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Twin Wavefront Construction Approach to Simulation of Shear Waves in Transversely Isotropic Layered Media
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 78th EAGE Conference and Exhibition 2016, May 2016, Volume 2016, p.1 - 5
Abstract
We present a novel approach to simulation of shear (S) waves in transversely isotropic layered media, based on the wavefront construction method. Each ray code specifying S-wave simulation will give rise to two runs of the wavefront construction process, one run for each elementary (twin) S wave. For one S-wave twin the polarization, in local anisotropy coordinates, is assumed mainly of type SV; for the other twin the polarization is mainly SH. The method allow for models that consists of heterogeneous elastic layers separated by generally shaped interfaces. Inside the layers the type of elasticity is either isotropic or transversely isotropic. The symmetry axis of transverse isotropy may have arbitrary orientation and is allowed to change direction smoothly inside the layers. We use standard ray theory for transversely isotropic media, not an average type of ray computation. This ensures accurate traveltimes in situations of strong anisotropy. The introduction of a ‘fat singularity’ guarantees continuous polarization directions in a region around an S-wave singularity. One may optionally apply coupling ray theory for continuation of amplitude along the rays.