Fifty-one three-component strong motion records have been digitized in a unified file on magnetic tape for rapid processing of observed accelerograms. Computer programs have been developed to calculate theoretical velocity waveforms by differentiating displacement waveforms computed according to Haskell's dislocation model and to calculate experimental waveforms by integration of the digitized acceleration records. Linear and cubic least squares corrections of the accelerogram and the integrated velocity waveform respectively have been found to result in reasonably reliable experimental velocity waveforms for interpretation with a moving dislocation model. A theoretical velocity waveform based on a linear ramp dislocation source time function appears to be superior to one based on an exponential ramp function when compared with the experimental waveform to interpret observed records. Dislocation processes associated with Parkfield and San Fernando earthquakes have been determined using the moving dislocation model.