Comparison of ray methods with the exact solution in the 1-D anisotropic "twisted crystal" model

Summary

The exact analytical solution for the plane S wave, propagating along the axis of spirality in the simple 1-D anisotropic "twisted crystal" model, is known. In this contribution, the exact solution and eight ray-theory approximate solutions of different provenance are numerically compared. The eight approximate solutions are: (a1) coupling ray theory solution calculated by evaluating the analytical solution of the coupling ray theory equations, (a2) coupling ray theory solution calculated by 3-D ray tracing package CRT, (a3) coupling ray theory solution calculated by 3-D ray tracing package ANRAY, (b1) zero-order quasi-isotropic approximation to the coupling ray theory calculated by evaluating the analytical solution of the quasi-isotropic ray theory equations, (b2) zero-order quasi-isotropic approximation calculated by 3-D ray tracing package ANRAY, (c1) anisotropic ray theory solution calculated by evaluating the analytical solution of the anisotropic ray theory equations, (d1) isotropic ray theory solution calculated by evaluating the analytical solution of the isotropic ray theory equations, (d2) isotropic ray theory solution calculated by 3-D ray tracing package CRT.

Keywords

Coupling ray theory, quasi-isotropic approximation, anisotropic ray theory, isotropic ray theory, validity conditions of ray methods.

Whole paper

The image of the paper in GIF 150dpi (392 kB) is designed for an instant screen preview.

The paper is available in PostScript (828 kB, colour figures) and GZIPped PostScript (260 kB, colour figures).

Expanded abstract

Bulant, P., Klimes, L. & Psencik, I.: Comparison of ray methods with the exact solution in the 1-D anisotropic "twisted crystal" model. Expanded Abstracts of 70th Annual Meeting (Calgary), pp. 2289-2292, Soc. Explor. Geophysicists, Tulsa, 2000.

SW3D