Some time in the next few decades, the Indonesian city of Padang will cop the "big one" — an earthquake in the Sunda Trench 200 kilometres offshore with enough power to bring into being a tsunami 20 metres high. Within 30 minutes the wall of water will have hit the shore. It will cross the beach and flood onto a coastal plain that houses a million people — 300,000 of them living less than five metres above sea level, mostly in single-storey dwellings.
Many buildings will already be damaged from an earthquake geologists say could register 8.8 on the Richter scale, the earth vibrated into liquid and the roads rendered impassable. The wave will pick up this debris and use it to scour the landscape. The wave will travel one kilometre inland — even further along the three rivers that drain water from the mountains to the sea.
All these things we know because the massive fault line that lies just off Padang, the capital and largest city of the province of West Sumatra, is one of the most intensely studied in the world. It's where the Indo-Australian tectonic plate, which is moving northwards, collides with the Sunda plate and passes underneath it. For 200 years since the last big one in 1797, in a spot just off Padang, one area has been "stuck", with pressure building.
Smaller earthquakes in the area, including one in 2009 that killed 1200 people in Padang, have only increased that pressure. When it suddenly comes "unstuck" - a process due to happen about now - the damage will be catastrophic.
"In geological terms, it's imminent," says Trevor Dhu, the risk and vulnerability manager at the Australian-Indonesian Facility for Disaster Reduction.
So with all this advance notice, surely the people of Padang, the 16th largest city in Indonesia, are prepared? The answer, in short, is no. A recent visit to this city on the edge of disaster revealed that its residents have neither the "hardware" (safe buildings and places to evacuate to) nor the "software" (education and knowledge) to survive the coming catastrophe.
The Australian aid program, AusAID, with the Indonesian government are trying to provide both but in the face of massive ignorance, poverty and occasionally superstition, it's an uphill battle. The lack of knowledge, or even conversation about earthquake is striking, considering the danger.
Eric Kurniawan is training to be a dentist, so is better educated than most of Padang's residents. But when I showed him an inundation map of his city, he visibly blanched. It was the first he had heard of the danger of earthquake and tsunami.
Kurniawan's family lives in a place deep in the "red" zone, but he had no idea of the risk, nor what to do if a big wave came. Weeks after we met he contacted me again saying: "I am scared."
"In certain areas people still believe that, if you talk about a tsunami, it will happen," says Patra, an organiser with local disaster education group Kogami.
She is trying to get earthquake safety put on the region's school curriculum, but is frustrated by a lack of interest at the government level. They say the children already have enough to learn.
The SDN 02 Lubung Alung school is north of the city and out of the tsunami zone, but it's still well within the range of an earthquake. Principal Zulbaiti Kamil boasts that the children have done an evacuation drill "already 10 times" since the 2009 quake.
But ask the children themselves what they would do if their building started shaking and their faces go blank. Finally, one little girl, Maulidian Nurul, ventures: "We have to get out of the building to an open field."
She's right, but she seems to be the only one who knows, even though many of these children still live in the remnants of homes damaged by an earthquake just four years ago.
"This year we haven't done any drills," admits the principal later. "I rejected that activity because there was already too many. It was disrupting classes."
The earthquake in 2009 was too deep to be the big one, and it did not happen in the heart of the fault line. Still, it killed about 1200 people and severely damaged or destroyed about 140,000 houses and 4000 other buildings.
A bit further down the road from the school, a young farmer, Yaldi, is intent on his work, bending pieces of strong, reinforcing wire into shape. Yaldi lives with his mother, Sias, 56, and younger sister, Yeni, 15. With the help of an AusAID education and funding program, he is rebuilding his home to withstand the coming tremblor.
"It's a safety house. A quake safety home," he says proudly, demonstrating how the wire reinforcing goes into the building's concrete substructure.
The family house was severely damaged in 2009 and his mother particularly was traumatised. They lived in a tent for a while, and then moved back into the damaged building, avoiding the most unstable rooms, until they could afford to rebuild.
The house next door is also being rebuilt. But it looks decidedly less sturdy. It's owned by Yaldi's aunt, Pik Manih — his mother's sister. In Padang's matrilineal society, it's the women who own the land and make decisions about it, and these sisters live on the land once owned by their mother.
At Pik's house, her husband has made some attempts at reinforcement, but the wire is too thin, the bracing too far apart. The roof simply sits atop the walls, without being joined as it should be; one wall is made of unstable river stones set in mortar.
Pik says "of course" she is worried that the new house will fall down in an earthquake, as the old one did. "It's not finished yet and we're still living in a wooden house behind this one, but ... even when we've completed this one, it doesn't feel any safer."
Building an earthquake-safe house is more expensive and takes more skill than building in the old style. Aid helps educate people in how to "build back better" and provides grants based on individuals meeting performance targets.
But many, like Pik's husband, are ignoring the advice, rebuilding using the old, cheaper methods, largely funded by no-strings-attached money from the national government.
A report commissioned by AusAID found last year that: "There is a high level of indifference for, and no social or political pressure for promoting or supporting safer building techniques."
Six construction techniques are needed to create better housing, and most in Padang had used none of them. Only eight out of 3000 family heads interviewed had applied all six.
"The most mentioned barrier to building safely is lack of money," the report found. Most people in this poor country had very little money and what they managed to save went to pay school fees.
According to Patra at local organisation Kogami, the most important safety measure is education, and the biggest barrier is the "mindset of the government".
"Instead of having a government program, we have to go from one school to another, talking to each principal, to convince them to put in place the curriculum," she says. Of the 200 schools in the "red zone" her group has visited perhaps 70.
Indonesia is one of the most disaster-prone nations on earth, but disaster management is a relatively recent concern. Jason Brown, who is responsible for training and outreach at the Australian-Indonesian Facility for Disaster Reduction, says the message is starting to get through, at least at the official level.
Indonesia's Minister for Disaster Mitigation, Syamsul Maarif, was in Padang recently outlining the government's new master plan and told Fairfax Media it included an ambitious scheme to build "vertical evacuation" — high structures on the coastal plain that people can go up to avoid inundation in a tsunami.
With 2000 to 3000 people per shelter, Syamsul says the government would need to build perhaps 150 shelters.
He also recognises the need for education, he says, and funding for these measures will start becoming available in next year's national budget.
But in a land where ignorance is bliss and promises often exceed delivery, the people of Padang should hope that the big one does not hit quite yet.