Three-dimensional full waveform inversion of short-period teleseismic wavefields based upon the SEM-DSM hybrid method

Abstract : We present a method for high-resolution imaging of lithospheric structures based on full waveform inversion of teleseismic waveforms. We model the propagation of seismic waves using our recently developed direct solution method/spectral-element method hybrid technique, which allows us to simulate the propagation of short-period teleseismic waves through a regional 3-D model. We implement an iterative quasi-Newton method based upon the L-BFGS algorithm, where the gradient of the misfit function is computed using the adjoint-state method. Compared to gradient or conjugate-gradient methods, the L-BFGS algorithm has a much faster convergence rate. We illustrate the potential of this method on a synthetic test case that consists of a crustal model with a crustal discontinuity at 25 km depth and a sharp Moho jump. This model contains short- and long-wavelength heterogeneities along the lateral and vertical directions. The iterative inversion starts from a smooth 1-D model derived from the IASP91 reference Earth model. We invert both radial and vertical component waveforms, starting from long-period signals filtered at 10 s and gradually decreasing the cut-off period down to 1.25 s. This multiscale algorithm quickly converges towards a model that is very close to the true model, in contrast to inversions involving short-period waveforms only, which always get trapped into a local minimum of the cost function.
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Geophysical Journal International, Oxford University Press (OUP), 2015, 202 (2), pp.811-827. 〈10.1093/gji/ggv189〉
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Contributeur : Dimitri Komatitsch <>
Soumis le : dimanche 31 janvier 2016 - 04:09:59
Dernière modification le : lundi 4 mars 2019 - 14:04:08

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Vadim Monteiller, Sébastien Chevrot, Dimitri Komatitsch, Yi Wang. Three-dimensional full waveform inversion of short-period teleseismic wavefields based upon the SEM-DSM hybrid method. Geophysical Journal International, Oxford University Press (OUP), 2015, 202 (2), pp.811-827. 〈10.1093/gji/ggv189〉. 〈hal-01265155〉

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