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First Arrival Traveltime Tomography Using the Fast Marching Method and the Adjoint State Technique
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 77th EAGE Conference and Exhibition 2015, Jun 2015, Volume 2015, p.1 - 5
Abstract
Classical algorithms used for first arrival traveltime tomography are not necessarily well-suited for handling very large seismic data sets, densely parameterized velocity models and for taking advantage of current supercomputers architecture. Several authors have recently revisited the classical approach of first arrival traveltime tomography by proposing to use a gradient-type approach based on the adjoint-state of the eikonal equation. With the adjoint-state technique the gradient of the objective function can be obtained without the explicit estimation of the Fréchet derivative matrix, which is computationally prohibitive for large-scale problems. We propose a new robust, efficient numerical implementation of the adjoint state technique combined with the fast marching method. This scheme allows us to compute the gradient of the misfit function with respect to velocity, it also enable us to build up an approximation of the Hessian. This approach is a very effective solution for processing huge and dense surveys with no compromise in terms of amount of data and model description.