低纬度环球带和环太平洋带大地震的幕式活动分析  

An analysis on episodes of great earthquakes in the low-latitude circum-earth zone and circum Pacific zone

作　　者：杜品仁[1] 马宗晋[1] 高祥林[1] 赵俊猛[2] 

机构地区：[1]中国地震局地质研究所,北京100029 [2]中国科学院青藏高原研究所,北京100085

出　　处：《地球物理学报》2010年第12期2869-2874,共6页Chinese Journal of Geophysics

基　　金：国家重点基础研究项目(973)(2008CB425704)资助

摘　　要：统计分析低纬度环球带(E带)和环太平洋带(P带)在1900～2008年问M_W≥7.5地震的时空分布,进一步证实两者本身和两者之间都存在15～18年的幕式交替活动.将这两大地震带分别划分为5个地震区,发现这些分区地震幕式活动互不相同,但E带各区奇数幕与偶数幕年均地震数之比OER均大于1.58,而P带各区的OER均小于0.93,显示出前者以奇数幕活跃为特征,后者以偶数幕活跃为特征.对这些地震区的组合分析进一步证明,从幕式活动的共性看,中太平洋地区宜纳入E带.本文推论:低纬度环球带是另一条全球尺度地震带;大地震幕式活动的成因应归因于板块运动有几十年时间尺度的非平稳幕式运动;未来5～8年,E带的大地震还会比P带多.We have analyzed the temporal-spatial distributions of Mw≥7.5 earthquakes for 1900-2008 in the low-latitude circum-earth zone （E zone） and circum-Pacific zone （P zone）. The result shows that there are alternating episodes of events in each zone and between the two zones. We divide these two zones into five suhregions, respectively, and find that these subregions have distinct episodes of great quakes. In the E zone, the ratio of earthquake number of the odd episode to that of the even episode （OER） for each subregion is greater than 1.58, while that in the P zone is all less than 0.93. It means that the E zone is featured by active odd episodes and the P zone characterized by active even episodes. Combined analysis of these subregions indicates that the middle section of the circum-Pacific seismic zone can be placed into the E zone in view of the episode feature. This study infers that the low-latitude circum-earth zone is another seismic belt of global scale. The episodes of great earthquakes are likely attributed to unstable episodes of plate motions on a scale of several tens years. It is estimated that the E zone will suffer more great earthquakes than the P zone in future 5-8 years.

关 键 词：大地震 幕式活动 矩震级 板块运动 

分 类 号：P315[天文地球—地震学]