CONCLUSIONS

According to the Huygens secondary point source principle, the surface recorded wavefields can be regarded as a series of point sources. My research has demonstrated the application of Gaussian beam wave propagation theory to downward continue the surface recorded wavefields. Poststack and prestack depth migration are accomplished by applying appropriate imaging conditions to the downward continued wavefields. This research has also demonstrated that the Gaussian beams evaluated along only seventeen rays from each surface seismogram location can image a fairly complex velocity and reflectivity model.