汶川地震序列中较大深度余震的一种可能的直接观测证据  

Events with Depths Larger than 30km in the 2008 Wenchuan Aftershock Sequence: A Possible Direct Evidence

作　　者：刘春[1] 吴忠良[2] 蒋长胜[2] 

机构地区：[1]陕西省地震局,西安市边家村水文巷4号710068 [2]中国地震局地球物理研究所,北京100081

出　　处：《中国地震》2009年第2期113-122,共10页Earthquake Research in China

基　　金：国家科技部项目(2004CB418406)资助

摘　　要：汶川地震序列中为数很少的深度大于30km的余震是否存在,对解释汶川地震的成因机制具有重要意义。本文分析了汶川地震序列中26个"恰好"发生在观测台站下方的小地震——"台下地震",利用这种地震与台站之间的特殊组合来确定这些地震的震源深度,以期为地震精确定位提供"GT事件"。在这26个地震中,有两例的震源深度约36km,尽管仍与所采用的地壳结构模型有关,却也提供了深度大于30km的余震存在的直接证据。Whether there exist events with depths larger than 30km in the aftershock sequence is a critical problem in the seismogenetie model of the 2008 Wenehuan earthquake. In this work, we considered 26 aftershocks ＂just underneath＂ seismic stations. Making use of such special station-event configuration to determine the depths of these micro-earthquakes provided accurate relocation of aftershocks with a reference set of ＂ground truth （GT） events＂. In these aftershocks, two events have the depth about 36km. Although still being structure-model-dependent, this observation provides a direct evidence for the existence of the events deeper than 30km.

关 键 词：地震定位 汶川地震 余震序列 GT事件 

分 类 号：P315[天文地球—地震学]