Serge Sambolian, ITES

À la uneÉvénement passé
8 février 2024
13h, salle du conseil

 High-resolution seismic imaging: from tomography to full-waveform inversion. Can we exploit our data in a better way?

In active seismic imaging, the tomographic macro-model is seen as a smooth representation, containing only the long wavelength components, of the exact subsurface model. We often resort to migration methods to resolve the short wavelengths or full-waveform inversion (FWI) to recover short to intermediate wavelengths. Two main steps of the seismic imaging emerged historically, recovering low wavenumbers through tomography first and then reconstruct high wavenumbers through migration or FWI. In theory, macro-models are in most cases enough to explain well the kinematics governing wave propagation, especially for diving waves and most single-scattered arrivals. On the other hand, in some complex settings, these models are not accurate enough to serve as initial guess for FWI.
Aside from the ill-famed challenges of the seismic imaging workflow. We discuss in this seminar how data are often underexploited, especially in academia. A high-resolution reflection tomography method is then presented. Slope tomography exploit the density of the data to the fullest with subsurface parameters drastically more resolved than the ones derived through conventional methods. After a recap on the main obstacles of an FWI-based workflow, we look at how multi-component data could be much better exploited, offering superior robustness compared to vanilla FWI recipes.