赣北地区中小地震震源机制分析

Analysis on the focal mechanism of medium-small earthquakes in the northern area of Jiangxi Province

利用Snoke方法计算赣北地区2008—2015年11个M_L≥3.0中小地震震源机制。结果表明,其P轴和T轴方向与该区域构造应力场基本一致。赣北地区以近EW向挤压、近NS向拉张的构造应力为主。区域内断层错综复杂,以走滑、正断型为主。其中九江—瑞昌地区受襄樊—广济断裂、郯庐断裂相互作用,在方向稳定的构造应力作用下,易发生走滑型为主的地震。

Using the method of Snoke, focal mechanism solution for 11 medium-small earthquakes with M_L≥ 3.0 were calculated in northern area of Jiangxi Province since 2008 to 2015. The result showed that P axis and T axis accorded with tectonic stress field in this area. In the northern area of Jiangxi Province, tectonic stress field was composed by compressive stress in EW direction and tensile stress in NS direction. Fault zones were dominated by strike-slip fault and normal fault. Jiujiang-Ruichang area was controlled by Xiangfan-Guangji fault zone and Tanlu fault zone, it was easy to take the strike-slip earthquakes under tectonic stress field with stability direction.