A DCAMM seminar will be presented by
Professor Loukas Kallivokas
The University of Texas at Austin, USA
Abstract:
We discuss the development of a full-waveform-inversion-based methodology for the imaging of near-surface formations using sparse data. Specifically, we address the imaging of arbitrarily heterogeneous sites in three dimensions, using elastic waves as probing agents and the response of the site recorded at sparsely distributed surface sensors.
We cast the associated inverse medium problem directly in the time domain and use PDE-constrained optimization ideas to obtain the profile of the probed site in terms of the spatially-distributed Lamé parameters (or the P- and S-wave velocities). We report on Tikhonov and TV regularization, a source frequency-content continuation scheme, regularization factor continuation, and search-direction biasing that are all used in order to assist the optimizer’s convergence.
We report numerical results for both synthetic and field-collected data. For the field studies, we also report on a validation approach that served as a strong indicator of the correctness of the reconstructed site profile.
Danish pastry, coffee and tea will be served 15 minutes before the seminar starts.
All interested persons are invited