赣南地区小震震源机制分析

Analysis on the Focal Mechanism of Small Earthquakes in The Southern Area of Jiangxi

利用从震源向上射出的直达P、S波引起的地动位移振幅比求解震源机制．得到赣南及近邻地区58个M2．0～4．2地震的震源机制解。对震源机制解P、T轴参数进行10°间隔归一频数分析，得到如下结论：①本区地震断层以走滑型为主；②震源机制P轴方位主要分布在270°-330°间，平均方位为287°，P轴倾俯角以小于30°的近水平优势分布．这一结果与区域NWW—SEE水平挤压为特征的构造应力场相吻合。

Based on the amplitude ratios of ground displacement caused by upward direct wave P and S from focal, focal mechanism solutions of 58 ML2.0-4.0 earthquakes in the Southern Area of Jiangxi province and its adjacent areas are calculated. On the basis of analysis by 10° interval normalizational frequence on the parameters of P-axis and T-axis of these focal mechanism solutions, we draw two conclusions： 1 ） the earthquake faults in this area are mainly strike-slip faults; 2） the P-axis orientation are mainly distributed from 270° to 330°,its averaged orientation is 287°, and the P-axis elevation angles are nearly horizontal distribution. The results are consistent with the regional NWW-SEE horizontal compressional tectonic stress field.