f True amplitude aspects of pre-stack depth migration

In the past decade, pre-stack depth migration algorithims have been developed to image complex geologic structures in a proper way. however, in recent years it has been shown that, if seismic inversion is formulated as a sequence of processing steps, pre-stack depth migration can also be sean as one of the principal steps in seismic inversion. This means a.o. that the interest in the amplitude behaviour of seismic migration has been significantly increased. Bleistein (1987) uses the method of stationary phase to compute true amplitude reflection coefficients. In a recent paper Hubral et al (1991) discus the problem of true amplitude zero offset time migration, using raylracing arguments . In the past we have shown by wave theoretical argument show to apply true amplitude pre-stack depth migration to shot records (see e.g . Berkhout, 1984, chapter VII and Wapenaar and Berkhout, 1989, chapter XI). In this paper we will show, also by wave theoretical arguments, how to apply true-amplitude pre-stack depth migration to any subset of pre-stack data such as CMP gathers and common offset sections. Of course, the proposed process is suitable to handle irregular offsets as well.