When 12-metre (39 ft) waves slammed into Banda Aceh on the northern tip of Indonesia's Sumatra island on Boxing Day in 2004, Arif Munandar lost his wife, three sons, and 20 other members of his family as much of the city was obliterated.
The tsunami - triggered by a massive 9.1 magnitude quake - also hit at least six other countries along the rim of the Indian Ocean, killing more than 230,000 people. Indonesia was hit hardest, with more than 168,000 killed.
Fifteen years on, Munandar and tens of thousands of others have been allowed to rebuild in the same low-lying areas of Banda Aceh despite continuing risks of tsunami and other coastal hazards like flooding, Reuters found. Officials and experts say it's because of lax law enforcement, a lack of government resources for relocation, and an entrenched reluctance on the part of many survivors to abandon their lives and livelihoods near the coast.
More than 25,600 residential, commercial, government and school buildings are inside the high-risk area, which was almost completely wiped out in 2004, according to a Reuters analysis of city data. City officials say about 50,000 people live there today - nearly the same as in 2004.
Immediately after the disaster, the government considered banning construction within a two-kilometer (1.2 mile) coastal buffer zone. But the plan was dropped after communities, many dependent on fishing, took to the streets to protest such attempts to move them away from their ancestral lands and livelihoods.
Survivors like Munandar, who received around 25 million rupiah ($1,700) each in reconstruction aid, rebuilt in the hazard zone. The government spent 2.2 trillion rupiah rebuilding 25,000 houses throughout the city, including inside the hazard zone, according to officials.
Srinivasa Tummala, an oceanographer who heads the Indian Ocean Tsunami Warning and Mitigation System, says governments in Indonesia and the region need to do more to control coastal populations and prepare communities by holding regular tsunami drills, marking out evacuation routes, constructing shelters, and enforcing minimum building standards.
"Realistically, there needs to be both stricter enforcement and building community resilience," Tummala said.
Jalaluddin, head of the public works and spatial planning department in Banda Aceh, said that since foreign aid had dried up the city government no longer had the funds needed to relocate residents or create seawalls near the coast.
Even where building codes and zoning laws existed, there was little urgency to enforce them now that the 2004 disaster was 15 years in the past, and stronger structures were expensive to build, he said. This meant most buildings did not meet minimum standards to withstand earthquakes or strong waves.
"All we can do is ... build facilities like evacuation buildings and conduct evacuation drills," Jalaluddin, who goes by one name, told Reuters. "If the public wants to stay on in high-risk zones, we must find engineering solutions to withstand disasters."
The government had informed people of the risks of living in danger zones by adding disaster preparedness to the school curriculum, through public service announcements, and by enlisting the help of volunteers and religious leaders to conduct tsunami drills.
Indonesia, which straddles the seismically active area known as the Pacific Ring of Fire, is one of the world's most disaster-prone countries, research shows. Since 1900, at least 26 fatal tsunamis have struck Indonesia - 14 of which killed more than 100, according to a database maintained by the U.S. National Oceanic and Atmospheric Administration.
Even so, the 2004 tsunami was an event with little regional precedent and caught countries unprepared. Outside Indonesia, about 40,000 people were killed in Sri Lanka, and 5,395 people in Thailand, among them about 2,000 foreign tourists. Both of those countries also have allowed rebuilding.
"These are random phenomena, but it is important to communicate that while they might be infrequent, their impact can be huge. There is so much uncertainty in predicting how large such events can be ... that it is better just to be prepared," said Finn Lovholt, a tsunami specialist and principal scientist at the Norwegian Geological Institute.
Since 2004, countries like Indonesia, Sri Lanka, and Thailand have taken pains to educate people about coastal hazards like tsunami, storm surges, and flooding. Governments have collectively spent millions on a regional early-warning system, evacuation routes, beachfront sirens, and tsunami drills.
But a terrifying reminder of Banda Aceh's under-preparedness came in 2012, when an 8.6-magnitude quake struck at sea. Thousands of residents shunned shelters and fled by car and motorcycle, clogging streets with traffic, while a network of powerful warning sirens stayed silent because they were broken. No waves came, but the event showed how unprepared the country was for another disastrous tsunami.
For residents like Munandar, there is often little choice but to stay in high-risk areas. He lived in a camp for displaced survivors for six years after the 2004 tsunami and could not afford to relocate.
Those who own houses or land in the danger zone find it difficult to sell to others fearful of the risks, while some are reluctant to abandon their communities or what little they own.
"Everyone has trauma from that time but we can't be afraid all the time," Munandar said in the house he rebuilt just 500 meters from the shore. "What we need now is to know how to survive wherever we are because disaster will come without notice."
