Using a velocity log from a given area impulsional synthetic seismograms with and without multiples are computed by digital techniques. The effect of the automatic gain control and of the recording process are then taken into account by using the digital filters corresponding to the actual analog systems. The resulting synthetic seismograms are compared, the multiples are identified and their probable origins are found. Further comparison with the actual field record obtained in the area shows an excellent agreement with the synthetic seismogram with multiples.