1.0 Technical Discussion 1.1 Background The Surface-Consistent Amplitude Compensation (SCAC) sequence attempts to compensate for shot, detector, or offset amplitude variations within a given seismic data set. After SCAC processing, the amplitudes for a given shot, detector, or offset should be the same as for any other shot, detector, or offset, respectively. Note that SCAC processing does not alter the trace signal-to-noise ratio. Suppose shot A is primarily noise and shot B is primarily signal. After SCAC processing, the noise in shot A will have the same amplitude as the signal in shot B. The SCAC processing sequence consists of three SFMs: Surface-Consistent Amplitude Compensation Pick (SCAC_PICK) SFM:Compute rms amplitude or mean absolute amplitude for the given time window. Surface-Consistent Amplitude Compensation Decomposition (SCAC_DECOMPOSITION) SFM:Decompose the amplitudes from SCAC_PICK into surface-consistent source terms, detector terms and offset terms. Surface-Consistent Amplitude Compensation Application (SCAC_APPLY) SFM: Compute and apply scaling factors to each trace in the given time window. The scaling factor is the ratio of the geometric mean of all the SCAC source, detector, and offset terms to the individual trace’s source, detector, and offset term.In addition, a FOURTH sfm can be inserted in the flow to better preserve the subsurface component of the amplitude correction. Please refer to the documentation for the SCAC_LONGWAVE_REMOVE sfm for further information.