新疆北天山地区中强震前单台地震波参数异常特征研究

STUDY ON THE FEATURES OF SINGLE STATION SEISMIC WAVE PARAMETER ANOMALIES BEFORE MODERATE, STRONG EARTHQUAKES IN NORTH TIANSHAN,XINJIANG

强地震的孕育过程也是孕震介质的形成过程。在强震前震源附近小地震的地震波运动学、动力学特征的变化过程，则反映了孕震介质的变化过程。为研究地震的孕育、发展和发生的过程，采用单台地震波振幅比、尾波持续时间比、尾波衰减系数这３ 项地震波参数作为地震学短期前兆指标，分析其震兆特征，从而达到监测孕震介质变化的目的。研究结果表明：单台地震波参数能够有效地发现地震的前兆，但地震波参数的前兆图像复杂多变，不具有统一的变化模式，由简单到复杂，整体的“由白变花”为其最本质的震兆特征。在研究中使用计算机对地震波参数进行了长期连续的时空扫描，分析了异常特征，客观地评估了它的预报效能。

The process of strong earthquakes developing is also the process of seismogenic medium forming. The varying process of seismogenic medium can be reflected by the varying process of the kinetic,dynamic features of seismic waves of minor shocks near the source before a strong earthquake.In order to study the process of earthquake development and occurrence,3 seismic wave parameters:seismic wave amplitude ratio,coda duration ratio,coda decay coefficient,are taken as short term precursory indexes of earthquakes to analyze the features of earthquake precursors,thereby to monitor the variation of seismogenic medium. The research result shows: Seismic precursors can be effectively found in single station seismic wave parameters.but the precursory patterns of seismic wave parameters are complicated and various,without a united varying model.That the patterns vary from simplicity to complication,from white to variegation as a whole is the most essential features of earthquake precursors.In the research,the seismic wave parameters are scanned in time and space in a long time using computer so as to analyze their anomalous features,and the prediction ability of seismic wave parameters is evaluated.