By Indonesia correspondent Anne Barker
Residents fear more than 1,000 people have died in one rural village
The tsunami never reached Balaroa and Petobo; the towns are believed to have sunk due to liquefaction
In Petobo, many of the area's 744 houses have disappeared
The final death toll from last week's devastating earthquake and tsunami in Indonesia might never be known.
The village with possibly the single highest death toll in Sulawesi may well be turned into a mass grave because of the difficulty of digging out bodies.
Balaroa virtually disappeared into a sinkhole after the earthquake struck and residents fear as much as 70 per cent of the population there has been killed.
The rural village — a few kilometres outside Palu — was home to about 2,000 people until Friday.
Search and rescue workers using earth-moving equipment have toiled for days to find survivors.
But with more than 1,000 people still missing, it could well prove to be an impossible task.
Instead the village would become an unmarked grave, with the same earth movers eventually used to bury the village permanently.
Many of Balaroa's 1,747 houses appear to have sunk into the earth. All that remains of some of the houses are little more than the rooftops sticking out of the ground.
About 600 people have been confirmed dead in the village, but another 1,000 are officially missing. As few as 200 may have survived.
Nurhayati, 46, was visiting neighbours with her husband Denrate when the earthquake struck.
She says she yelled at her husband to get out but lost him in the ensuing chaos.
"Suddenly the wall cracked," she said.
"I ran away first. I thought my husband was behind me. Then the earth jolted.
"And by the time I reached a safer place I looked back and he wasn't there."
Nurhayati says she has looked for her husband for five days but can't find him. She still hasn't told her son that his father is probably dead.
"Only when I find my husband will I tell him," she said.
"He still doesn't know what happened to his father."
Hari, who lives near Balaroa, described the unusual sinkhole effect that effectively swallowed the village after the earthquake struck.
Sutopo Purwo Nugroho, a spokesman for Indonesia's national disaster mitigation agency, says the sinkhole phenomenon at Balaroa — and nearby Petobo — was caused by a process known as liquefaction that took place underground.
"When the quake hit the layers below the surface of the earth became muddy and loose," he said.
"The soil in Balaroa was actually moving up and down, with houses rising up two metres and roads going down five metres since they were built near the Palu-Koro fault and the quake triggered liquefaction."
The liquefaction process appeared even more extreme at Petobo, a smaller village that has been effectively buried in a deep mud sludge, resembling quicksand.
Many of Petobo's 744 houses have disappeared.
Houses here appear to have sunk into the mud up to their roofs. Cars and motorbikes stick out at odd angles. The village's main road is impassable.
At first glance it appears Petobo must have been hit by the tsunami bringing mud instead of water into the village.
But Petobo is too far inland, and Mr Nugroho blames the same process of liquefaction that occurred at Balaroa.
One Petobo resident, Aswar, said he was not home when the earthquake struck. He later went to check on his house but could not find it.
"The mud flattened the house. I don't know where the house is anymore," he said.
"All the walls and roofs are gone. I can only see one of the cupboards standing there."
Indonesia's search and rescue agency, Basarnas, was at Petobo on Wednesday beginning the slow task of clearing the road into the village. About 200 bodies have been retrieved.
But like Balaroa, the village of Petobo may prove too difficult to recover, or dig for every dead body, and instead may remain permanently uninhabitable.
It seems a particularly cruel fate for survivors.
Residents who have already lost one or multiple family members in the quake — as well as their homes — could face the loss of their land if it proves too hard to restore.
- Australian Broadcasting Corporation
- © ABC