球物理学]