Vertical Transverse Isotropy FWI
Vertical Transverse Isotropy FWI: A finely layered isotropic medium with horizontal interfaces is characterized by propagation velocities that depend on the angle of incidence. Waves that only prop-agate horizontally have the same propagation velocity regardless of azimuthal angle, but if they have a vertical component, then their speed depends on the polar angle of propagation. This type of medium is known as a vertical transverse isotropic (VTI) medium; another type of VTI medium is one in which the anisotropy is intrinsic to the minerals. The VTI propagation velocities are a function of the rock strength that varies with respect to strain direction.