The seismic source was a Sodera-SSI Gi-Gun in Harmonic configuration 45+45 cubic inches except for 4 lines run at 60+60 c.i. Shot spacing was at a constant distance of 50 metres through the control of IGM's integrated navigation and gun control system [31]. The depth of the source ranged from 5 to 6 metres and pressure was set at 130-150 bars. The signature was constantly checked and tuned in order to obtain the optimum peak-to-bubble ratio. Due to the high speed of the survey, we used a GIN (V.Efimov) designed single-channel streamer, that provided an excellent signal/noise ratio. The depth of the streamer ranged from 5 to 7 metres. Data were reproduced, after amplification and filtering, in real time on two EPC 4800 recorders running at different timescales. The unfiltered data were routed to a digital acquisition system that produced SEG-D 3480 tapes at a sampling rate of 1 millisecond using a Geometrics Strataview Seismometer and Lookout Geophysical workstation.