Waveform inversion in the shifted Laplace domain

Kwon, Jay-Hyoun; Jun, Hyoung Oh; Song, Hyeonjun; Jang, Ugeun; Shin, Changsoo

doi:10.1093/gji/ggx170

Cited by 4 publications

(1 citation statement)

References 28 publications

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“…Therefore, it is also an effective method in taking measures to mitigate nonlinearity in the FWI. Constructing a more convex objective function is a widely used method: The Laplace domain inversion and Laplace‐Fourier domain use the zero‐frequency and low‐frequency components of the damped wavefield to obtain the long‐wavelength components of the subsurface (Cha & Shin, ; Ha et al, , ; Ha & Shin, ; Kwon et al, ; Shin & Cha, , ; Shin et al, ). Similar to the layer stripping and time window methods (Y. H. Wang & Rao, ; Yoon et al, ), FWI uses the time‐damping wavefield to invert the velocity model in a shallow‐to‐deep manner to reduce the risk of the inversion falling into a local minimum (Chen et al, , ; Choi & Alkhalifah, ).…”

Section: Introductionmentioning

confidence: 99%

Multiscale Direct Envelope Inversion: Algorithm and Methodology for Application to the Salt Structure Inversion

Chen

2019

Earth and Space Science

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For the full‐waveform inversion, obtaining a globally optimal solution is difficult when the seismic data do not contain sufficient low‐frequency information and the inversion object is a salt structure with a large‐scale salt dome. The large salt dome presents difficulty for the inversion of the salt structure; however, it also confers a convenience that can be utilized: A large salt dome makes the events in the seismic record sparse and isolated. We use the envelope to obtain the arrival time of the events in the seismic data and apply multiscale strategies to extract the low‐frequency information of the seismic data that relates to the long‐wavelength components of the subsurface. In calculating the gradient, the envelope Fréchet derivative is used to take advantage of the multiscale envelope for the characteristics of the salt structure. Therefore, the multiscale direct envelope inversion using the window‐averaged envelope and the direct envelope Fréchet derivative is proposed. To further improve the computational efficiency and inversion quality of the multiscale direct envelope inversion, several auxiliary strategies are proposed: A joint misfit function is designed to make the inversion method more adaptable, and an offset weighting factor is introduced to implement the multioffset inversion method to improve the inversion quality of subsalt. We analyze the antinoise performance of the multiscale direct envelope inversion. The SEG/EAGE salt model is used to test the application effect of the multiscale direct envelope inversion. The antinoise ability and insensitivity to low‐frequency data of the method are verified in the numerical experiments.

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Section: Introductionmentioning

confidence: 99%

Multiscale Direct Envelope Inversion: Algorithm and Methodology for Application to the Salt Structure Inversion

Chen

2019

Earth and Space Science

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Robust elastic full-waveform inversion using an alternating direction method of multipliers with reconstructed wavefields

Aghazade,

Gholami,

Aghamiry

et al. 2024

GEOPHYSICS

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Elastic Full Waveform Inversion (EFWI) is a process used to estimate subsurface properties by fitting seismic data while satisfying wave propagation physics. The problem is formulated as a least squares data fitting minimization problem with two sets of constraints: PDE constraints governing elastic wave propagation and physical model constraints implementing prior information. The Alternating Direction Method of Multipliers (ADMM) is used to solve the problem, resulting in iterative algorithm with well-conditioned subproblems. Although wavefield reconstruction is the most challenging part of the iteration, sparse linear algebra techniques can be used for moderate-sized problems and frequency domain formulations. The Hessian matrix is blocky with diagonal blocks, making model updates fast. Gradient ascent is used to update Lagrange multipliers by summing PDE violations. Various numerical examples are used to investigate algorithmic components, including model parameterizations, physical model constraints, the role of the Hessian matrix in suppressing interparameter cross-talk, computational efficiency with the source sketching method, and the effect of noise and near surface effects.

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