Shear-wave splitting beforeand after the 1999 Xiuyan earthquake in Liaoning, China  

作　　者：太龄雪[1] 高原[1] 曹凤娟[2] 石玉涛[1] 吴晶[1] 焦明若[2] 

机构地区：[1]Institute of Earthquake Science, China Earthquake Administration [2]Earthquake Administration of Liaoning Province

出　　处：《地震学报》2008年第4期340-354,共15页Acta Seismologica Sinica

基　　金：Basis and Special Research Foundation, Institute of Earthquake Science, China Earthquake Administration (2007-24)

摘　　要：Using seismic waveform data recorded at station YK (Yingkou) of Liaoning Telemetry Digital Seismic Network, this paper studied the characteristics of shear-wave splitting before and after the Xiuyan MS5.9 (ML5.3) earthquake in November 29, 1999 with SAM method. The results show that the predominant polarizations of fast shear-waves at YK is in direction of ENE-WSW, consistent with the direction of regional principal compressive stress and also consistent with the direction of the regional tectonic stress field in North China; time-delays increasing before Xiuyan earthquake may shows accumulation of stress before earthquake. The predominant polarizations of fast shear-waves at YK are also related to the spatial distribution of small earthquakes and correlate with the fault strike. The histogram of monthly average polarizations of fast shear-waves shows that polarizations of fast shear-waves also seems to change from two months before the earthquake, but it still needs more data for verification.Using seismic waveform data recorded at station Yingkou （YK） of Li-aoning Telemetry Digital Seismic Network, this paper studied the characteristics of shear-wave splitting before and after the Xiuyan Ms5.9 （ML5.3） earth-quake on November 29, 1999, with the SAM method （Gao et al）. The result shows that predominant polarization of fast shear-waves at YK is in direction of ENE-WSW, consistent with the direction of regional principal compressive stress and also consistent with the direction of regional tectonic stress field in North China. The time-delays increased before the Xiuyan earthquake, indicating stress accumulation before the mainshock. Predominant polarization of fast shear-waves at YK is also related to the spatial distribution of small earthquakes and correlated to the fault strike. The histogram of monthly average polarizations of fast shear-waves shows that the polarization of fast shear-waves seems to have changed from two months before the mainshock, but this needs to be verified with more data.

关 键 词：岫岩地震 剪切波分裂 偏振方向 时间延迟 

分 类 号：P315.31[天文地球—地震学]