【摘要】 本文介绍了断层活动的一种重要现象——特征地震现象.特征地震是指某些断层长期活动过程中,重复发生的多次大地震往往表现出相似的破裂长度、位错分布、和震级大小,而有些活动断层在多次地震中表现出局部的相似.对断层地震活动的统计分析中,有两种模型,一种就是为大家熟知的G-R经验公式,还有一种就是特征地震模型.到底哪一种模型能够代表断层的活动,用哪一种模型进行地震危险性分析较为合理?南加州断层历史地震的统计资料和一些数值模拟分析的结果表明对于一条成熟的单个断层,用特征地震模型进行解释是更为合理的,而对包含多条断层的较为广阔的地域,断层活动应该仍用G-R公式进行分析.文章的后面对特征地震的机制进行了分析,特别地,我们认为断层的位错分布主要是由断层破裂面处地震前后的应力降决定的.所以对成熟断层而言,断层上发生的多次重复地震由于地震孕育的条件相似,导致断层活动中表现出特征地震这种现象.更多还原

【Abstract】 An important phenomenon -"characteristic earthquake" on active faults is introduced.In the long history of some active faults,the repetition earthquakes often show analogous magnitude,analogous dislocation distribution and analogous ruptures,which are named characteristic earthquakes.Some active faults show local characteristic earthquakes.In the statistics of historical earthquakes of active fault there are two models.Which model is more reasonable:G-R relationship model or characteristic earthquake model? The statistical data of historical earthquakes on the South California faults and some numerical simulation show that the characteristic earthquake model is suitable for a single mature fault,the G-R relationship is suitable for a wide area which consists of many faults.In the end of the paper,we analyse the mechanism of the characteristic earthquake.Earthquake dislocation is determined by the stress drop on the fault rupture plane mostly.So for mature active faults,because of same conditions for the repeat earthquakes pregnancies,active faults often show these characteristic earthquakes.更多还原