Development and testing of a general modelling technique
Discrete representations of the relevant equations of motion in seismics are derived from a pseudo-spectral approach. The 3D acoustic/ elastic case and generalisations for viscoacoustic/elastic and anisotropic media are successively considered. Two new time- integration methods are developed. These methods permit more efficient and accurate calculations of a propagating wavefield than finite difference approaches. A new hybrid modelling scheme for the 2D acoustic case is formulated, based on a combination of the finite difference method and local boundary Green's functions. Dependent on the applied modelling algorithm two approaches for an elimination of boundary reflections are elaborated and tested. When applying discrete seismic modelling methods, difficulties can arise with regard mainly to the free surface simulation, the source point implementation and the approximation of irregular interfaces. Reliable solutions and recipes are outlined for these special problems. Prototypes of vectorisable computer codes are developed. These comprise a 3D structure generator and postprocessing routines for a flexible graphic display of the results. In addition, information on the computing resources required by the modelling programs is provided. Numerical examples for 3D/2D acoustic/elastic, viscoacoustic/elastic, and anisotropic models are presented.
Bibliographic Reference: EUR 12826 EN (1990) 117 pp., FS, ECU 10
ISBN: ISBN 92-826-1560-X
Record Number: 199011211 / Last updated on: 1994-12-01
Original language: en
Available languages: en