Marine Seismic, 3

311 - CONSTITUANTS OF THE STREAMER : The streamer is a CABLE adapted to marine exploration ; it looks like a long plastic tube of about 5 cm diameter, its length may be up to several kilometers (streamers of 1200, 1600, 2400, 3600 and 4800 meters). The streamer is not made in one piece but consists of several elements : ACTIVE SECTIONS contain the HYDROPHONES and the DEAD SECTIONS which do not. The streamer contains the following elements : a steel stress member of about 5 mm diameter, the electrical conducters like those in a LAND cable, the 24, 36,48 TRACES (or more) which make up the active sections of which each one contains a number of hydrophones ( 30 to 50 ), finally the dead section, the water-tight junctions between the different elements, a liquid (kerosene or light oil) which fills the tube to give the streamer a density close to that of the water in which it will work.