A tsunami wave in deep water creates a small but measurable change in pressure that will be maintained for as long as twenty minutes. By monitoring any such changes, subsea detectors can be used to trigger an alarm that sends a warning message to a buoy-mounted receiver on the surface. The buoy, in turn, relays the message via a satellite data link to a control centre that can issue a warning to vulnerable communities.

The Sonardyne tsunami detection system is based on a Compatt 6 subsea transponder that uses the latest Wideband acoustic signal technology to provide robust through water communications in difficult acoustic conditions. Compatt 6s are used extensively in the oil and gas industry where their reliability is regularly trusted for use on the most complex construction survey projects.