4 Channel SEGY Readme

21 March 2006

4 channel streamer data collected aboard the RV Revelle on the AMAT 03 RR cruise.
recorded as segd and converted to segy with the geometry applied.  Files are 
named by Julian Day and GMT time. Underway seismic was collected at a ship speed of 10 knots. If the 4-channel streamer was used for a site survey, the data was collected at a nominal ship velocity of 6 knots. Check the SEG-D header data for actual velocities during acquisition.

SOURCES:
Two (2) 150 cu. in. GI Airguns configured to 45 cu. in. Generator and 105 cu. in. Injector, each gun. Recorded at an 8 second shot window, with a 10 second shot-interval. Recorded at 0.5ms sample spacing. 

We archive 3 SEG-y files--
(1) a raw file compiled from the SEG-D shots (e.g., Transit_JD77_0834_shot6892.sgy)
(2) a stacked but otherwise unprocessed file(e.g., Stacked_JD77_0834_shot6892.sgy),
and
(3) a stacked, bandpass filter, and migrated file (e.g., mig_stacked_JD77_0834_shot6892.sgy)

GEOMETRY:
Receiver Spacing 50 m
Ship speed 10 kts
Shot interval 10 seconds
Shot Spacing 50 m
Maximum fold 2

STACKED and MIGRATED:
Bandpass filter
Zero phase butterworth15-30-250-500
Iterative Stolt Migration
Maximum frequency to Migrate is 250
RMS velocity 1500