Intrinsic non-uniqueness of the acoustic full waveform inverse problem. Issue 2 (6th April 2021)

• Record Type: Journal Article
• Authors: Lyu, Chao; Capdeville, Yann; Al-Attar, David; Zhao, Liang
• Is Part Of: Geophysical journal international. Volume 226:Issue 2(2021)
• Page Start: 795
• Page End: 802
• Publication Date: 2021-04-06
• Subjects: Inverse theory -- Numerical modelling -- Waveform inversion -- Computational seismology -- Seismic anisotropy -- Theoretical seismology; Geophysics -- Periodicals; 550
• DOI: 10.1093/gji/ggab134
• Languages: English
• ISSNs: 0956-540X

Abstract

SUMMARY: In the context of seismic imaging, full waveform inversion (FWI) is increasingly popular. Because of its lower numerical cost, the acoustic approximation is often used, especially at the exploration geophysics scale, both for tests and for real data. Moreover, some research domains such as helioseismology face true acoustic media for which FWI can be useful. In this work, an argument that combines particle relabelling and homogenization is used to show that the general acoustic inverse problem based on band-limited data is intrinsically non-unique. It follows that the results of such inversions should be interpreted with caution. To illustrate these ideas, we consider 2-D numerical FWI examples based on a Gauss–Newton iterative inversion scheme and demonstrate effects of this non-uniqueness in the local optimization context.