摘要
采用Hypo2000和双差定位方法对2013年云南洱源MS5.5和MS5.0地震序列进行了重新定位.结果显示:精定位后洱源地震序列分布优势方向集中在160°;用CAP方法反演了两次5级地震震源机制,节面Ⅱ的走向158°和157°与余震优势分布方向一致;现场考察MS5.5和MS5.0地震极震区的长轴方向也是NW向.上述结果与维西—乔后断裂NNW走向一致,据此判定该断裂为洱源MS5.5和MS5.0地震的发震构造.序列震源机制解显示,洱源地震序列表现出不同的错断性质以及不同方向主压应力,可能与维西—乔后断裂所处区域复杂构造应力场有关.
The Eryuan MS 5.5 and MS 5.0 earthquake sequence are relocated by using absolute location （Hypo2000 ）and double-difference earthquake location （HypoDD）methods.The results show that the dominant direction of relocated aftershocks concentrated at 160°.Focal mechanisms of the MS 5.5 and MS 5.0 earthquakes are inverted by CAP method.The inversion result shows that the strike angles of the nodal plane Ⅱ were 158°and 157°,respectively,which are consistent with dominant distribution direction of aftershocks.Field survey sug-gests that the major axis of the meizoseismal region was also in NW direction. The above three directions were consistent with the NNW strike orientation of Weixi--Qiaohou fault,which can be considered as the seismogenic structure of the Eryuan earthquake sequence.Focal mechanisms of the sequence indicate that different focal dislocations and different orientations of principal compres-sion stresses,may have relationship with the complex regional structural stress field of Weixi--Qiaohou fault.
出处
《地震学报》
CSCD
北大核心
2014年第4期640-650,2,共11页
Acta Seismologica Sinica
基金
国家"十二五"科技支撑计划项目(2012BAK19B01-07)资助
关键词
洱源地震序列
精确定位
震源机制
维西-乔后断裂
Eryuan earthquake sequence
accurate location
focal mechanism
Weixi--Qiaohou fault
