中强地震前地震波参数异常的研究

STUDY ON THE PARAMETER ANOMALY OF SEISMIC WAVE BEFORE MODERATELY STRONG EARTHQUAKES

本文研究了1988年5月26日库尔勒M_35.5地震和1991年2月25日柯坪M_s6.5地震前后的地震波初动符号、振幅比、尾波持续时间比和尾波衰减系数的变化特征,发现两次地震前上述参数均具有不同程度的异常。地震前(?)波初动一致性越强,持续时间越长,未来地震震级越大;振幅比突跳是即将发生地震的明显信号;首先出现尾波衰减系数异常的台站距未来地震震中较近。根据上述参数的异常特征,成功地预报了1991年6月6日和静M_s5.2地震。

This paper studies the change features of onset sign of seismic wave, amplitude ratio, duration time ratio of coda, and attenuation coefficient of coda before and after the Kuerle Ms 5.2 earthquake on May 26. 1988, the KepingMs6. 5 earthquake on Feb. 25, 1991. It is found that before the two earthquakes the parameters above—mentioned are of anomalies in various degrees. Before the earthquakes, the stronger the coincidence of P wave onset is, the longer the duration time is. the larger the magnitude of coming earthquake is; the sudden jump of amplitude ratio is the obvious sign of earthquake that will occur soon; the station in whith the anomaly of attenuation coefficient of coda first appears is close to the epicenter of coming earthquake. Based on the anomaly features of the parameters, we have successfully predicted the Hejing Ms5. 2 earthquake on June 6,1991.