2009年陕西高陵M_(L)4.8地震震源参数及构造特征分析

Analysis on the Source Parameters and Seismogenic Structures of 2009 Shaanxi Gaoling M_(L)4.8 Earthquake

利用双差定位法对2009-11-05陕西高陵ML4.8地震及其余震序列进行重定位研究,并采用CAP方法求解主震震源机制解,根据所得结果综合分析地震构造特征。结果表明,高陵地震序列主震深度约为6 km,余震主要分布在2~12 km深度范围内,地震序列在平面上呈簇状分布,在深度上大致呈垂直分布;主震震源机制解节面Ⅰ走向103°,倾角61°,滑动角-74°;节面Ⅱ走向252.40°,倾角32.78°,滑动角-116.44°;最佳矩心深度为7 km,矩震级近似为4.2级,P轴方向为北东方向;主震为正断兼少量走滑特征。综合分析认为,渭河断裂与渭南-泾阳断裂交会处为重要的地震潜在地段。

In this study, the aftershocks of Gaoling ML4.8 earthquake occurred on November 5, 2009, in Shaanxi province are relocated by the HypoDD, and the focal mechanism solution of the main shock is determined by the CAP method. Based on the results, we analyze the characteristics of seismogenic structures. The results show that the depth of main shock is about 6 km, and the aftershocks are mainly distributed in the depth range of 2~12 km. Seismic sequences are distributed in clusters on the plane and almost vertical on the depth profile. The focal mechanism solution of the main shock are strike 103°, dip 61° and rake-74°, and strike 252.40°, dip 32.78° and rake-116.44°, respectively. The centroid depth is about 7 km, the moment magnitude is about 4.2, and the P-axis direction is northeast. The focal mechanism results show that the main shock is a normal type earthquake with slightly strike-slip movement. According to the results of relocation and focal mechanism solution, it is suggested that the intersection of Weihe fault and Weinan-Jingyang fault is an important potential seismic area.