Robust acoustic and elastic full waveform inversion by adaptive Tikhonov-TV regularization

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Autori principali: Aghazade, Kamal, Gholami, Ali
Natura: Preprint
Pubblicazione: 2025
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author Aghazade, Kamal
Gholami, Ali
author_facet Aghazade, Kamal
Gholami, Ali
contents Full Waveform Inversion (FWI) is a powerful wave-based imaging technique, but its inherent ill-posedness and non-convexity lead to local minima and poor convergence. Regularization methods stabilize FWI by incorporating prior information and enforcing structural constraints like smooth variations or piecewise-constant behavior. Among them, Tikhonov regularization promotes smoothness, while total variation (TV) regularization preserves sharp boundaries. However, in the context of FWI, we highlight two key shortcomings of these regularization methods. First, subsurface model parameters (P- and S-wave velocities, density) often exhibit complex geological formations with sharp discontinuities separating distinct layers, while parameters within each layer vary smoothly. Neither Tikhonov nor TV regularization alone can effectively constrain such piecewise-smooth structures. Second, and more critically, when the initial model is far from the true model, these regularization assumptions can lead to a local minimum. To address these issues, we propose adaptive Tikhonov-TV (TT) regularization, which decomposes the model into smooth and blocky components, enabling robust recovery of piecewise-smooth structures. Implemented within the ADMM framework, TT regularization incorporates an automated balancing strategy based on robust statistical analysis. Numerical experiments on acoustic and elastic FWI using benchmark geological models demonstrate that TT regularization significantly improves convergence and reconstruction accuracy compared to Tikhonov and TV regularization when applied separately. We show that for complex models and remote initial models, both Tikhonov and TV regularization tend to converge to local minima, whereas TT regularization effectively mitigates cycle skipping through its adaptive combination of the two regularization strategies.
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id arxiv_https___arxiv_org_abs_2505_04022
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Robust acoustic and elastic full waveform inversion by adaptive Tikhonov-TV regularization
Aghazade, Kamal
Gholami, Ali
Geophysics
Full Waveform Inversion (FWI) is a powerful wave-based imaging technique, but its inherent ill-posedness and non-convexity lead to local minima and poor convergence. Regularization methods stabilize FWI by incorporating prior information and enforcing structural constraints like smooth variations or piecewise-constant behavior. Among them, Tikhonov regularization promotes smoothness, while total variation (TV) regularization preserves sharp boundaries. However, in the context of FWI, we highlight two key shortcomings of these regularization methods. First, subsurface model parameters (P- and S-wave velocities, density) often exhibit complex geological formations with sharp discontinuities separating distinct layers, while parameters within each layer vary smoothly. Neither Tikhonov nor TV regularization alone can effectively constrain such piecewise-smooth structures. Second, and more critically, when the initial model is far from the true model, these regularization assumptions can lead to a local minimum. To address these issues, we propose adaptive Tikhonov-TV (TT) regularization, which decomposes the model into smooth and blocky components, enabling robust recovery of piecewise-smooth structures. Implemented within the ADMM framework, TT regularization incorporates an automated balancing strategy based on robust statistical analysis. Numerical experiments on acoustic and elastic FWI using benchmark geological models demonstrate that TT regularization significantly improves convergence and reconstruction accuracy compared to Tikhonov and TV regularization when applied separately. We show that for complex models and remote initial models, both Tikhonov and TV regularization tend to converge to local minima, whereas TT regularization effectively mitigates cycle skipping through its adaptive combination of the two regularization strategies.
title Robust acoustic and elastic full waveform inversion by adaptive Tikhonov-TV regularization
topic Geophysics
url https://arxiv.org/abs/2505.04022