In the Novemeber/Decemeber 1999 Geophysics, Abma, Sun, and Bernitsas provide corrections to the anti-aliasing calculations found in the 1994 SEG Extended Abstracts by Lumley, Claerbout, and Bevc, pages 1282-1285. The expression for the maximum frequency given in Lumley et. al. is incorrect for long offsets and low velocities. Shown below are plots of the result of a migration using the Lumley et. al. expressions, the result of using the corrections from Abma et. al., and a result without anti-aliasing. Notice that the Lumley et.al result is overfiltered on the shallow far offsets.
----------- Lumley et.al. anti-aliasing ----------- Abma et. al. anti-aliasing ----------
------------- No anti-aliasing ----------------- No migration, nmo only ----------
The input dataset is in common-offset order, with a trace spacing within the common offset of 50 meters. The offsets vary from 0 to 2950 meters with a offset increment of 50 meters.
This is version 2 of this page. The first version had an error in processing the velocities for the migration.