渭河断陷地壳三维S波速度结构和V_p/ V_s分布图像  

THREE-DIMENSIONAL SHEAR WAVE VELOCITY STRUCTURE AND DISTRIBUTION IMAGE OF Vp/Vs BENEATH THE WEIHE FAULT DEPRESSION

作　　者：丁韫玉[1] 狄秀玲[1] 袁志祥[1] 薛广盈 

机构地区：[1]陕西省地震局,西安710068 [2]海南省地震局,海口570003

出　　处：《地球物理学报》2000年第2期194-202,共9页Chinese Journal of Geophysics

基　　金：地震科学联合基金!95208

摘　　要：利用陕西及邻省区域地震台网的观测数据，采用重叠元迭代重建层析成像技术，结合两点快速射线追综，对渭河断陷盆地地壳的Ｓ波速度进行了层析反演成像．并利用前期Ｐ波速度的研究结果，计算了该地区地壳的 Ｖ_ｐ／ Ｖ_ｓ分布．研究结果表明：（１）Ｓ波速度分布两个地区存在强烈的横向不均匀性，其一是陕晋交界的合阳、永济地区，二是铜川、泾阳地区，它们都位于不同构造单元交汇地带，差异运动显著，是新老地层交错的地区．（２）历史强震震中主要分布在Ｓ波的高速区及边缘地带。（３）在淳化、耀县、泾阳之间存在Ｖ_ｐ／Ｖ_ｓ高值区，最高达２．１．Using the seismic data observed by the seismic networks in Shanxi province and neighbor regions, we studied seismic tomographic imaging of the crustal S wave velocity in the Weihe fault basin by overlapping-shear iterative reconstruction method with the two-points fast ray tracing technique. On the basis of the velocity ratio Vp/ Vs in the same region is calculated. The results show that (1) there are two strong lateral no homogenous regions of S wave velocity distribution, one of which is Heyang-Yongji region on the boundary between Shanxi and Shanxi provinces and the other is Tongchuan-Jingyang zone. Those two areas are located in a region where different tectonic units meet, and differential movement is significant and different rock strata are interceded, (2) the historical strong earthquakes occurred mainly in S wave high-velocity regions on their boundaries; (3) a region with high Vp / Vs value (highest of 2.1) is enclosed by the areas of Chunhua, Yaoxian and Jingyang.

关 键 词：层析成像 渭河断陷 S波速度 盆地地壳 分布图像 

分 类 号：P315.2[天文地球—地震学] P542.3[天文地球—固体地球物理学]