震级频度关系非线性偏离度及其意义-以京西北及大同地区为例

NONLINEAR DEVIATION OF THE FREQUENCY-MAGNITUDE DISTRIBUTION AND ITS SIGNIFICANCE-TAKING NORTH-WEST BEIJING AND DATONG AREA AS EXAMPLES

摘要: 大量地震资料统计发现古登堡一里克特公式Lg(N)=a-bM中震级频度关系是非线性的,在3-4级间往往发生转折。设高震级段和低震级段的斜率分别为Bh和B1,其间夹角α称为非线性偏离度,并设Bh>B1时,α为负,否则为正。对京西北及大同地区震级频度关系非线性偏离度进行时空扫描后发现大震前α值有正向增大倾向。

Abstract: It is known that the Frequency Magnitude relationship in Gutenberg-Richter law, lg(N)=A-B·M, is nonlinear based on the statistics by using seimological catalogue.A turning isusually occurred in magnitude of 3 to 4.Call the slope of the higher segment in Frequency Magnitude relationship as Bh, the lower as Bl and the angle between them as a-the Non-linear Deviation.And suppose a is negative when Bh>Bl, elso is positive.A positive devia-tion before strong earthquakes was found by the time-space scanning of a in North West Bei-jing and Datong area.