江苏射阳地区地震尾波Qc值特征

Characteristics of seismic coda Qc value in Sheyang region,Jiangsu Province

选取2009—2018年江苏省射阳地震台200 km范围内M_(L)≥2.0地震波形资料,基于Sato单次散射模型,计算该区域S波尾波Qc值,并探求其时间变化特征。采用相同方法计算盐城、灌云地震台地震波形资料尾波Qc值,并将3个地震台的计算结果进行对比。结果表明:射阳地区是江苏省尾波Q0低值区域,Qc值随频率的变化关系为Qc(f)=33.7±3.4f^(1.16±0.04);在2016年10月20日射阳M_(L)4.8地震前,射阳地区尾波Qc值有增大现象,Qc值变化特征表现为上升—下降—上升—发震;盐城、射阳、灌云地震台所记录地震的尾波Qc值在震前均出现明显的高值异常变化。

Based on the single scattering model (Sato), S-wave coda Qc values are calculated using a fixedelapsed time of 30 s for seismic waveforms recorded at the Sheyang seismic station in JiangsuProvince for M_(L) ≥ 2.0 earthquakes that occurred from 2009 to 2018 and located within 200 km,and their temporal variation characteristics are explored. By the same method, coda Qc values forYancheng and Guanyun seismic stations are calculated and the results of the three seismic stationsare compared. The results show that the sheyang area is a relatively low coda Q0 region and therelation between Qc value and frequency is Qc( f ) = 33.7±3.4f ^(1.16±0.04). Before the Sheyang M_(L) 4.8earthquake on October 20, 2016, the value of coda Qc increased in the Sheyang area. The variationpattern of coda Qc value is up-down-up before the earthquake. The coda Qc values at Yancheng,Sheyang and Guanyun seismic stations all showed obvious high-value abnormal changes beforethe earthquake.