This section presents three examples in which we applied the method described in the last section. The first two applications are on simple Gaussian velocity anomalies in a medium of constant velocity. We used these models to check the validity, accuracy, and stability of the HWT method. The third example concerns the very complex Marmousi 2-D model, which is one of the most difficult benchmarks for ray tracing methods. Throughout the test, we have compared our results with those obtained with Rekdal's PRT program Rekdal and Biondi (1994) for accuracy, speed, and stability.