HR: 1340h
AN: S13A-0176    [Abstracts]
TI: Computing Uniformly Asymptotic Seismograms Using Complex Ray Tracing
AU: * Amodei, D
S13A-0176 AF: Department of Physics, Stanford University 382 Via Pueblo Mall, Stanford, CA 94305 United States
AU: Keers, H
EM: hkeers@cambridge.oilfield.slb.com
AF: Schlumberger Cambridge Research, Madingley Road, Cambridge, CB3 0EL United Kingdom
AU: Vasco, D
S13A-0176 AF: Lawrence Berkeley Laboratory, Earth Sciences Division 1 Cyclotron Road, Berkeley, CA 94720 United States
AU: Johnson, L
S13A-0176 AF: Lawrence Berkeley Laboratory, Earth Sciences Division 1 Cyclotron Road, Berkeley, CA 94720 United States
AB: Methods based on ray tracing are the tool of choice for modeling wave propagation through heterogeneous media at high frequencies. Reliable computation of amplitudes near caustics are still a problem though. We present a new method to compute these amplitudes accurately using complex rays and polynomial phase functions. This method allows the determination of global uniformly asymptotic solutions to the wave equation in the presence of arbitrarily many caustics. The model representation is done using the discrete cosine transform, rather than cubic splines. This way the velocity model can be analytically continued without higher order discontinuities at the interfaces of the interpolation cells. The complex two-point ray tracing is done efficiently, thus avoiding a global search of complex space. With this method amplitudes are not only correctly computed near caustics but also in the shadow zones. Seismograms are computed for both geometrical and uniformly asymptotic solutions, using a velocity model from the Yucca Mountain test site that generates caustics.
DE: 7203 Body waves
DE: 7260 Theory
DE: 7290 Computational seismology
SC: Seismology [S]
MN: Fall Meeting 2005