2016年5月22日辽宁朝阳4.6级地震震源机制和震源深度研究

摘要

2016年5月22日17时08分,辽宁朝阳县发生M4.6地震.本文利用P波初动、TDMT、CAP等方法研究该地震的震源机制解,利用CAP、PTD、sPn-Pn等方法测定震源深度.结果表明,3种方法计算震源机制解所得结果一致,CAP、PTD、sPn-Pn等方法测定的深度结果接近.利用双差定位法对2009～2016年发生在震源区域的地震重新定位,结合模拟退火算法和高斯牛顿算法拟合得到小地震分布的走向和倾角.根据震源机制解、震源深度、小地震分布特征和震源区域的构造特征等判断,发震构造断裂走向为NEE,倾角接近垂直,主压应力方向为NNW向,震源机制为正断类型,并带有较小的左旋分量.%An earthquake with Ms4.6 occurred at 17 ∶ 08,May 22,2016 in Chaoyang,Liaoning.We used the P-wave first motion method,TDMT method,and CAP method to determine the focal mechanisms and the PTD method and sPn-Pn method to determine the focal depth.The focal mechanism results of the three methods are consistent.The depth results of the CAP method,PTD method and sPn-Pn method are close.We used the double difference location method to relocate earthquakes in 2009-2016,and obtained the strikes and dip angles of the small earthquake distributions with the help of simulated annealing algorithm and gauss Newton algorithm fitting.According to the focal mechanism results,the depth results,the characteristics of small earthquake distributions and the structural characteristics of the source area,the seismogenic fault strike is NEE and the main pressure force direction is NNW.The earthquake focal mechanism is for normal fault type with a little left-lateral strike slip motion.