摘要:
归纳了自1975年以后华北地区13次中强以上地震的地壳形变短临前兆异常60例。统计地壳形变短临异常与地震的定性关系,发现距震中较远的台站异常出现较早,较近的台站异常出现较晚,地震的震级与异常的空间展布范围成正比,异常往往倾向震中或背向震中。跨断层的位移型形变异常形态有两大类:一类是趋势性异常变化,另一类是高频波动。本文提出了将连续型形变转化为应变的方法。从1989年10月16日大同-阳高61级地震和1991年3月26日大同-阳高5.8缓地震的实例可见,地震往往发生在高应变区或其附近,异常量级可达10-6。
Abstract:
This paper has summarized 60 examples of short term and imminent precursors of crustal deformation of 13 moderately strong and larger earthquakes occurred in North China area since 1995. By statis tics of qualitative relation between short term and imminent anomaKes of crustal deformation and earthquakes, it is found that the anomalies at stations further away from the epicenter occurred earlier, the anomalies nearer to the epicenter occurred later, and the magnitude of earthquakes is directly proportion al to the space distribution of the anomalies. The anomalous shapes of displacement deformation across faults are divided into two types: one type is a tendency anomalous variation, another is a high frequency fluctuation. In this paper, a method has been proposed that the continuous deformati0n is trans formedto strain. From the examples 0f the Datong-Yanggao M6.1 earthquake on October 16, 1989 and the Datong-Yanggao M5-8 earthquake on March 26, 1991, it can be seen that earthquakes of ten occur near the high strain areas, the anomalous quantity can reach 10-6.
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