The computation of a finite-frequency travel time sensitive kernel for P-waves in the AK135 earth model  

地球AKl35模型中P震相的有限频走时灵敏度算核的计算(英文)

作　　者：张风雪[1] 吴庆举[1] 潘佳铁[1] 张广成[1] 冯强强[1] 

机构地区：[1]中国地震局地球物理研究所,北京100081

出　　处：《Applied Geophysics》2011年第2期158-163,178,共7页应用地球物理（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No. 90814013)

摘　　要：Finite-frequency travel time tomography is a newly developing method.The main procedure in this new method is to compute the traveltime sensitive kernel.The travel time of the same scatterer needs to be used for computing the traveltime sensitive kernel many times.It is a time-consuming task.It is easy and fast to get the travel time from analytic equations in a simple model such as a homogenous or linear velocity media.However,most of the earth models are layered.It is cumbersome to get the travel time from analytic equations.In order to enhance the computation efficiency,we used the table look-up method to compute the finite-frequency travel time sensitive kernel for P-waves in a layered structure model.We chose the AK135 earth model for the velocity model.The table look-up method saved about 50% of the computation time.We enhanced the computation speed by using the table lookup method in the same velocity model,which was very useful for enhancing the computation efficiency for the finite-frequency travel time tomography.有限频走时层析成像是近年发展起来的一种新方法,这种新方法的一个主要过程是走时灵敏度算核的计算。求解灵敏度算核要多次用到同一散射点的走时,多次地求解同一走时是相当耗时的任务,如果介质为均匀或速度线性变化等简单模型,散射点的走时可以用解析公式快速地求出,从而灵敏度算核的计算耗时相对较少。然而各种地球模型中,介质速度大多为分层模型,从解析公式中得到走时信息就比较繁锁。为了提高计算效率,本文采用查表算法研究地球分层速度模型中的P震相有限频走时灵敏度算核的计算,选用的速度模型是地球AKl35模型,用查表算法求解走时,节省了约50%的计算时间。在相同的速度模型下,与已有结果的对比,本文所用的查表算法,能在兼顾精度的前提下,以较小的存储要求换取较高的计算效率,这对提高有限频走时层析成像算法的速度具有一定的参考价值。

关 键 词：AK135 finite-frequency sensitive kernel P-WAVE 

分 类 号：P631.4[天文地球—地质矿产勘探]