The extreme low-frequency infrasonic hydrophone, with associated software, is capable of sensing down to .0001 Hz — a 4.999-Hz improvement from current similar systems. This ultra-low-power-consuming hydrophone also isolates and removes significant amounts of background noise inherent to the electret-type microphone not previously introduced into hydrophone applications.

The uniquely robust unit design also permits sub-freezing operations deep below the surface. The results promise to drastically alter lives and multiple industries, enabling totally new data for weather monitoring and earthquake/ tsunami prediction, among numerous other applications. It could also improve current hydrophone accuracy or reliability in finding oil resources and will enable monitoring of human-generated infrasound in water.

The hydrophone boasts unprecedented capability for precise detection as proven in testing, where it sensed wave range between surface waves and tidal surges with periods between .3 and 30 seconds, or 3 to .033 Hz. The technology uses a back-electret microphone, inherently reducing noise, in a stainless steel body. The stainless steel diaphragm conducts infrasound well and the material's robust nature and internal configuration facilitates sub-freezing and deeply submerged sensing of sound down to .0001 Hz.

With an appropriately spaced array of three hydrophones, it is possible to determine the direction of origin of a submerged infrasonic source; the addition of one more in another location will also enable determination of the precise location of origin.

The oil industry uses existing infra-sound systems to locate undersea oil deposits and this technology could potentially improve the accuracy or reliability of current practices. It could also be used to give tsunami and earthquake warnings, monitor ships, and generate electrical energy from infrasound. This technology has potential to unlock new industry uses not currently understood due to the unprecedented nature of its capabilities.

NASA is actively seeking licensees to commercialize this technology. Please contact NASA's Licensing Concierge at This email address is being protected from spambots. You need JavaScript enabled to view it. or call us at 202-358-7432 to initiate licensing discussions. Follow this link here  for more information.


Tech Briefs Magazine

This article first appeared in the May, 2021 issue of Tech Briefs Magazine.

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