青藏高原东缘地震波数字资料几种振幅比的前兆测定

根据兰州数字遥测地震台网记录的祁连山中东段的地震资料,利用近震的几种体波及地震波初动的3种振幅比:尾波振幅比、纵波与横波振幅比、初动纵波与横波最大振幅的振幅比的4个振幅比参数rco、Rco、Sco1、Sco2,对该区的2000年6月6日景泰MS5.9地震、2001年7月11日肃南MS5.3地震和2000年9月12日兴海MS6.6地震及余震群进行分析研究。结果表明中强震前各类振幅比会出现高值异常,振幅比参数出现异常后大部分大约1~4个月发震。振幅比参数Sco1、Sco2对应地震关系更明显,说明初动纵波的振幅比由于最先到达,它不受其他波迭加的干扰,能较好的反映孕震区的信息。

Some Amplitude Ratio Precursors from Data of Digital Seismic Waveform in East Margin Area of Qinghai-Tibet Plateau

Based on the data of Lanzhou digital telemetry seismic network(Lanzhou DTSN),using four parameters(rco,Rco,Sco1,Sco2) from three amplitude ratios among some body waves and first motion of seismic wave,which are amplitude ratio of end portion in the wave,amplitude ratio of P and S waves,and amplitude ratio of first motion of P wave and the maximum amplitude of S wave,the anomolies before Jingtai earthquake(M_S5.9) on June 6,2000,Sunan earthquake(M_S(5.3)) on July 11,2001,and Xinghai earthquake(M_S6.6) are analyzed and researched.The result shows that each type of amplitude ratio appears high value better moderate-strong earthquakes in 1~4 months,among them parameter Sco1 and Sco2 have better relation with earthquake.That means,because the frist motion of P wave arrives station first and is not disturbed by other waves,the amplitude ratio of it cna reflect the information of seismogenic region directly.