永胜6.0级地震的余震S波分裂研究  

Shear Wave Splitting of Aftershocks of M6.0 Yongsheng Earthquake

作　　者：邬成栋[1] 秦嘉政[1] 皇甫岗[1] 

机构地区：[1]云南省地震局,昆明650041

出　　处：《地震研究》2004年第2期140-145,共6页Journal of Seismological Research

基　　金：云南省重点科技攻关项目<云南强震中短期预测研究>资助 (课题编号 :2 0 0 1NG46) .

摘　　要：利用云南永胜 6 0级地震的余震资料对该区S波分裂进行了研究。结果表明 ,快速横波偏振方向有两个优势取向 :N2 0°W和N6 0°W ,前者与区域主压应力方向一致 ,后者则为永胜地震主破裂方向。可以认为 ,永胜地震的S波分裂是应力作用的EDA裂隙与发震破裂隙共同作用的结果。延迟时间在 2～ 2 0ms km范围内变化 ,整个时段的平均值为 7 0ms km。与以前许多学者的研究结果比较 。A study of the Shear wave splitting wave is made through the recordings of aftershock of M6 0 Yongsheng earthquake occurred in Yunnan Province in 2001.The results show that the shear wave has two preponderant polarizations.One is N20°W oriented and another is N60°W oriented.The former is in accordance with the regional predominant direction of principal compressive stress and the latter is the direction of the fracture of main shock.So, the joint effect of EDA fracture and the seismogenic crack can be regarded as the cause of the shear wave splitting of Yongsheng Earthquake.The time delay of shear wave splitting from 2 ms/km to 20ms/km and the average of the whole process is 7 0ms/km.The result is in very good accordance with the result got by the forerunners.

关 键 词：余震 S波分裂 各向异性 裂隙作用 永胜地震 

分 类 号：P315.3[天文地球—地震学]