爆发余震与强震关系的统计检验

本文按地质构造和地震活动水平,分大华北地区成四个子域.并分析了大华北地区1970——1986年地震目录(其中华北平原子域地震目录为1965——1986年)检测得到爆发余震42次.其中7次发生在强震的余震区,17次发生在震群区.研究其余的18次爆发余震与强震关系,并进行统计检验.结果表明:这18次爆发余震与其后强震发生的随机相遇概率小于6%.用许氏 R 值评分方法估算的爆发余震预报强震的效能大于39%.按照本文给出判定爆发余震的参数,对1987——1988年地震目录进行了外推检验预测.1987——1988年仅有一个爆发余震,即1988年1月6日东北岫岩3.6级地震.它预示1988年1月——1989年1月,东北地区可能有 Ms5.0地震.实际情况是在1988年2月25日,在东北章武地区发生了一次 Ms=5.3地震.另一个实例是在1989年10月18日山西大同——阳高地区发生了一次爆发余震,其后3小时在同一地区也发生了预计的 Ms=6.1地震.以上两例都在实际预报中验证了.爆发余震可能具有一定的预报中强震的能力.

STATISTICAL TESTING OF THE RELATION BETWEEN BURST OF AFTERSHOCKS AND STRONG EARTHQUAKE

According to geological tectonics and seismic activites this paper devided North China ( 30- 45N, 105 - 130E) into four areas. We analized the Nouth China earthquake catalogue from 1970 to 1986 (from 1965 to 1986 for Hua Bei, the North China, plain region) and identified forty- two bursts of aftershock. Seven of them occurred in aftershock regions of strong earthquakes and seventeen of them in the seismic swarm regions. The relation between strong earthquakes with the remaining eighteen bursts of aftershocks has been studied and tested statistically in this paper. The result of statistical testing show that the random probability p of coincidence of bursts of aftershock with subsqeuent strong earthquakes is less than six percent. By Xu's R scoring method the efficacy of predicating strong earthquake from bursts of aftershock is estimated qreater than 39 percent.Following the method proposed in the paper we analyzed the earhtquake catalogue of China from 1987 to 1988-6 The results show that there was only one brust of aftershock occurred on Jan. 6,1988 with M=3.6 in Xiuyan of Northeast China. It implicates that a potential earthquake with Ms 5 might occur in one year afterwards in the region of Northeast China. Actually on Feb.25,1988 an earthquate with Ms= 5.3 occurred in Zhangwu of Northeast China. Another example is Datong-Yanggao shock on October -18, 1989 which is a burst of aftershock. Three hours after an expected shock with M=6.l took place in the same area. Two examples above have been tested in practical predication and this shows that bursts of aftershock are significant in predicating strong earthquakes.