Figure shows the semblance for a dataset containing only one source. Figure is after adding another source of 10 times larger in amplitude at depth of 300 feet. This is the unwanted or interfering source. The first source is totally hidden by this stronger source. Figure was obtained after removing the stronger source using the single-channel algorithm.

The next dataset also contains two sources, but the ratio of amplitudes is 50. Figure shows the result of applying the single-channel algorithm to this dataset. The weaker source can not be seen after the subtraction. The result of applying the multi-channel algorithm is shown at Figure . Obviously, here subtraction did a very good job of suppressing the unwanted source.

Figure 1

Semblance for depth 1000 meters, one source.

Figure 2

Semblance for depth 1000 meters, two sources, ratio 1:10.

Figure 3

Semblance after applying single-channel subtraction, two sources, ratio 1:10.

Figure 4

Semblance after applying single-channel subtraction, two sources, ratio 1:50.

Figure 5

Semblance after applying multi-channel subtraction, two sources, ratio 1:50.

12/18/1997