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Homogenized Full Waveform Inversion : Application to Earth Model for Long Period Seismic Waves

Description: 

In order to understand the structure and dynamics of the Earth, seismic tomographic models are a precious tool. However the building of such models may be biased by such an interpretative goal. Switching paradigms, we can relax the interpretation aim to focus on building data-predictive models only, designed to perform source properties inversion for instance.

To proceed to the construction of such an Earth model, we applied a modified version of the classical Full Waveform Inversion (FWI), considering a full anisotropic setting of mechanical properties (21 elastic parameters and density), and a Gauss-Newton algorithm. Numerical simulations are performed using a spectral-element solver (SEM3D) in order to solve for both forward and adjoint wavefields, that give access to sensitivity kernels. Then, considering that the best model obtained by FWI is at best an effective model of the true one (as proposed by Capdeville & Métivier, 2018), a filtering step (whose operator comes from homogenization theory applied to nonperiodic media) provides a spatial regularization for the inverted model. With this in mind, a test-case is performed on a starting simplified Earth model with largely buried mantle heterogeneities. The resulting inverted, homogenized model, is very close to the homogenized starting model, as expected. The inverted model can therefore be considered as a good data-predictive model.

Session: 3D Wavefield Simulations: From Seismic Imaging to Ground Motion Modelling - III

Type: Oral

Date: 5/2/2024

Presentation Time: 02:45 PM (local time)

Presenting Author: Martin

Student Presenter: No

Invited Presentation: 

Authors