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WITHDRAWN Seismic Imaging, Full-Waveform Inversion and Inverse-Scattering

Description: 

WITHDRAWN Seismic imaging or seismic migration is widely used in both exploration and earthquake seismology, and plays an important role in both fields. I In this study, we try to build an intrinsic link between seismic imaging, full-waveform inversion, and inverse-scattering.

Seismic imaging can be defined as a time-space focusing process. Backpropagator, or the reverse-time propagator (e.g. reverse-time finite difference algorithm), is the focusing operator which refocuses the recorded scattered field on the surface back to their original locations and the imaging principle is a time-focusing (choice of correct focusing time). Seismic waveform inversion is closely related to seismic imaging. For example, the current FWI (full-waveform inversion) is basically an iterative process of imaging + medium parameter transform which converts the image field into a medium parameter field. Though closely related, there are important differences between imaging and inversion. First, in general, unlike the imaging process where the focusing operator is known (the velocity structure is known), the objective of inversion is to construct or reconstruct the focusing operator so that the imaging process can be performed and improved. In principle, the velocity (or other parameter) structure is unknown and obtaining such structure is the goal of inversion. The construction or reconstruction of the focusing operator is a highly nonlinear process and is critical to seismic inversion. Nevertheless, in current FWI the focusing operator is assumed approximately known, namely the initial model in the inversion is assumed to be fairly close to the true velocity structure. Inverse-scattering, based on the classic GLM (Gel'fand-Levitan-Marchenko) integral equation, is an exact solution for the inverse-scattering problem and tries to extend the 1-D exact theory to the 3-D case. We will also investigate the relationship between inverse-scattering and a recently proposed Direct Waveform Inversion (DWI) scheme.

Session: Seismology for the Energy Transition [Poster]

Type: Poster

Date: 4/18/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Ru-Shan Wu

Student Presenter: No

Invited Presentation: 

Authors