The invention comprises a method for processing seismic data to generate data related to the location of thin beds in the earth's subsurface. Seismic data windows are defined extending over selected portions of a group of spatially related seismic data traces. Frequency spectra of successively selected windows of the seismic data are generated by applying a transform having poles on the unit z-circle, where z is the z-transform, to the data windows; and the frequency spectra are utilized to generate data related to the location of thin beds in the earth's subsurface.