Figure 2.10: In marine seismic exploration, cables called streamers are towed or ‘streamed’ behind a moving vessel. Inside the streamer are hydrophones that detect the pressure fluctuations in the water caused by reflected sound waves returning from the subsurface. The signals are converted into electric signals, which are digitised and transmitted along the streamer to a recording system on board the vessel. Instruments nicknamed ‘birds’ are used in streamer steering to control the depth and any lateral cable movement of streamers. It is important for the success of a seismic survey to know precisely the location of sources and receivers.
