Using Wavefield Adapted Meshes in a Global Scale Full-Waveform Inversion

Session: Full-Waveform Inversion: Recent Advances and Applications [Poster]
Type: Poster
Date: 4/29/2020
Time: 08:00 AM
Room: Ballroom
Description: 

With the steadily increasing availability and density of seismic data, full-waveform inversion (FWI) can reveal the Earth's subsurface with unprecedented resolution. In order to achieve such resolutions, higher frequencies are required and the computational cost of FWI scales with frequency to the power of 5. Even with the ever-increasing power of high-performance computing resources, these massive compute requirements inhibit substantial progress and require algorithmic and technological innovations for global and continental scale inversions.

In this contribution we present an approach to FWI where we achieve significant computational savings through wavefield adapted meshing. In laterally smooth media, we can construct meshes which are adapted to the expected complexity of the wavefield by making anisotropic adaptive mesh refinements. By optimally designing a unique mesh for each source, we can reduce the computational cost of wavefield simulations by an order of magnitude. Through the discrete adjoint approach we can achieve similar speed-ups in gradient computations without a sacrifice in accuracy. Wavefield adapted meshes help to remedy the frequency scaling issue as one dimension is quasi-independent of frequency thus opening up the potential of the feasibility of global scale simulations at higher frequencies than before.

Recent work presented the applicability and limitations of the wavefield adapted meshes in FWI. Ongoing work is to upscale the work presented in that publication and combine it with a dynamic mini-batch approach [1], which further remedies the frequency scaling issue making FWI less dependent on the number of sources used in the inversion. We demonstrate a prototype FWI for this approach towards a global scale inversion with real data.

[1] van Herwaarden, DP., Boehm, C., Afanasiev, M., Krischer, L., van Driel, M., Thrastarson, S., Trampert, J., Fichtner, A. 2019. Accelerated full-waveform inversion using dynamic mini-batches. Submitted to Geophysical Journal International

Presenting Author: Solvi Thrastarson

Authors