印度板块与欧亚板块在兴都库什—帕米尔地区相互俯冲的动力作用分析  

Dynamic action of mutual subduction between the Indian and the Eurasia plates in Hindu Kush-Pamir region

作　　者：张浪平[1] 邵志刚[1] 李志海[2] 

机构地区：[1]中国地震局地震预测研究所地震预测重点实验室,北京100036 [2]新疆维吾尔自治区地震局,乌鲁木齐830011

出　　处：《地球物理学报》2014年第2期459-471,共13页Chinese Journal of Geophysics

基　　金：国家科技支撑计划项目(2012BAK19B0104)资助

摘　　要：兴都库什—帕米尔地区是印度板块与欧亚板块相互碰撞的强烈变形区域,也是中国大陆与周边板块动力传递的关键部位,明确该地区两大板块俯冲接触的几何形态和动力作用对研究区域动力环境具有实际意义.本文首先基于Hayes等在2009和2010年提出的Slab1.0的研究思路,利用地震参数准定量地给出两大板块在兴都库什—帕米尔地区碰撞接触的几何形态.结果表明,印度板块在兴都库什地区呈现自南往北的俯冲;欧亚板块在帕米尔地区呈现由北往南的俯冲;同时在兴都库什和帕米尔之间存在俯冲交汇区,在该区印度板块以北西方向、欧亚板块以南东方向相互俯冲.其次基于哈佛大学提供的震源机制解,对不同接触部位进行了应力张量反演,结果显示在兴都库什俯冲区域主要表现为逆冲性质,帕米尔弧西段主要表现为走滑性质,且均具有较好的一致性;而在俯冲交汇区域,走滑、逆冲性质并存,表现为震源机制一致性紊乱.结合两大板块接触的几何形态和区域应力场反演结果,认为印度板块在兴都库什地区主动往北俯冲,而欧亚板块在帕米尔地区被动往南东—南向俯冲,形成两大板块的相互俯冲.本文从几何形态和应力场反演分析两大板块在兴都库什—帕米尔地区碰撞的动力作用方式,可为该区域地球动力学相关研究提供基础资料.Hindu Kush-Pamir region is a strongly deformed region related to the collision between the Indian and the Eurasia plates,it is also the critical part of force transmission between China's Mainland and its surrounding plates,consequently,it is meaningful to define contact geometry and dynamic action between two plates in the region for regional dynamic environmentstudy.Initially,based on the research approach of Slab1.0proposed by Hayes et al.in 2009and2010,using seismic parameters of shallow and intermediate-depth earthquakes,we quasiquantitatively present a collision and contact geometry of the two plates in Hindu Kush-Pamir region.The result shows that the Indian plate subducts beneath Eurasia plate from south to north in Hindu Kush region,and the Eurasia plate performs subduction under Indian plate from north to south in Pamir region,simultaneously;a subduction intersection zone exists between Hindu Kush and Pamir,where the Indian and the Eurasia plate subduct towards each other in Northwest and Southeast direction respectively in this region.In addition,based on the focal mechanism solutions offered by Harvard University,the stress tensor inversion for different contact areas is carried out.The result shows that the stress tensor is mainly of thrust type in Hindu Kush subduction area and strike-slip in the western part of the Pamir arc,and demonstrates good consistency.However,strike-slip and thrust coexist in the subduction intersection zone,and the focal mechanism solutions show inconsistency.Combined the contact geometry of the two plates and the inversion results of regional stress field,this study considers that,the Indian plate subducts actively to the north in Hindu Kush region,and the Eurasia plate subducts to southeastsouth passively in Pamir region,accordingly,forming the mutual subduction of the two plates.We analyze the dynamic action mode of the collision between the two plates in Hindu Kush-Pamir based on the geometry and the inversion results of regional stress field,which could provide basic d

关 键 词：兴都库什—帕米尔地区 几何形态 中源地震 应力场反演 Slab1 0 

分 类 号：P542[天文地球—构造地质学]