The QUEphone is a new generation of autonomous
hydrophone with a built-in satellite modem and GPS receiver. It is a stand-alone
instrument without mooring cables that once deployed it repeats dives and
ascents while monitoring the sound in the deep ocean for an extended duration. Upon
a detection of a sudden major acoustic events, such as an increase of volcanic/seismic
activities or calls of marine mammal of endangered species, it returns
to the surface and transmits data back to land so that scientists can evaluate
the results in near real-time.
Spectrogram of the ambient acoustic signal recorded
by the QUEphone at Axial Volcano in the Northeast Pacific in 2006.
Whale calls, ship, and ROV noises are present. A T-wave (water-borne earthquake signal)
was also seen at 3.5kseconds, which was later identified as a 3.5
earthquake originated in Gorda Ridge off California.