CONCLUSION

Using a given velocity model, the Snell-beam transform maps data from the offset--traveltime domain into the horizontal-slowness--vertical-traveltime domain. This transform can be used as an alternative to the usual $\tau-p$ transform to perform the plane wave decomposition of the data, with the difference that no further moveout correction is required. Furthermore, as opposed to local slant-stacks, geometrical corrections are performed in an appropriate way (within a 2.5 D assumption), without losing the advantages of a local stack transform.

The application of the transform to synthetic data shows a good agreement between shapes of the amplitude curves of the several different elastic interfaces, and their theoretical curves.

The results are also in accordance with the application of the $\tau-p$ transform, followed by a normal-moveout correction to the vertical traveltime. However, multiples and noises in general are weaker on the Snell-beam transform, due to the local character of the beam-stack transform.

To retrieve the reflectivity matrix (R(t₀,p)) several operations are necessary. The Snell-driven beam-stack transforms the recorded data into the desired t₀-p domain, with the additional compensation for divergence, and radiation pattern.