Layer stripping FWI for surface waves

Abstract

In this study, an innovative layer stripping approach for FWI specifically adapted to the physics of surface waves is investigated, to mitigate the cycle skipping problem. A combined high-to-low frequency filtering with gradually increasing offset ranges, are applied to observed and calculated data to update gradually deeper layers of the shear velocity model. Successful results for a synthetic data example are presented.

3D wave-equation dispersion inversion of surface waves

“…where α is the step length and the superscript (k) denotes the k th iteration. In practice, a preconditioned conjugate gradient method is used, where source illumination is used as the preconditioning factor (Luo and Schuster, 1991).…”

“…However, further studies are needed to assess its robustness in convergence. To enhance robustness, a layer stripping strategy for FWI of surface waves was presented by Masoni et al (2016) who first invert the high-frequency and near-offset data for the shallow S-velocity model, and gradually incorporates lower-frequency data with longer offsets to estimate the deeper parts of the model. All these methods, however, are still under development and require more tests to fully understand their relative benefits and limitations.…”

Multiscale and layer-stripping wave-equation dispersion inversion of Rayleigh waves

“…The model is modified from Pérez Solano et al (2014) (Fig. 6d) and used by Masoni et al (2016) (Fig. 4).…”

2-D multiparameter viscoelastic shallow-seismic full-waveform inversion: reconstruction tests and first field-data application

“…One practical way to mitigate this problem is to use an initial model built by inverting surface-wave dispersion curves. Besides, an alternative objective function, such as amplitude-spectrum-based misfit (Pérez Solano et al 2014; 2D viscoelastic shallow-seismic FWI 3 Masoni et al 2016), envelope-based misfit (Wu et al 2014;Yuan et al 2015), and multi-objective misfit (Pan et al 2020), can be used to reduce the nonlinearity of surface-wave FWI.…”