Indonesian officials have revealed significant holes in the tsunami warning system as the death toll from Monday’s tsunami climbed to more than 400.
Hopes are fading for more than 300 others still listed as missing after the huge wave, triggered by a powerful earthquake, struck the Mentawai islands off the west coast of Sumatra.
After the Boxing Day tsunami killed more than 230,000 people around the Indian Ocean in 2004, a string of sensor buoys was distributed off the Indonesian coast.
But survivors said they had almost no warning that the three-metre wall of water was bearing down on them, despite the alarm buoys.
Riduan Jamaluddin, the deputy chairman of the agency responsible for managing the buoys, says most of them are not working.
He says initial plans for 22 buoys were scaled down to 12.
In the wake of the tsunami which struck the Mentawai Islands this week, he has revealed that only three or four have survived technical problems and vandalism.
The buoys are not critical to the Indian Ocean warning system, but the gaps in the chain will probably cause a delay in alerts about future tsunamis.
An official tsunami warning was issued after Monday’s 7.7-magnitude quake, but it either came too late or did not reach the communities in most danger.
Meanwhile, on the island of Java, a volcano, which this week killed 32 people, again spewed ash and deadly heat clouds.