江苏射阳地区地震尾波Q_c值特征

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Q_c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Q_c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Q_0低值区域,Q_c值随频率的变化关系为Q_c(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Q_c值有增大现象,Q_c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Q_c值在震前均出现明显的高值异常变化。

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

Based on the single scattering model (Sato), S-wave coda Q_c values are calculated using a fixed elapsed time of 30 s for seismic waveforms recorded at the Sheyang seismic station in Jiangsu Province 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 Q_c values for Yancheng and Guanyun seismic stations are calculated and the results of the three seismic stations are compared. The results show that the sheyang area is a relatively low coda Q₀ region and the relation between Q_c value and frequency is Q_c(f)=33.7±3.4f ^1.16±0.04. Before the Sheyang M_L 4.8 earthquake on October 20, 2016, the value of coda Q_c increased in the Sheyang area. The variation pattern of coda Q_c value is up-down-up before the earthquake. The coda Q_c values at Yancheng, Sheyang and Guanyun seismic stations all showed obvious high-value abnormal changes before the earthquake.