Although the simplicity of migration by Kirchhoff methods is attractive, many authors have demonstrated that Kirchhoff methods are not optimal for areas with complex subsurfaces (, ). () demonstrated that Kirchhoff methods in the angle domain may still have artifacts in strongly refracting media, even when using the correct velocity and all arrivals. The problem at the heart of the Kirchhoff methods is its high frequency assumption. The Kirchhoff equation explicitly assumes that the behavior of the seismic waves can be adequately described through the use of rays and that the image can be obtained by summing over a given number of these rays rather than using all of the energy present in the data. This assumption breaks down for very complex subsurfaces. Fortunately, other methods based on the wave equation do not have this high frequency assumption and do use all of the energy present in the data. In this thesis, the imaging method I will use is downward-continuation migration.

10/31/2005