Refraction traveltime tomography using damped monochromatic wavefield SCIE SCOPUS

Cited 14 time in WEB OF SCIENCE Cited 20 time in Scopus
Title
Refraction traveltime tomography using damped monochromatic wavefield
Author(s)
Pyun, S; Shin, C; Min, DJ; Ha, T
Publication Year
2005-03
Abstract
For complicated earth models, wave-equation-based refraction-traveltime tomography is more accurate than ray-based tomography but requires more computational effort. Most of the computational effort in traveltime tomography comes from computing traveltimes and their Frechet derivatives, which for ray-based methods can be computed directly. However, in most wave-equation traveltime-tomography algorithms, the steepest descent direction of the objective function is computed by the backprojection algorithm, without computing a Frechet derivative directly. We propose a new wave-based refraction-traveltime-tomography procedure that computes Frechet derivatives directly and efficiently. Our method involves solving a damped-wave equation using a frequency-domain, finite-element modeling algorithm at a single frequency and invoking the reciprocity theorem. A damping factor, which is commonly used to suppress wraparound effects in frequency-do main modeling, plays the role of suppressing multievent wavefields. By limiting the wavefield to a single first arrival, we are able to extract the first-arrival traveltime from the phase term without applying a time window. Computing the partial derivative of the damped wave-equation solution using the reciprocity theorem enables us to compute the Frechet derivative of amplitude, as well as that of traveltime, with respect to subsurface parameters. Using the Marmousi-2 model, we demonstrate numerically that. refraction traveltime tomography with large-offset data can be used to provide the smooth initial velocity model necessary for prestack depth migration.
ISSN
0016-8033
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/5092
DOI
10.1190/1.1884829
Bibliographic Citation
GEOPHYSICS, v.70, no.2, pp.U1 - U7, 2005
Publisher
SOC EXPLORATION GEOPHYSICISTS
Subject
RAY TOMOGRAPHY; INVERSION; MIGRATION
Type
Article
Language
English
Document Type
Article
Publisher
SOC EXPLORATION GEOPHYSICISTS
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