When a shear wave propagates through an anisotropic medium, such as a geologic formation, it becomes polarized, or split, into a PS1 and PS2 component with an orientation related to the stress regimes and fracture systems present in the rock. These polarization orientations can change from formation to formation and compound on one another as a converted shear wave propagates upward to the receiver. They can also vary laterally and with offset requiring careful consideration.
These effects show up as an azimuthally dependent time delay on the radial component and corresponding amplitude extinctions and polarity flips on the transverse.
In these cases we can estimate this effect and either compensate for it or create interpretable products based in the PS1/PS2 domain. Each layer of polarization is carefully measured and removed one at a time, improving the radial stack response and gleaning useful information about the subsurface.