视应力方法在震群性质判定中的应用研究

利用视应力方法研究了1999～2004年辽宁地区发生的岫岩、 海城、 营口震群性质, 结果显示: 前震序列与其它震群视应力曲线变化形态是完全不同的, 视应力的大小能较好地反映出震源区应力场的大小。 利用视应力数值变化探讨区域震群性质, 与地震活动性参数判定震群性质的方法, 更能反映出每个震群应力场的变化过程, 在原方法不能准确确定震群性质的情况下, 根据应力场的变化过程可以进一步判定震群的性质。 文中还探讨了视应力与震级之间的关系。

Research on the apparent stress method applying to judge the characteristics of earthquake swarm

The swarm characteristics of Xiuyan,Haicheng and Yingkou earthquakes occurred from 1999 to 2004 are studied through apparent stress method in this paper,and the result indicates that the change of apparent stress curves of foreshock sequence is largely different from that of other earthquake swarms.The size of apparent stress can perfectly reflect the size of the stress field in the hypocenter region.Compared to the method of seismicity coefficient judgment,the change of apparent stress of earthquake swarms in the region can best reflect the course of stress change.When the former method is disable to judge the swarm characteristics well and truly,we can still make further study to judge the characteristics through the course of stress change.The relation between apparent stress and magnitude is discussed in the paper.