Spectral-element based 3D elastic full-waveform inversion of surface waves in the presence of complex topography using an envelope-based misfit function

Significant topographic variations will strongly influence the amplitudes and phases of propagating surface waves. Such effects should be taken into account, otherwise the S-velocity model inverted from the Rayleigh dispersion curves will contain significant inaccuracies. We now show that the recently developed wave-equation dispersion inversion (WD) method naturally takes into account the effects of topography to give accurate S-velocity tomograms. Application of topographic WD to demonstrates that WD can accurately invert dispersion curves from seismic data recorded over variable topography. We also apply this method to field data recorded on the crest of mountainous terrain and find with higher resolution than the standard WD tomogram.

Section: Introductionmentioning

confidence: 99%

Wave equation dispersion inversion of surface waves recorded on irregular topography

Lin

Allam

et al. 2019

“…Besides modifying the inversion strategy to alleviate the cycle-skipping issue, other objective functions rather than the conventional least-squares objective function can be considered. Borisov et al (2016) apply an envelope objective function (Bozdag et al 2011) to the SEAM II model (Oristaglio 2016) and obtain better inversion results than with the least-squares objection function. Furthermore, Yuan et al (2015) decompose the seismic data using wavelet transform before applying the envelope function.…”

Section: Introductionmentioning

confidence: 99%

Land seismic multiparameter full waveform inversion in elastic VTI media by simultaneously interpreting body waves and surface waves with an optimal transport based objective function

Brossier

Métivier

et al. 2019

SUMMARY Land seismic multiparameter full waveform inversion in anisotropic media is challenging because of high medium contrasts and surface waves. With a data-residual least-squares objective function, the surface wave energy usually masks the body waves and the gradient of the objective function exhibits high values in the very shallow depths preventing from recovering the deeper part of the earth model parameters. The optimal transport objective function, coupled with a Gaussian time-windowing strategy, allows to overcome this issue by more focusing on phase shifts and by balancing the contributions of the different events in the adjoint-source and the gradients. We first illustrate the advantages of the optimal transport function with respect to the least-squares one, with two realistic examples. We then discuss a vertical transverse isotropic (VTI) example starting from a quasi 1-D isotropic initial model. Despite some cycle-skipping issues in the initial model, the inversion based on the windowed optimal transport approach converges. Both the near-surface complexities and the variations at depth are recovered.

“…Han et al (2016) inversion. For a large-scale 3D problem, the feasibility of using the envelope inversion on synthetic elastic data (Borisov et al, 2016) and synthetic anisotropic data (Wang and Tsvankin, 2016) has been verified. However, the feasibility of applying the envelope inversion on real field data has not yet been examined.…”

Section: Introductionmentioning

confidence: 99%

Full waveform inversion using envelope-based global correlation norm

Alkhalifah

2018

CitationOh J-W, Alkhalifah T (2018) Full waveform inversion using envelope-based global correlation norm. Geophysical Journal International. to recover long-wavelength structure in an early stage. In addition, the envelope-based global correlation norm maintains the advantage of the global correlation norm, which reduces the sensitivity of the misfit to amplitude errors so that the performance of inversion on real data can be enhanced when the exact source wavelet is not available and more complex physics are ignored.Through the synthetic example for 2D SEG/EAGE overthrust model with inaccurate source wavelet, we compare the performance of 4 different approaches, which are the least squares waveform inversion, least squares envelope inversion, global correlation norm and envelopebased global correlation norm. Finally, we apply the envelope-based global correlation norm on the 3D OBC data from the North Sea. The envelope-based global correlation norm captures the strong reflections from the high-velocity caprock and generates artificial lowfrequency reflection energy that helps us recover long wavelength structure of the model domain in the early stages. From this long-wavelength model, the conventional global correlation norm is sequentially applied to invert for higher-resolution features of the model.