Page 306 - Acquisition and Processing of Marine Seismic Data

5.8 MUTING 297

ensure that the muting is applied to the data areas of continental margins, which requires
properly. This is especially important in the case definition of a rapidly changing top mute zone,
of top muting, because it is not feasible to pick depending on the water depth along the line.
top mute polygons on every single shot along Since the polygon interpolation is performed
the line, and generally top mute polygons are automatically, the processor must be sure that
picked on every 50 or 100 shots, depending on any areas of the erratic seabed are not acciden-
the number of shots in the data (Fig. 5.61A). tally muted out. Fig. 5.61B shows an example
Between these shots, mute polygons are auto- stack section with a mound structure on the
matically interpolated. However, water depth sea floor. After stacking followed by a top mute,
along the line can be erratic, especially in the a significant amount of data is also muted out

FIG. 5.61 (A) Top mute polygons (red curves) manually picked on every 100 shots. (B) An example stack section including a
mound structure without top mute, and (C) the same stack followed by an incorrect top mute application. A significant
amount of data is improperly muted out around the mound (data shown by dashed lines) because of the sparse picking of
the top mute polygons on the shot gathers.