摘要
利用四川地震台网记录到的宽频带数字波形,采用P波初动法,对发生在2016年5月29日安县和6月27日北川两次四级地震进行了计算,得到的震源机制解结果。两次地震均属于右旋走滑型地震,发震断层面分别为南北和北东走向,与龙门山断裂带走向基本一致,滑动角都接近水平,倾角近90°,说明该区域断层面较为陡峭,两起地震的主压应力轴方向都为北西西向,与龙门山地区构造应力场的主压应力方向一致,说明震源应力场主要受龙门山区域应力场的影响。
Using the broadband seismic wave data of Sichuan seismic network,we calculate the focal mechanism solution of two M4. 0 earthquakes in 2016 by P wave polarity method. According the focal mechanism result,two earthquakes are caused by dextral strike-slip. The directions of seismogenic fault are NS and NE in accordance with the Longmenshan fault strike. The rake near horizontal and dip near vertical and which means the local fault is abrupt. The principal compressive stress axis is NWW trend,in accordance with the tectonic stress field of Longmenshan area,which means these two earthquakes are influenced by local stress field.
出处
《四川地震》
2017年第3期30-32,共3页
Earthquake Research in Sichuan
关键词
震源机制
应力场
P波初动
龙门山断裂带
focal mechanism
tectonic stress field
P wave polarity
Longmenshan fault
