** Next:** Conclusions
** Up:** Fomel & Prucha: Angle-gather
** Previous:** Velocity sensitivity

As pointed out by Prucha et al. (1999), the angle gathers
can be conveniently formed in the frequency domain. This conclusion
follows from the simple formula Fomel (1996a)

| |
(15) |

where *z* refers to the depth coordinate of the migrated image. In the
frequency-wavenumber domain, formula (15) takes the
trivial form
| |
(16) |

It indicates that angle gathers can be conveniently formed with the help
of frequency-domain migration algorithms Stolt (1978).
This interesting opportunity requires further research.

** Next:** Conclusions
** Up:** Fomel & Prucha: Angle-gather
** Previous:** Velocity sensitivity
Stanford Exploration Project

4/20/1999