摘要
本文较系统地分析了近十几年来我国45次中强震(5级左右31次,6级以上14次)前后数年内震中区附近基准地磁台地磁特征线参数(斜率K,相关系数C,或然误差γ)随时间的变化。在正常情下,参数在临界值(k=-0.16,c=0.75,r=1.8)以内变化,即k>-0.16、c<0.75、γ<1.8。但在震前两三个月内,k、c、γ随时间的变化曲线同时超出临界值,出现k值下降,c值上升的对偶异常。用上述参数组预报地震的显著优点是降低了虚报率,除了内符检验较好外,在用于预报地震中也取得了实效。本文还给出了参数的异常幅度k与震中距L,震级Ms与震中距L之间的经验关系式。k=aL+b;Ms=EL+D。地磁特征线法用于地震预报的物理意义已有文献报导。近年来通过大量震例分析和预报实践,在提炼该方法的定量预报指标,提高报准率,降低虚报率等方面作了进一步的探讨。
This paper deals with the variations of parameters of geomagnetic characteristic line at the reference geomagnetic stations which are close to some epicenters of strong earthquakes, 45 strong earthquakes(31 earthquakes of M=5 and 14 of M≥6)occurred in the last twenty odd years are refered and the parameters including k, the slop of the characteristic, and c, the correlation coefficient, as well as r, the standard error, are used in this paper. Geenrally speaking, the parameters vary within critical v lllue(k, -0.16, c: 0.75, r: 1.8)but in two or three months prior to earthquakes, there seems to have variations in k, c and r, exceeding the critical values mentioned above, and the variations show a so-called coupled anomaly, i. e. an increase in c and a decrease in k. One of the obvious advantages by using the parameters combination in prediction is that the percentage of false forecast has been decreased. Besides the internal symbol test is better, the actual result in trial prediction of earthquakes has been achieved.
出处
《华北地震科学》
北大核心
1990年第4期99-108,共10页
North China Earthquake Sciences
