Tsunami Detection Buoys Help Safeguard Lives in Thailand

Country's Two Devices Linked by Satellite to Towers That Can Raise Alarm in Coastal Areas in Minutes

ANDAMAN SEA, Thailand - Almost 1,000km off the Thai coast devastated by a tsunami 20 years ago, engineers lower a detection buoy into the waves - a key link in a warning system intended to ensure no disaster is as deadly again.

On Dec 26, 2004, a 9.1-magnitude earthquake under the Indian Ocean triggered a huge tsunami with waves up to 30m high.

Only a rudimentary warning system was in place at the time, with no way to alert the millions of people living around the Indian Ocean. Almost 230,000 people were killed in 14 countries.

In the years following the disaster, multiple governments developed a global tsunami information system, building on the US National Oceanic and Atmospheric Administration's network of six detection buoys in the Pacific.

Known as Deep-Ocean Assessment and Reporting of Tsunamis (Dart), the system now has 74 buoys around the world.

Each floats on the surface while tethered to the seabed, monitoring signals from a seismic sensor on the ocean floor and changes in the water level.

Installed in some of the toughest working environments anywhere on the planet, the battery-powered buoys must be replaced every two years. Only 50 of the devices are currently operational, but the network has been designed to provide coverage regardless.