The effect of velocity variations on the beam width of a seismic wave

The effect of depth and lateral velocity variations on the width of a seismic beam propagating through the earth is investigated. The model used is unusual and provides an interesting alternative insight to the conventional models appearing in the peophysical literature. Some basic calculations show that, at frequencies and depths of interest in oil exploration, a significant lateral shift in the centre of the seismic beam occurs in addition to the expected broadening of the seismic beam.