Almost 1,000 kilometers from the Thai coast devastated by the 2004 tsunami, engineers plunge a detection buoy into the sea, an essential link in a prevention system intended to ensure that such a deadly disaster does not happen again.
On December 26, 2004, a magnitude 9.1 earthquake at the bottom of the Indian Ocean triggered a gigantic tsunami that killed around 230,000 people in around ten countries in South and South-East Asia.
Dozens of detection buoys
At the time, prevention systems were rudimentary and it was impossible to warn the millions of people living on the coasts of the Indian Ocean in advance.
In the years that followed, several governments came together to develop a global tsunami information system, drawing on a network of six detection buoys in the Pacific established by the National Oceanic and Atmospheric Administration of the UNITED STATES.
A battery change every two years
Known as Deep-Ocean Assessment and Reporting of Tsunami (DART), the system now has 74 buoys around the world.
Each of them floats on the surface while attached to the seabed. The buoys monitor signals from a seismic sensor placed far below, as well as changes in water level.
Installed in some of the harshest working environments on earth, these battery-operated buoys need to be replaced every two years. Currently, only 50 of them are operational, but the network was designed to ensure coverage in all cases.