Sonardyne UK (Head Office)
T. +44 (0) 1252 872288
F. +44 (0) 1252 876100
E. sales@sonardyne.com
www.sonardyne.com
Datasheet
Tsunami Detection System
Description
The Tsunami Detection System can
be deployed on the seabed in the
deep ocean from where it will
monitor the pressure of the water
above it. 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, the subsea detector will
trigger an alarm that sends an
acoustic warning message to a buoy-
mounted transceiver on the surface.
The transceiver, in turn, relays the
message via a satellite data link to a
control centre.
Sonardyne’s tsunami system is based
on the company’s successful Compatt
5 seabed acoustic transponder. It
uses the latest Wideband™ digital
acoustic technology to provide robust
through water communications in
difficult acoustic conditions.
The Compatt 5 may be deployed in
water up to 7,000 metres and it is
fitted with a sensor that continuously
monitors water pressure, saving data
every fifteen minutes. Because a
reliable early warning of a tsunami
can only be obtained close to the
sea floor, the Compatt provides the
essential means of sending these
readings up to the surface.
Every hour the Compatt converts the
pressure readings into signals which
it transmits acoustically to the buoy
on the surface. The satellite
communications transceiver on the
buoy then automatically forwards the
pressure readings to the tsunami
monitoring agency ashore. The
system can also receive data from
the central control so that revised
monitoring parameters can be
downloaded to the Compatt if
required.
The Compatt is programmed to
anticipate continual changes in the
pressure of the water as these can be
caused by influences such as tides,
weather conditions and temperature.
Because such changes can be
predicted, a variation of as little as
3cm from the expected pattern will
switch the device into Tsunami Alert
Mode. This will cause the Compatt to
immediately transmit any data that
has been saved during the past hour
to the surface. It will then take
pressure readings every fifteen
seconds which it will immediately
send up to the buoy for transmission
by satellite to the monitoring station.
This means that the first warning of a
tsunami, caused by a small variation
in water pressure on the seabed
thousands of miles from shore, can
be in the office of the monitoring
organisation within minutes.
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