1887

Abstract

Summary

We present a 2D elastic full waveform inversion (FWI) of Rayleigh waves (RW) with a genetic algorithm (GA) as the optimization tool and with a finite difference code as the forward modeling engine. To limit the computing time required by GA, we implement the RW FWI, making use of a two-grid parametrization of the subsurface model, one fine grid and one coarse grid, and of frequency marching during the evolution of the GA optimization. Forward modeling is performed on the fine grid to avoid numerical dispersion, while the GA inverts for the unknown velocities and densities at the nodes of the coarse grid. The coarser the grid the less the unknowns to be inverted for, at the expense of the final model resolution. Frequency marching also speeds up convergence because it has the ability of rejecting unrealistic models at the initial generations of the GA. Due to the very band-limited nature of RW, we suggest to start frequency marching from near the peak frequency of RW. Synthetic examples reproducing velocity inversions, lateral velocity variations and varying elevations show the feasibility of the proposed RW FWI, without any a-priori information and with shear-wave and compressional-wave velocities and densities as unknowns.

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/content/papers/10.3997/2214-4609.201701412
2017-06-12
2024-04-25
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References

  1. Aleardi, M. and MazzottiA.
    [2017] 1D elastic full-waveform inversion and uncertainty estimation by means of a hybrid genetic algorithm - Gibbs sampler approach. Geophysical Prospecting, 65, 64–85, doi: 10.1111/1365‑2478.12397.
    https://doi.org/10.1111/1365-2478.12397 [Google Scholar]
  2. Bunks, C., Saleck, F.M., Zaleski, S. and Chavent, G.
    [1995] Multiscale seismic waveform inversion. Geophysics, 60(5), 1457–1473, doi: 10.1190/1.1443880.
    https://doi.org/10.1190/1.1443880 [Google Scholar]
  3. Forbriger, T., Groos, L. and Schäfer, M.
    [2014] Line-source simulation for shallow-seismic data. Part 1: theoretical background. Geophys. J. Int., 198(3), 1387–1404,.doi: https://doi.org/10.1093/gji/ggu199.
    [Google Scholar]
  4. Komatitsch, D. and Martin, R.
    [2007] An unsplit convolutional perfectly matched layer improved at grazing incidence for the seismic wave equation. Geophysics, 72(5), SM155–SM167, doi: 10.1190/1.2757586.
    https://doi.org/10.1190/1.2757586. [Google Scholar]
  5. NagaiK., O’Neill, A., Sanada, Y. and Ashida, Y.
    [2005] Genetic Algorithm Inversion of Rayleigh Wave Dispersion from CMPCC Gathers Over a Shallow Fault Model. JEEG, 10(3), 275–286, doi: 10.2113/JEEG10.3.275.
    https://doi.org/10.2113/JEEG10.3.275 [Google Scholar]
  6. Sajeva, A., Aleardi, M., Stucchi, E., Bienati, N. and Mazzotti, A.
    [2016] Estimation of acoustic macro models using a genetic full-waveform inversion: Applications to the Marmousi model. Geophysics, 81(4), R173–R184, doi: 10.1190/geo2015–0198.1.
    https://doi.org/10.1190/geo2015–0198.1. [Google Scholar]
  7. Schäfer, M., Groos, L., Forbriger, T. and Bohlen, T.
    [2013] 2D full waveform inversion of recorded shallow seismic Rayleigh waves on a significantly 2D structure. Near Surface Geoscience 2013 - 19th European Meeting of Environmental and Engineering Geophysics, Bochum, Germany, Expanded Abstracts, doi: 10.3997/2214‑4609.20131338.
    https://doi.org/10.3997/2214-4609.20131338. [Google Scholar]
  8. Thorbecke, J.W. and Draganov, D.
    [2011] Finite-difference modeling experiments for seismic interferometry. Geophysics, 76(6), H1–H18, doi: 10.1190/geo2010‑0039.1.
    https://doi.org/10.1190/geo2010-0039.1. [Google Scholar]
  9. Xing, Z. and Mazzotti, A.
    [2016] Rayleigh waves modelling complexities in the perspective of full waveform inversion of surface waves - synthetic examples. Near Surface Geoscience 2016 - 22nd European Meeting of Environmental and Engineering Geophysics, Barcelona, Spain, Expanded Abstracts, doi: 10.3997/2214‑4609.201601909.
    https://doi.org/10.3997/2214-4609.201601909. [Google Scholar]
  10. Yilmaz, Ö.
    [2015] Engineering seismology with applications to geotechnical engineering. SEG Books, doi: http://dx.doi.org/10.1190/1.9781560803300.
    [Google Scholar]
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