W参数及其在华北几次大震的强余震预测中的应用

本文从韦布尔(Weibull)分布λ_(t)=λ_0t~(P-1)出发,推导了表示地震时间序列特征的W参数,并对华北地区1966年邢台(Ms)6.8级,1975年海城(Ms)7.3级和1976年唐山(Ms)7.8级地震的序列资料进行了处理:当W值低于平均水平时可认为是强余震前兆信息的开始;当W值接近或低于警界线σ_时,很可能有强余震发生。W-t曲线与强余震对应结果较好。邢台、海城及唐山强余震的对应结果监定评分分别为:R=0.680,R=0.517及R=0.532,表明用W参数预测华北几次大震的强余震效果是比较显著的。

PARAMETER W AND ITS APPLICATIONS TO THE STRONG AFTERSHOCK PREDICTION OF LARGE EARTHQUAKES IN NORTH CHINA

In the present paper, the parameter W which shows the character ofseismic time sequence is deduced from the Weibull Distribution (λ(t) =λ_o tp~(-1)) and is used to process the data of aftershock sequences of Xing-tai earthquake (M_S=6.8) in 1966, Haicheng earthquake (M_S=7.3) in 1975and Tangshan earthquake (M_s=7.8) in 1976. The results have showedthat the precursor activity of strong aftershocks might begin when the va-lues of the parameter (W) are below the mean (W), and strong aftersho-cks might occur when the values of the parameter (W) are near or belowa warning curve (δ-) on the W-t graph. The curve of W-t is well corresponded with strong aftershocks.