Intrinsic non-uniqueness of the acoustic full waveform inverse problem

Chao Lyu (1) , Yann Capdeville (2) , David Al-Attar , Liang Zhao

1 IGG - Institute of Geology and Geophysics [Beijing]
2 LPG - Laboratoire de Planétologie et Géodynamique [UMR 6112]

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.

Mots clés: Inverse theory; Waveform inversion; Theoretical seismology; Computational seismology; Numerical modelling; Seismic anisotropy

Domaines: Géophysique [physics.geo-ph]

Chao Lyu, Yann Capdeville, David Al-Attar, Liang Zhao. Intrinsic non-uniqueness of the acoustic full waveform inverse problem. Geophysical Journal International, 2021, 226 (2), pp.795-802. ⟨10.1093/gji/ggab134⟩. ⟨hal-03306573⟩