BANDA ACEH (REUTERS) - Mr Arif Munandar had been pronounced dead before he woke up in a body bag four days after a monstrous wave swept his village in Indonesia's northern Aceh province 15 years ago.
When a 9.1-magnitude quake opened a faultline deep beneath the Indian Ocean on Dec 26, 2004, it triggered a tsunami as high as 17.4m, killing more than 230,000 people in Indonesia, Sri Lanka, India, Thailand and nine other countries.
Aceh province bore the brunt of the disaster. A total of 128,858 people were killed there, according to statistics compiled by the government and aid agencies. Another 37,087 are still listed as missing.
Mr Munandar, who spent six years living in a relief camp before he was able to complete the rebuilding of his old house with government help, lost 24 family members, including his wife and three children. He has since remarried and has two children.
Now, the 49-year-old works as a radio communication technician at Aceh's disaster mitigation agency, and considers it his personal mission to keep his village's tsunami warning system well-maintained.
"We need to provide information to the community in order to minimise the number of casualties when such a disaster happens again," said Mr Munandar, stressing the need to anticipate the worst.
More than US$400 million (S$542 million) has been spent across 28 countries on the early-warning system, comprising 101 sea-level gauges, 148 seismometers and nine buoys.
"The Indian Ocean region is much safer against the tsunami threat than it was in 2004," said Mr Srinivasa Tummala, head of the Indian Ocean Tsunami Warning and Mitigation System which was established in 2013.
However, a lack of sufficient tsunami buoys, other detection equipment, and real-time data-sharing, as well as the difficulty of maintaining the tsunami detection system, remain the biggest hurdles, he said.
Threats like the twin tsunamis triggered by underwater landslides in Indonesia's Palu and Banten province last year, which hit the shore in a shorter timeframe, also continue to challenge the early warning system, Mr Tummala added.
Experts are exploring new technologies such as mobile apps and a Global Navigation Satellite System network to enhance preparedness.
The focus of the tsunami warning mitigation system is now on community readiness, Mr Tummala said, including carrying out regular drills.
In the coastal Ban Nam Khem village, in southern Thailand, which lost more than half its population in the 2004 tsunami, the national anthem is played weekly on the tsunami warning tower as a form of test run for a nightmare they hope will never recur.
"The tower shouldn't be used just for warnings about a tsunami," said village community leader Prayoon Chonkraichak.
"It should be utilised for more purposes so that it's worth the budget, and more importantly, so people in the community can have more confidence in it," he added.