Jakarta (AsiaNews/Agencies) – Indonesia has activated the initial phase of a tsunami early warning system off the coast of Sumatra aimed at avoiding a repeat of the devastation caused by last December's quake-triggered tsunami on the island.

Two sets of moored surface buoys and ocean-bottom pressure sensors were activated off western Sumatra on Tuesday by Indonesian and German scientists, Edi Prihantoro, of the Research and Technology Ministry, said.

"The buoys will pick up and transmit data about sea tremors and pressure from the ocean sensor devices. This is part of the government's tsunami early warning system master plan," he said.

Data from the instruments can be up-linked to a satellite and transmitted to a monitoring station near Padang in West Sumatra, Mr Prihantoro said. The information is then relayed to the public through mobile text messages, e-mail, fax and telephone.

"Our next plan is to install the system in the Sunda Strait and off the southern coast of Java," he said. "The more instruments we have the better it will be, but we and the German engineers agreed to have 15 for now," he said, adding that it was hoped they would be sufficient to cover all of Indonesia's coastal areas—particularly the earthquake-prone zones.

Indonesia sits on the Pacific Rim of Fire, where the meeting of continental plates causes high volcanic and seismic activity.

It lacked a warning system when a massive quake hit off Sumatra last December 26, unleashing a tsunami that swept up to 7 km inland and killed 270,000 people.

Fauzi, head of the Technology, Tectonic and Tsunami Department at the Meteorology and Geophysics Agency, said earlier this week that along with the sensor buoys, 25 seismographs were being installed along Sumatra's west coast.

Mr Fauzi said that by 2007 the 15 buoys and more than 100 seismographs, which detect the speed of seismic waves to determine whether there is a risk of a tsunami, would have been installed.

"Data from the seismograph will be analysed and relayed automatically through SMS or e-mail in less than five minutes," he said. "Information from the buoys and tide gauges will come between five to 15 minutes after an earthquake."

The system is to be expanded and integrated into a warning system for endangered regions so that the population can be made aware of an impending disaster within minutes.

Authorities are also developing co-ordinated escape routes and disaster preparedness in areas deemed to be at high risk from a tsunami, Mr Fauzi said.