GNGTS 2014 - Atti del 33° Convegno Nazionale

The SEG-D raw data were processed on a dedicated workstation. The quality control was performed on board, both on the single shots and the whole profiles by screen display and plotting of the near trace sections. The quality control and the preliminary processing were performed on board by means of the GEDCO Vista Seisimage package. A conventional processing sequence was applied that included trace editing, amplitude recovery, band pass filtering, interactive velocity analyses, normal move out corrections and stack. The seismic data acquisition was coupled with the acoustic detection of the water column using the Kongsberg EM710 and EM302 multibeam systems that are both hull-mounted on board the R/V Urania. Water column data were processed with the Fledermaus Midwater Tab. 1 - General seismic acquisition parameters. ACQUISTION PARAMETERS SOURCE RECEIVERS RECORDING Model Mini GI-GUN Sercel Model Geoeel Model Geometrics Volume Single 60 cu.in . Length 300 m Sampling rate 0.5 ms Gun Mode 30G+30I Harmonic Ch. No. 96 Record length 2.5 sec Shot Interval 9.375 m Ch. Dist. 3.125 m LC filters 3 Hz (LC); Depth 1.5 m Depth 1.5 m HC filters Antialias Pressure 140 atm. Min off. 25 m SYNCHRONIZATION Max off. 325 m Controller RTS Sure Shot Max fold 16 Aim Point 50 ms delay Fig. 2 – Stacked gas plumes detected in the water column by the EM302 multibeam system along a transect over the R1MV mud volcano. Location in Fig. 1. 172 GNGTS 2014 S essione 1.2