一种基于密集线性台阵的虚拟地震测深新方法及其应用  

New VDSS method based on dense linear array and its applications

作　　者：魏晓拙 姜明明[1,3] 陈凌 王旭 WEI Xiao-zhuo;JIANG Ming-ming;CHEN Ling;WANG Xu(Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;University of Chines Academy of Science,t, Bering 100049, China;CAS Center for Excellence in Tibetan Plateau Earth Sciences, Bejing 100101, China;State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China)

机构地区：[1]中国科学院地球与行星物理重点实验室中国科学院地质与地球物理研究所,北京100029 [2]中国科学院大学,北京100049 [3]中国科学院青藏高原地球科学卓越创新中心,北京100101 [4]岩石圈演化国家重点实验室中国科学院地质与地球物理研究所,北京100029

出　　处：《地球物理学进展》2018年第3期986-992,共7页Progress in Geophysics

基　　金：国家自然科学基金面上项目(41274002);国家科技重大专项(2011ZX05008-001);Sina Probe-02-03项目联合资助

摘　　要：本文提出了一种基于密集线性台阵的虚拟地震测深新方法,该方法在引入密集线性台阵数据的基础上,对之前广泛应用的单台虚拟地震测深方法进行了改进.针对复杂构造地区,新方法不再依赖传统的平面波入射假设,而是通过直接提取测线上的Ss直达波与Ss Pmp反射波震相走时,来更准确地约束反射点处Moho面深度.我们将新方法应用于跨龙门山构造带布设的密集流动地震台阵数据,对扬子克拉通与青藏高原构造边界带下方的地壳厚度进行了研究.结果表明扬子克拉通西部地壳相对较薄,地壳在龙门山构造带内部沿北西向迅速增厚.该区域地壳厚度变化特征可能与自新生代以来印度—欧亚板块碰撞所导致的青藏高原隆升过程有关.与单台虚拟地震测深方法相比,新方法对于复杂构造区域地壳厚度,如跨龙门山构造带,有着更可靠的约束.This research proposes a new Virtual Deep Seismic Sounding（ VDSS） method. The new method improves the traditional single station VDSS technique by using dense linear array data. For places with complex underground structures,the new method does not depend on the planar wave incidence assumption,but extracts the Ss and Ss Pmp arrival time on the linear array directly,to determine the moho depth more accurately. We apply this method to a linear dense array which is deployed across the Longmenshan tectonic boundary zone,to investigate the local crustal thickness. We find that the crust is relatively thinner under the western part of the Yangtze Craton,and its thickness increases in the Longmenshan boundary zone,from the east to the west. The crustal thickness variations in this area may be related to the uplift process of the Tibetan Plateau,which is produced by the collision between the Indian and Asian plate. Compared with the single station VDSS method,the new method can constrain the crustal thickness of complex tectonic zones, such as the Longmenshan boundary zone,better.

关 键 词：虚拟地震测深 地壳厚度 龙门山 

分 类 号：P315[天文地球—地震学]