Largescale finitedifference and finiteelement frequencydomain seismic wave modelling with multilevel domaindecomposition preconditioner
Abstract
The emergence of longoffset sparse stationaryrecording surveys carried out with ocean bottom nodes (OBN) makes frequencydomain full waveform inversion (FWI) attractive to manage compact volume of data and perform attenuation imaging. One challenge of frequencydomain FWI is the forward problem, which requires the solution of large and sparse linear systems with multiple righthand sides. While direct methods are suitable for dense acquisitions and problems involving less than 100 million unknowns, iterative solver are more suitable for large computational domains covered by sparse OBN surveys. Here, we solve these linear systems with a Krylov subspace method preconditioned with the twolevel Optimized Restricted Additive Schwarz (ORAS) domain decomposition preconditioner, the prefix optimized referring to the use of absorbing conditions at the subdomain interfaces. We implement this method with finite differences on uniform grid and finite elements on unstructured tetrahedral meshes. A simulation in a model where the velocity linearly increases with depth allows us to validate the accuracy of the two schemes against an analytical solution while highlighting how their relative cost varies with the band of propagated wavelengths. A simulation in the overthrust model involving up to 2 billions of parameters allows us to tune the method and highlights its scalability.
 Publication:

arXiv eprints
 Pub Date:
 March 2021
 arXiv:
 arXiv:2103.14921
 Bibcode:
 2021arXiv210314921D
 Keywords:

 Physics  Computational Physics
 EPrint:
 arXiv admin note: substantial text overlap with arXiv:2004.07930, arXiv:2004.06309