Ellipticity filter for ground-roll removal

Surface waves are often dominant features of seismic records. As they remain near the surface, they contain no useful information and have to be attenuated. Surface waves include Rayleigh waves and guided waves propagating in the low-velocity layer, and known as pseudo Rayleigh waves. These waves are elliptical, whereas body waves are linearly polarized. This property has already been used by many authors for surface wave removal from multicomponent records. Wavelet decomposition provides a new way of separating surface and body waves, using an ellipticity criterion.