Dictionary:Hydrophone
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A detector that is sensitive to variations in pressure, as opposed to a geophone that is sensitive to particle motion. Used when the detector can be placed below a few feet of water, as in marine or marsh work or as a well seismometer.
Some hydrophones operate because of magnetostriction (q.v.) but most are piezoelectric (q.v.). Piezoelectric hydrophones include benders, disc hydrophones, and cylindrical hydrophones.

The sensing element is usually a piezoelectric ceramic material such as barium titanate, lead zirconate, or lead metaniobate. Piezoelectric hydrophones are high-impedance devices and signals may be passed through preamplifiers or impedance-matching transformers before transmission through the streamer to the recording instruments. Compare geophone.
References
- ↑ Sheriff, R. E; Geldart, L. P (August 1995). Exploration Seismology, 2nd Ed. Cambridge Univ. Press. p. 224. ISBN 9780521468268.