滇西地区前兆震群参数的主成分分析

Principal Component Analysis for the Precursor Swarm Parameter in West Yunnan, China

对1970年以来滇西地区中小地震资料进行了分析,给出了滇西地区震群及前兆震群的定义;应用主成分分析方法构建了前兆震群判别方程,对震群活动的异常特征进行了分析。结果表明,滇西地区前兆震群具有集中分布的区域特征,主要分布在洱源、剑川、宁蒗、龙陵、腾冲、梁河一带。滇西地区前兆震群综合预报方案以P≥0.42为阈值,前兆震群出现后,2年内发生M≥5地震的对应率达到88%。

Through analyzing and processing the data of the small earthquakes in West Yunnan since 1970, the definitions of the earthquake swarm and the precursor swarm in the area have been given. The anomalous characteristic of the swarm activity is analyzed using the precursor swarm distinguishing equation constructed by the principal component analysis method. The results show that the precursor swarms in West Yunnan have the regional feature of concentrating distribution, mainly along the areas of Eryuan, Jianchuan, Ninglang, Longling, Tengchong and Lianghe. The comprehensive prediction project of the precursor swarms in West Yunnan takes the P≥0. 42 as threshold value, by which the corresponding ratio of M≥5 earthquakes reaches 88% around the distinguished precursor swarms in the following two years.