M≥6.0强震后地震序列类型的模糊聚类分析

FUZZY CLUSTERING ANALYSIS ON THE TYPES OF EARTHQUAKE SEQUENCE AFTER A M≥6.0 EARTHQUAKE

摘要:

在充分了解地震序列特征的基础上,选出26项地震序列的原始特征。根据这些原始特征的Wallen评分,精选出11项能突出表现地震序列的特征参数作为指标。采用ISODATA模糊聚类方法对地震序列进行分类,Ⅰ类为M≥6.0强震后三个月内还有震级为M≥5.0的强震发生;Ⅱ类为M≥6.0强震后三个月内无M≥5.0的地震。对中国大陆地区1966年以来的22次M≥6.0强震序列进行聚类分析,建立预报震后趋势判别模型,然后以8次强震序列为例进行了外推检验。结果表明,该方法对地震序列类型的判别效果较好。

Abstract:

Based on the full understanding of characteristics of earthquake sequences,26 items of original features of earthquake sequences are selected from distinct views of physics back-ground. According to the Wallen scores of these original features, 11 items of original fea-tures which can prominently represent the characteristics of earthquake sequences are care-fully chosen as indexes. Using ISODATA method of fuzzy clustering,earthquake sequencesare classified into two categories:Type-Ⅰ sequences are these in which earthquakes with M≥5.0 occur in the same area within 3 months after an earthquake with M≥6.0;Type-Ⅱ sequences are these in which no M≥5.0 earthquakes occur within 3 months.The dis-criminating model of post-earthquake tendency has been built by using 22 known earth-quake sequences occurred in the China continent since 1966. Then, extrapolation tests are taken by using other 8 earthquake sequences occurred in China. The results indicate that this method has good effects on discriminating the type of earthquake sequences.