Publication Date:
2017-04-19
Description:
〈span class="paragraphSection"〉〈div class="boxTitle"〉Abstract〈/div〉We present a skeletonized inversion method that inverts surface-wave data for the 〈span style="font-style:italic;"〉Qs〈/span〉 quality factor. Similar to the inversion of dispersion curves for the 〈span style="font-style:italic;"〉S〈/span〉-wave velocity model, the complicated surface-wave arrivals are skeletonized as simpler data, namely the amplitude spectra of the windowed Rayleigh-wave arrivals. The optimal 〈span style="font-style:italic;"〉Qs〈/span〉 model is the one that minimizes the difference in the peak frequencies of the predicted and observed Rayleigh wave arrivals using a gradient-based wave-equation optimization method. Solutions to the viscoelastic wave-equation are used to compute the predicted Rayleigh-wave arrivals and the misfit gradient at every iteration. This procedure, denoted as wave-equation 〈span style="font-style:italic;"〉Qs〈/span〉 inversion (WQ〈sub〉〈span style="font-style:italic;"〉s〈/span〉〈/sub〉), does not require the assumption of a layered model and tends to have fast and robust convergence compared to full waveform inversion (FWI). Numerical examples with synthetic and field data demonstrate that the WQ〈sub〉〈span style="font-style:italic;"〉s〈/span〉〈/sub〉 method can accurately invert for a smoothed approximation to the subsurface 〈span style="font-style:italic;"〉Qs〈/span〉 distribution as long as the 〈span style="font-style:italic;"〉Vs〈/span〉 model is known with sufficient accuracy.〈/span〉
Print ISSN:
0956-540X
Electronic ISSN:
1365-246X
Topics:
Geosciences
Published by
Oxford University Press
on behalf of
The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
