A tsunami wave in deep water creates a small but measurable change in pressure that will be maintained for as long as 20 minutes. By monitoring these changes, information can be provided early enough to be used as part of a warning system for coastal communities that are vulnerable to tsunamis.

Long-term reliability of these systems is essential. The system might not be heard from for years, but when shore tsunami warning centres receive an alert, they want it to be received within a useful time-frame and to know that the information it offers is reliable.

Our Tsunami Detection System is a customised version of our highly successful acoustic Compatt 6 transponder, and has our Wideband®2 digital acoustic technology to provide robust data transmissions, even in difficult acoustic conditions.

Operating in the LMF (14 – 20 kHz) band, the system is supplied with a buoy-mounted transceiver, but can also support telemetry with any of Sonardyne’s compatible surface dunkers or transceivers. This two-way link also enables the unit to be remotely configured.

At the heart of the instrument is a Bottom Pressure Recorder (BPR) that continuously monitors water pressure. It saves and transmits data, at set intervals, while also running an algorithm which compares the measured pressure with pressure predictions correct for local conditions. If two consecutive differences between the two exceed three centimetres, the instrument goes into an alert mode causing it to transmit a sequence of messages containing high resolution pressure data to the surface over the next few hours.