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本文利用云南姚安MS6 5地震后在震中附近架设的 3个三分向数字记录台站的地震资料 ,对该区S波分裂进行研究。结果表明 :① 2 36条处于横波窗内的记录S波分裂现象明显 ;②延迟时间大部份在 3 5～ 10 5ms km范围 ,平均值为 7 0ms km ;③快波偏振方向大部份在N140°E～N16 4°E范围 ,平均值为N15 2 4°E ;④快波的优势偏振方向与主震的发震断裂 (马尾菁断裂 )和余震的发震破裂方向不一致 ,而与该区的主压应力方向比较符合 ;⑤姚安地震余震序列的S波分裂是应力场控制的EDA裂隙各向异性的结果。
In this paper, we use the seismic data of three tristimulus stations set up near the epicenter after Yao’an MS6 5 earthquake in Yunnan Province to study the S-wave splitting in this area. The results show that: (1) There are obvious signs of S wave splitting in 2 to 36 transversal wave windows; (2) the delay time is mostly in the range of 35 km-105 ms km and the average value is 7 km km; (3) N140 ° E ~ N16 4 ° E, and the average is N15 2 4 ° E. ④ The dominant polarization direction of fast wave is inconsistent with the seismogenic rupture of aftershocks and mainshock faults (mawei cyanine fracture) The main compressive stress direction of the area is in good agreement. (5) The S-wave splitting of aftershock sequence of Yao’an earthquake is the result of EDA fracture anisotropy controlled by stress field.