ESR2.b: Theodor BECKERAcoustic data-driven time reversal

Theodor BECKER: I have always been interested in the physical processes that shape our planet. Additionally, I have a great passion for the mountains and being outside. For those reasons I completed a Bachelor of Science in Geosciences at the University of Potsdam (Germany) and University of Montana (USA). For the Master of Sciences I specialized in Applied Geophysics and I spent one semester each at TU Delft (Netherlands), ETH Zurich (Switzerland), RWTH Aachen (Germany) and Schlumberger Gould Research (UK). I recently started a PhD at ETH Zurich. My research is related to numerical modelling and physical experimentation of acoustic wave propagation, scattering, data-driven time-reversal and wave field focusing.

Main host institution:

ETH Zürich (Zürich, Switzerland)

SupervisorS:

Dirk-Jan van Manen (dirkjan.vanmanen @ erdw.ethz.ch)& Johan Robertsson, (johan.robertsson @ erdw.ethz)Kees Wapenaar (C.P.A.Wapenaar @ tudelft.nl), Lasse Amundsen (lam @ statoil.com)

Secondment institutions:

• Seismic Technologies, (The Hague, Netherlands)
• Faculty of Civil Engineering, Delft University of Technology (Delft, Netherlands)

Objectives:

The ETH WaveLab is in principle a perfect time-reversal cavity, all its boundaries being densely covered by transducers that can record and emit acoustic waves15.

The ESR will take advantage of this unique facility to research and test experimentally both existing methods that rely on time reversal16 17.

Time-reversal is closely related to focusing, which in turn is relevant to medical acoustics: the proposed work will build on earlier applications in that field, where, e.g., high-energy waves are focused to "burn" cancer cells18; important challenges like source directivity and attenuation, that can limit the sharpness of focusing, will be considered and addressed from an interdisciplinary perspective.

Expected resultS:

• First experimental demonstration of perfect time-reversal (in the diffraction limit).
• Novel data-driven time-reversal algorithms, without the “source-inside” requirement, and experimental demonstration.
• Improved theoretical understanding of the data-driven focusing problem for arbitrarily complex media and the link with one-sided data-driven focusing (aka. Marchenko redatuming).
• Experimental demonstration of Marchenko redatuming.

international conferences:

EAGE Annual Meeting in Vienna 30/05 - 2/06/2016: "Anisotropic Velocity Model Calibration in Surface Monitoring Using Microseismic Events - A Case Study”

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further information:

Theodor Becker's LinkedIn page