Abstract : Classical algorithms used for traveltime tomography are not necessarily well suited for handling very large seismic data sets or for taking advantage of current supercomputers. The classical approach of first-arrival traveltime tomography was revisited with the proposal of a simple gradient-based approach that avoids ray tracing and estimation of the Fréchet derivative matrix. The key point becomes the derivation of the gradient of the misfit function obtained by the adjoint- state technique. The adjoint-state method is very attractive from a numerical point of view because the associated cost is equivalent to the solution of the forward-modeling problem, whatever the size of the input data and the number of unknown velocity parameters. An application on a 2D synthetic data set demonstrated the ability of the algorithm to image near-surface velocities with strong vertical and lateral variations and revealed the potential of the method.
https://hal-mines-paristech.archives-ouvertes.fr/hal-00519453
Contributeur : Mark Noble
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Soumis le : lundi 20 septembre 2010 - 13:03:35
Dernière modification le : lundi 12 novembre 2018 - 11:03:26
Cédric Taillandier, Mark Noble, Hervé Chauris, Henri Calandra. First arrival travel time tomography based on the adjoint state methods. Geophysics, Society of Exploration Geophysicists, 2009, 74 (6), pp.WCB57-WCB66. ⟨hal-00519453⟩
