摘要
远震层析成像是研究一个地区上地幔三维速度结构的有力手段.但由于远震射线在地壳内的交叉较差,因此无法准确约束地壳内的三维速度结构.为了消除地壳内横向不均匀性对深部速度成像产生的影响,必须进行地壳校正.本文详细描述了地壳校正的基本原理和步骤,主要包括三维地壳模型的选取、地壳内走时差的计算以及校正后的相对走时差的计算.以勘察加地区为例,通过计算各台站的平均相对走时差和远震层析成像结果分析了地壳校正的实际效果,同时验证了该方法的实用性.
Teleseismic tomography is a powerful technique for determining the 3-D upper mantle structure under a region, but it cannot determine the 3-D crustal structure well because the teleseismic rays do not crisscross well in the crust. Hence it is crucial to make crustal corrections to remove the effect of lateral crustal heterogeneity from the observed travel-time data. In this work we describe a technique for conducting the crustal correction in teleseismic tomography, which includes the choice of 3-D crustal model, the calculations of the travel-time residual in the crust and the relative residual after the crustal correction. We choose the Kamchatka region as an experiment to analyze the validity of the crustal correction via the mean relative residuals at each station and the results of teleseismic tomography, and also to verify the applicability of the technique for making crustal correction.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第6期1508-1514,共7页
Chinese Journal of Geophysics
基金
863计划重大项目(2006AA06A202
2006AA06A203)
日本文部科学省研究基金(Kiban A-17204037)资助
关键词
地壳校正
远震层析成像
走时差
三维地壳模型
Crustal correction, Teleseismic tornography, Travel-time residual, 3-D crustal model
