Amir Tejo, Surabaya – More than $30 million worth of infrastructure relocated because of the three-year-old Lapindo mudflow in East Java may be once again under threat, this time from an expanding underground fissure, the Sidoarjo Mudflow Mitigation Agency said on Sunday.

Achmad Zulkarnain, a spokesman for the agency, also known as BPLS, said a subterranean-penetrating radar device had detected an increase in the dimensions of a crack caused at the time of the Lapindo mud flow disaster in Porong, Sidoarjo. The fissure is reportedly extending towards an area previously claimed to be safe and where the infrastructure, which includes a toll road and railway, had been relocated.

This latest crevice opened up in Pamotan village, 500 meters from where a new section of the Porong toll road was being constructed because the original road had been engulfed by the mud. "The crack is growing rapidly every day. Given time, it could reach the new toll road," Zulkarnain said.

Data collected by the radar device in 2008 had convinced the BPLS that the fissure would not reach Pamotan village and disrupt the construction off the relocated toll road, railway track and other thoroughfares.

However, similar measurements this year are telling another story. "The fissure is approaching the infrastructure relocation site, which has already cost Rp 300 billion for land and building acquisition," Zulkarnain said.

The BPLS chairman, Sunarso, said his agency could only report the finding to the government. "As an executive body, we don't have the authority to make any decision about moving the infrastructure relocation site," he said. "That authority lies with the government."

Sunarso said he predicted the government would find it hard to secure another site, since the current area had been prepared far in advance. "Construction of the new infrastructure is under way even now," Sunarso said.

BPLS plans to send a team of geologists to check the magnitude of the threat brought on by the fissure and land subsidence in Pamotan. The team's findings will be attached to a BPLS monthly report to the government.

"BPLS will submit data on the subterranean damage in Pamotan," Sunaro said. "Whether or not the infrastructure relocation will continue at the same site depends on the government."

The replacement infrastructure consists of a 7-kilometer arterial road and 10 kilometer of toll road and railway track stretching from Tanggulangin in Sidoarjo to Gempol in Pasuruan, past Pamotan village.

The total road and railway is 120 meters wide – 50 meters for the toll road and 20 meters for the railway track, which are flanked by two arterial roads, each 25 meters in width.

The damage caused by the mudflow, which has been devouring land and homes in Sidoarjo district since May 2, 2006, has been estimated at about $4.9 billion and growing.

The mud volcano has so far buried 12 villages, killed 13 people, displaced more than 42,000 residents and wiped out 800 hectares of densely populated farming and industrial land.

Curtin University of Technology's Dr Mark Tingay, who visited the disaster site in June this year, said about 100,000 people remained under threat from subsidence three years after the volcano first erupted.

"The high flow-rate may only continue for two to three years, or it might continue for hundreds of years," Tingay said. "And like other mud volcanoes, it will probably be in existence for thousands of years, even if its flow-rate subsides," he added.