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Acoustic versus Elastic 3-D FWI: a Case Study at the East Pacific Rise 9ºN
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 82nd EAGE Annual Conference & Exhibition - Workshop Programme, Oct 2021, Volume 2021, p.1 - 5
Abstract
Full Waveform Inversion (FWI) has become a standard tool for imaging subsurface. Although the acoustic formulation of the wave equation in FWI has been commonly used, excluding the elastic effect could have a significant impact on the inversion results. To quantitatively evaluate the contribution of the elastic approach, we compare acoustic and elastic 3-D FWI applied to a 3-D seismic data set from the East Pacific Rise (EPR) 9°50’ N, collected in deep-marine setting. After conducting a number of tests, we suggest a simultaneous, multi-parameter inversion using frequencies below 7 Hz for both acoustic and elastic approach. The resulting residual from the elastic case is 10–15% lower than that for the acoustic case, suggesting that the elastic approach explains the observed data better. Furthermore, the final compressional velocity model of the subsurface using the two approaches differ significantly, not only in velocity magnitude but also suggest different geological interpretation. We argue that the results obtained from the elastic modelling are geologically more plausible and more reliable image of the subsurface at the EPR.