寻乌及邻区震源机制和视应力特征

利用寻乌及邻区2009年以来的地震波形资料，采用Snoke方法反演19次ML2.5以上地震的震源机制，计算89次ML1.5以上地震的视应力。结果显示，寻乌及邻区的走滑型地震占绝对优势，震源机制解P轴优势方向分布在310°~320°和110°~130°之间，倾角绝大多数在40°以内，与该区以NWW-SEE向水平挤压为特征的构造应力场吻合；寻乌震群集中区内8次ML2.5以上地震的震源机制结果一致性较好。寻乌及邻区视应力与震级呈正相关，2017-11-06寻乌ML3.8震群前的差视应力值出现高值波动。

Characteristics of Focal Mechanisms and Apparent Stress in Xunwu and Its Adjacent Area

The focal mechanism solutions of 19 ML≥2.5 earthquakes in Xunwu and its adjacent areas are inversed using the Snoke method and seismic waveform data since 2009, and the apparent stress of 89 ML≥2.5 earthquakes are calculated. The results show that strike-slip earthquakes are dominant in Xunwu and its adjacent areas, the dominant directions of P axis of focal mechanism solution are 310°~320°, 110°~130°, and the dip angles are mostly within 40°, which is consistent with the regional NWW-SEE horizontal compressional tectonic stress field. The focal mechanism solution of 8 ML≥2.5 earthquakes in Xunwu earthquake cluster area are in good agreement. The apparent stress is positively correlated with magnitude, and there is a high value fluctuation of apparent stress before the Xunwu ML3.8 earthquake group event on November 6, 2017.