苍山5.2Ms级地震前后地震前兆综合危险度的变化

CHANGE OF SYNTHETICAL RISK DEGREE OF SEISMIC PRECURSORS BEFORE AND AFTER THE M5 2 CHANGSHAN EARTHQUAKE

地震前兆综合危险度是以系统论为基础的一种综合地震预报的新方法。利用山东省每年年底的地震会商报告给出的地震前兆异常，而不是取震后的震例总结或论文给出的异常，通过“专家系统”的思想，对每一异常事件进行综合评估，计算出无量纲的、归一化的地震前兆综合危险度，分析了１９９５年９月２０日山东苍山５２Ｍｓ级地震前综合危险度的变化特征。震前综合危险度出现了一次明显的高值异常变化，震后危险度很快下降恢复到正常水平。

The synthetical risk degree of earthquake precursors is a new method of synthetical earthquake prediction based on systematic theory. Using the precursor anomalies selected from seismic consultaion reports at the end of each year instead of from the earthquake case summarization after earthquake, synthetical evaluation for every precursor event is made by the“specialist system”;non-dimensional synthetical risk degree of earthquake precursors with normalized value is calculated and the variation characteristics of the synthetical risk degree before the Ms 5 2 Changshan earthquake of Sept. 20, 1995 are analyzed. Obvious increase in the synthetical risk degree occurred before the earthquake, and after the earthquake, the risk degree rapidly recovered to the normal level.