云南及其邻近地区地震活动的模式识别

本文用模式识别方法(CORA—3修改方法)研究了云南及其邻近地区大地震的发生时间与中强地震活动特性的关系。结果表明(不分子集):M≥7.0级大震前1—2年内,5—5.9级地震频度有明显增强。前1年6—6.9级地震相对减弱,前2—4年内6—6.9级地震可增至一定水平。对于CORA—3修改算法在采用“CLUSTERS”算法和不用“CLUSTERS”算法所得识别分类结果基本一致。FH(future history test)试验表明,用1930—1986年为学习时段,1969—1986年为预测时段。得到D类识别率为0.6,N类误识率为0.38。

RECOGNITION OF SEISMICITY PATTERNS FOR YUNNAN AND ITS NEIGHBORING REGIONS

Using the pattern recognition method (the modified CORA-3 method), this paper studies the relationships between occurrence time of strong shocks find seismicity features of moderately-strong events for Yunnan Province and its neighboring regions. Result of our study shows (the subaggregates not divided) : Frequency of M5-M5.9 events clearly became greater 1 - 2 years before occurrences of M7.0 shocks. Number of M6-M6.9 events relatively dropped 1 year before the occurrences of M7.0 shocks, whereas number of M6-M6.9 events may increase to a certain level within 2-6 years before the strong M7.0 shocks. When the modified CORA-3 method is adopted, basically similar resulte could be obtained no matter using or not using the "cluster" calculations. The FH (future history) test suggests a recognition rate of 0.6 for class D events whereas a false-recognition rate of 0.38 for class N events if using a studied time span of 1930-1986 and a prediction time span of 1969 - 1986.