A system for modeling the output signal emanating from a seismic vibrator based on a superposed collection of damped harmonic oscillators, whose critical parameters are determined from signals from accelerometers on the baseplate and reaction mass portions of the vibrator together with the input force (pilot sweep). This modeled output signal is a more accurate representation of the seismic signal that propagates into the earth and may be used in the cross-correlation process to significantly enhance the accuracy of the recorded seismic data. Additionally, by modeling the output signal on a shot by shot basis, any changes in the ground's surface can be monitored and/or documented, and, if required, the sweep parameters can be varied shot by shot for optimum performance.