灯塔5.1级地震Lg波Q值变化特征

Variation Characteristics of Lg wave Q value of Dengta M5.1 Earthquake

本文基于Lg谱比法的地震衰减参数与台站场地响应联合反演方法,利用2010—2014年辽宁台网记录的ML≥2.5地震观测资料,反演计算2013年1月23日灯塔5.1级地震前后的Lg波Q值和频率依赖指数η的变化,结果发现灯塔地震区介质的Lg波衰减Q和η在地震前后有明显的变化,且变化趋势相反。Q值在震前整体呈上升的趋势,上升中有小幅的下降,震后有下降恢复的趋势,而地震波衰减特征在区域内表现出对频率较强的依赖。

In this paper,using the joint inversion method of seismic attenuation parameters and station site response based on Lg spectral ratio method,we get the variation of the Lg wave Q and frequency dependence indexηvalue before and after the Dengta 5.1 earthquake on July 23,2013 from the M_(L)≥2.5 seismic observation data recorded by Liaoning network from 2008 to 2014.The results show that the attenuation Q andηof Lg wave are changed obviously and their variation tendency is opposite before and after the earthquake.Q value shows an overall upward trend before the earthquake,with a slight downward trend halfway and then went down to recovery after the earthquake,while seismic wave attenuation characteristics show strong dependence on frequency in the region.