Seismic and hydroacoustic sensing of infrasonic noise in coastal waters
Three-component ocean-bottom seismometers with radio links have been deployed in coastal waters to investigate natural and man-made noise at extremely low frequencies. Seismograms from one or up to three sensor stations are analyzed in terms of amplitude and cross-spectra at frequencies between 1 and 18 Hz. Examples of area dependence and wind dependence are given, and the underlying propagation mechanism is investigated. Finally ship-radiated noise is used to demonstrate the directional selectivity of those sensor units.
SourceIn: Underwater Ambient Noise (SACLANTCEN Conference Proceedings CP-32), Vol. 2, Part 1, 1982, pp. 5-1 - 5-12.