Figure 2. Example of (a) original prestack time migrated vertical seismic amplitude section, and (b) the same section after performing residual velocity analysis. Note the improved stratal definition within the Chicontepec interval, as demarcated by the red bracket and also below the shallow volcanic body. The frequency spectra corresponding to each volume indicates significant frequency enhancement; (c) and (d) represent equivalent coherent energy slices along the yellow horizon in (a) and (b).