Page 212 - Acquisition and Processing of Marine Seismic Data

3.10 OTHER NOISE TYPES 203

FIG. 3.33 (A) A raw common offset section with strong harmonic noise interference (E) and its amplitude spectrum (upper
panel), and (B) after application of a notch filter to remove the harmonic noise at 50 Hz and its multipliers followed by a 12–
180 Hz band-pass filter.

higher than correlated and un-correlated noise causes deadly issues during the migration: the
embedded in the data, they cannot be sup- spikes create semicircular artifacts (so called
pressed by stacking and spikes also exist on “smiles”) after migration, which may
the stack sections as localized noise bursts completely corrupt the data (Fig. 3.35B); this
(Fig. 3.35A). The f-k filters may increase their makes it important to remove them before stack-
amplitudes and make them much clearer on ing. Although there are some specific algorithms
the stack data. If not removed, this type of noise to automatically search and remove spikelike