Figure shows the data after the far offsets have been removed. A multiple train caused by the fast middle layer has died down over the inner offsets at the time of the anomaly. Therefor, removing the far offsets, we were able to create a nearly multiple free data volume for imaging purposes. The middle half of the total offset range was kept. Figure is the image produced by shot-profile migration using all the available data. Figure shows the image for the step anomaly and the scallop anomaly. Identical images were created by stacking all of the shots and migrating with a planar horizontal source function, and source-receiver migration (not shown).
Figure 2 Shot-profile migration using all available data. Interference from intrabed multiples from middle layer decreases image quality.
To understand the importance of multiple shots, two single shot data volumes were migrated with shot-profile migration. Figures is the image from a shot located at the left edge of the model space. The bottom reflector is very poorly imaged, and their is no indication of the anomaly. If the shot were located directly over the anomaly, as in Figure , the anomaly is noticeable though the quality of the image is poor.