The quest for anisotropic moveout

There is renewed interest in velocity anisotropy, and publications of researchers outside SEP describe various schemes for estimating anisotropic moveout from seismic data. However, those schemes often face problems in that they commit too early to a particular class of elastic models which may require auxiliary information not available from surface seismic data. In essence, they are model-driven, not data-driven. This distinction has long been understood at SEP, where there is a ten-year record of developing practical schemes for characterizing non-hyperbolic moveout, whatever its cause. In this paper we distil the anisotropic wisdom of our past and outline the key features of a practical estimation procedure. Two data examples illustrate a method for estimating and removing anelliptic moveout in a CMP gather.