2014年5月云南盈江两次中强地震震源参数研究

本文采用“剪切-粘贴”(CAP, Cut And Paste)方法, 分别利用区域地震台网的宽频带记录和全球地震台网宽频带记录, 独立反演和联合反演了云南盈江2014年5月24日5.6级和5月30日6.1级地震震源参数。 结果表明, 采用近震和远震数据联合反演结果更为稳定, 5月24日5.6级地震震源机制解两个节面分别为: 走向153°/倾向90°/滑动角171°和243°/81°/0°, 5月30日6.1级地震两个节面分别为172°/72°/180°和82°/90°/-18°。 两次地震断层参数较为接近, 均为走滑型地震, 结合区域构造背景和地震序列重定位结果认为其发震断层可能为近南北向苏典断裂。 震源机制解反演结果与震源区历史地震震源机制解和利用其它方法得到的机制解相近, 也符合震源区的区域应力场特征。 两次地震反演最佳震源深度分别为8 km和6 km, 均为发生在上地壳的浅源地震, 表明苏典断裂在此部位可能并没有切割到地壳深部。

Source Parameters of May 24, 2014 Ms5.6 and May 30, 2014 Ms6.1 Earthquakes in Yingjiang,Yunan Province

Waveforms recorded at local and global seismic networks were adapted to inverse focal mechanism and depth of two moderate earthquakes (May 24, 2014 M_S5.6 and May 30, 2014 M_S6.1) in Yingjiang, China. The new developed Cut-And-Paste method uses two dataset separately and simultaneously. Both two earthquakes are right lateral strike slip event. The fault plane of the M_S5.6 event is 153°/90°/171°while the M_S6.1 event is 172°/72°/180. These fault planes are consistent with local stress field. The focal depth results are much shallower than results with global average model. With the distribution of aftershock and other previous results, the Sudian fault, which is a north-south fault, is the possible seismogenic fault.