Introduction

Angle-Domain Common-Image Gathers (ADCIGs) are often used for velocity analysis or Amplitude Versus Angle studies. Wavefield-continuation methods can easily generate angle gathers before Prucha et al. (1999) or after imaging Sava and Fomel (2000). The method proposed by Sava and Fomel (2000) assumes that the source and receiver rays propagate in a vertical plane, or that the source-receiver orientation is parallel to the dip of the reflector. This assumption is valid in 2-D and in some specific 3-D cases. In more general cases, however, this assumption and the method need to be revised. We propose an extension of the method such as it can be applied after the simpler case of common-azimuth migration, or after a more general full prestack migration. We present an application of the implementation of both extensions.