Hydrophone Streamer
The diagram above illustrates the basic construction of a high resolution hydrophone streamer (derived from Prada, K.E. The 200 element streamer, an array for seismic profiling, Woods Hole Oceanographic Institution: Woods Hole Oceanographic Institution Technical Report 67-64. 1967). |
The hydrophone streamer acts as a receiving device for some acoustic sources. It receives the reflected signal, an acoustic (sound) pressure wave, and converts it to an electrical signal. The streamer is constructed of a number of transducers that are electrically wired together to act as one receiving system. This string of elements is placed in a flexible sleeve or tube that is filled with oil and sealed. The oil provides a means for coupling the pressure wave arriving at the hydrophone through the sleeve and to the individual elements.
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| USGS Analog single-channel hydrophone streamer stowed on deck of the research vessel. |
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In order to minimize noise incoming to the streamer, there are three main considerations; source-receiver geometry, tow depth, and ship-receiver geometry. The streamer is towed separate from the sound source and at a position, usually somewhat to the side, which minimizes ship noise (electrical and mechanical). Tow depth is important, so that sea-surface energy reflections do not mask the incoming signal (Mosher and Simpkin, 1999). Also, the head and tail of the streamer design are tailored to minimize noise from strumming (noise produced by the tow cable) and from whipping action, respectively (Sylwester, 1983).
References
Mosher, D.C. and P.G. Simpkin, 1999, Status and Trends of Marine High-Resolution Seismic Reflection Profiling: Data Acquisition, Geoscience Canada, V. 26 (4), p. 13.
Sylwester, R.E., 1983, CRC Handbook of Geophysical Exploration at Sea, Richard Geyer and J. Robert Moore (Eds.), CRC Press Inc., Boca Raton, FL, p. 109.
