We employed high resolution Multichannel Seismic (Fig. 10) using the GI-GUN (Fig.12) (in the 105+105 c.i. Harmonic configuration) pneumatic sources by SODERA/SSI, powered by a 2500 L/Min, electrically driven, Mod. I28 air compressor by BAUER. The pressure to the gun was set to 175 Bar (2500 psi), actually ranging from 165 to 185 Bars. The seismic data were collected by a MOD.29500 TELEDYNE 48 channel streamer (Fig.11) and digitized and recorded on DDS-1 and DDS-2 DAT tapes by a GEOMETRICS's STRATAVISOR seismograph in the SEG-D 8048 Revision.0 format, with Sampling rate of 1 msec and Record Lenghts varying from 8 to 12 secs .
The group interval was of 12.5m for a total active length of 600m. The 150m tow leader and two 50 m stretch sections made up the streamer to a total length of 850m. The seismic source was fired by IGM's gun-control equipment [10](Fig. 13), that introduced a fixed delay of 10 msec from the Time Break, where the Injector delay was of 47.5 msec. Shot distances were of 50 m, thus achieving coverages of 600%. The Time Break was provide by the Seismic Module in the NAVPRO Navigation System Software, with the 'DISTANCE FROM PREVIOUS SHOT' setting, in order to maximize the survey flexibility allowing the 'SHOT NOW' capability when on route. This was particularly important when dealing with high traffic or fishing activities that forced last minute deviations from the planned route. The depth of the source ranged between 5 and 6 m. The streamer was kept at 10-12 m depth with SYNTRON RCL-2 cable-levelers, using a Teledyne Mod. 28951 Depth Control System.
The data were processed onboard using the DISCO/FOCUS packages by PARADIGM, up to the time-migration of the sections, using a standard processing sequence.
