Seismic Waveform Tomography With Simplified Restarting Scheme

Abstract

For shot-encoded seismic waveform tomography, the restarted L-BFGS algorithm is an effective technique to suppress the crosstalk effect among encoded seismic shots. It restarts the L-BFGS calculation at each iteration segment, consisted of a group of iterations, and re-codes the individual shots randomly not only at the beginning but also at the inside of the iteration segment. Here we simplified this scheme using an invariant shot-encoding within each iteration segment and recoding individual shots only at the beginning of the segment. This simplification did compromise the image quality at the early stage of inversion, as the crosstalk effect appeared on the inversion result of low-frequency data. However, it eventually achieved both the computation efficiency and the good quality for a multi-scale inversion procedure, which inverts seismic data from low-frequency components to high-frequency components in sequence.

Research note: Application of refraction full‐waveform inversion of ocean bottom node data using a squared‐slowness model parameterization

“…In this sense, the squared slowness model parameterization is a key choice to reduce the number of FWI iterations due to its faster convergence. As a perspective, we intend to investigate the combined impact between the model parameterization and optimization algorithms, such as limited‐memory Broyden‐Fletcher‐Goldfarb‐Shanno ( l ‐BFGS) approaches (Duarte et al., 2020; Rao & Wang, 2017; Rao et al., 2019), on estimating velocity models.…”

Preconditioned Conjugate Gradient Algorithm‐Based 2D Waveform Inversion for Shallow‐Surface Site Characterization

“…However, this new approximate-HM only explained the source geometric spreading. Another approach is to construct the approximate-HM by combining information from a gradient, model, and cost function, including L-BFGS [27,28], the corrected pseudo-Newton algorithm [10], and the pseudo-Newton algorithm [29].…”