滇西地区中强地震的余震衰减

Attenuation of Aftershock of Moderate-Strong Earthquake in West Yunnan Area

研究了滇西地区 8次中强地震余震序列的衰减特征 ,得出了余震序列频度衰减符合修正的大森定律 :n(t) =k/ (t+c) p 关系 ;余震衰减的快慢与大地热流值成正相关关系 ;强余震前中、小余震活动会出现平静或增强现象 ,即频度残差小于 (平静 )或大于 (增强 )其二倍方差 ,且持续一段时间 ,其后发生强余震的可能性较大。

Attenuation feature of aftershocks for 8 moderate-strong earthquakes in west Yunnan has been analyzed. The results show that the frequency attenuation of aftershock is accorded with the modified 大森Law of n(t)=k/(t+c) p. The speed of aftershock attenuation has positive correlation with geothermal flow. The moderate-small aftershocks before strong aftershock appear quiescence or increasing. That is frequency residual is less than (quiescence) 2 times of mean-square deviation. A strong aftershock is probably to occur afterwards.