Page 291 - Acquisition and Processing of Marine Seismic Data

282 5. PREPROCESSING

FIG. 5.42 AGC gain corrections for applications of the scalar to different samples on a marine shot gather. (A) Filtered shot
with no gain, and its AGC corrected versions using 500 ms operator length for applications of the scalar to (B) trailing,
(C) leading, and (D) central samples of the AGC window.

FIG. 5.43 AGC corrections for different AGC operator lengths (Δt) on a marine shot gather. (A) Filtered shot with no gain,
and its AGC applied versions for (B) Δt ¼ 100 ms, (C) Δt ¼ 250 ms, (D) Δt ¼ 500 ms, (E) Δt ¼ 1000 ms, and (F) Δt ¼ 2000 ms
window lengths. There is a low-amplitude band just before the seabed reflection with a length of Δt/2 after AGC applied to the
central sample of the AGC window. The length of this quiet zone, however, is Δt if the AGC is applied to the leading sample.