Inverse Scattering of Guided Waves

Thursday, April 25, 2002 - 9:30am - 10:30am
Keller 3-180
Gerard Herman (Technische Universiteit te Delft)
The objective of seismic exploration is to determine rock properties and geological structure of the subsurface of the earth from seismic recordings. As such, it is an inverse scattering problem with many challenges. One of those is the fact that most of the seismic energy is trapped near the earth's surface and never reaches the deeper layers of interest for oil and gas exploration.

We are developing methods for removing the effect of these trapped (or guided) waves. By using asymptotic methods, the propagation can be described accurately and efficiently. An important step in the method is the estimation of global properties of the near-surface and their local deviations. These local deviations can be of the size of the seismic wavelengths and, consequently, give rise to severe scattering. By determining the parameters relevant for this scattering process, we are able to reduce the effect of the guided waves.