On singularity points in elastic orthorhombic media

Abstract

The analysis of singularity points in anisotropic models of low symmetry is very important for seismic modelling and seismic data processing. Ray tracing: the group velocity vector dramatically changes the orientation in vicinity of singularity point. Seismic amplitudes: the relative geometrical spreading of seismic wave tends to zero in singularity point. Seismic wave polarization: the polarization vectors dramatically change in vicinity of singularity point. Multiarrival: one of the waves has triplication associated with singularity point, another wave has a lacuna.The singularity points are considered for elastic anisotropic model with orthorhombic symmetry. The conditions for the presence of singularity points are derived depending on location of these points, in symmetry plane and in-between the symmetry planes. The explicit equations for images of the singularity points in group velocity domain are derived. The conditions for different types of degeneracy of these images are defined. We also perform the analysis of interaction of the group velocity images of different singularity points.