Mud volcano Set to Erupt for Quarter-Century !

matanews.com : Lapindo Brantas Mud

A mud volcano that has displaced more than 13,000 Indonesian families will erupt for at least a quarter of century, emitting belches of flammable gas through a deepening lake of sludge, scientists reported on Thursday.

Underground pressure means the volcano "Lusi," in Sidoarjo, East Java, is likely to gush grey mud until 2037, when volumes will become negligible, according to their computer model.

But gas will continue to percolate through it for decades and possibly centuries to come.

"Our estimate is that it will take 26 years for the eruption to drop to a manageable level and for Lusi to turn into a slow bubbling volcano," said team leader Richard Davies, a professor of Earth sciences at Durham University, in northeast England.

Thirteen people were killed after Lusi erupted on May 29 2006.

Mud volcanoes can form in two different ways. New fractures in rock that caps mud deposits can open, allowing the mud to rise to the surface if it’s under pressure. Or, an earthquake can liquefy mud that then travels through pre-existing cracks to the surface. (NASA Images - wired.com)

At its height, the volcano gushed 40 Olympic-sized pools of mud each day, a rate that has now slowed to four per day, Davies said by phone.

Its lake of mud has now smothered 12 villages to a depth of up to 15 metres (nearly 50 feet) and forced around 42,000 people from their homes.

The computer simulation is based on data from two existing commercial gas wells in the same region and on seismic reflection data that gives a picture of Lusi's geological structure.

"In the middle of the lake, or the volcano, is a vent that is 50 metres (164 feet) wide but there are 166 other vents that have popped up over the last four-plus years," said Davies.

"These have popped up in factories, in roads, in people's houses. Some of them have ignited, there have been examples of people being hurt by flames that have been formed due to the ignition."

Lusi's staying power means it will be a long-term but gradually less dramatic menace, he warned.

"You can't return to the area. In fact, ultimately, probably the impact of the volcano will increase," Davies declared.

"I think we've seen the most dramatic destruction. But it's not the end of the story. These vents are still forming."

The area is also slowly subsiding, and by 2037 could have formed a depression 95-475 metres (312-1558 feet) deep.

The Indonesian government blames the eruption on an earthquake that struck days before, about 280 kilometres (174 miles) away from Lusi.

But foreign experts accuse a gas drilling company, Lapindo Brantas, of failing to place a protective casing around a section of its well.
As a result, the well hole was exposed to a "kick" from pressurised water and gas that lie beneath the layer of mud, thus driving the grey, concrete-like fluid to the surface.

The study is released in the London-based Journal of the Geological Society.

A new analysis shows that a deadly mud volcano in Indonesia may not have been a natural disaster after all. The research lends weight to the controversial theory that the volcano was caused by humans.

AP Photo/Trisnadi

Villagers near Sidoarjo noticed a mud volcano beginning to erupt at 5 a.m. local time May 29, 2006. It was about 500 feet from a local gas-exploration well. Every day since then, the Lusi mud volcano has pumped out 100,000 tons of mud, or enough to fill 60 Olympic-size swimming pools. It has now covered an area of almost 3 square miles to a depth of 65 feet. Thirty thousand people have been displaced, and scientific evidence is mounting that the company drilling the well caused the volcano.

“The disaster was caused by pulling the drill string and drill bit out of the hole while the hole was unstable,” said Richard Davies, director of the Durham Energy Institute and co-author of a new paper in the journal Marine and Petroleum Geology, in a press release. “This triggered a very large ‘kick’ in the well, where there is a large influx of water and gas from surrounding rock formations that could not be controlled.”

Mud volcanoes can form in two different ways. New fractures in rock that caps mud deposits can open, allowing the mud to rise to the surface if it’s under pressure. Or, an earthquake can liquefy mud that then travels through pre-existing cracks to the surface.

Davies argues that the “kick” fractured the rock in the area, opening up new pathways for pressurized mud to come flowing up to the surface. Davies’ team’s research uncovered new evidence from a drilling log that the drilling company, Lapindo Brantas, pumped drilling mud down their well to try to stop the mud volcano.

“This was partially successful, and the eruption of the mud volcano slowed down,” Davies said. “The fact that the eruption slowed provides the first conclusive evidence that the bore hole was connected to the volcano at the time of eruption.”

The new paper came in response to a paper published by the company’s lead driller in the same journal. Lapindo Brantas has long maintained that drilling did not cause the eruption. Instead, the company claims an earthquake that occurred two days before and about 175 miles away did the damage. Obviously, there are financial ramifications if the drilling company is found liable for the disaster.

• The problem with the earthquake hypothesis is the stress changes caused by the quake would have been relatively small, too small to cause the volcano, said Davies’ co-author, University of California at Berkeley geologist Michael Manga.

• “There is 1,000 times not enough energy to cause the eruption,” Manga said. He was drawn into the controversy when the drilling company cited one of his papers on how earthquakes can cause mud volcanoes and have on 32 occasions. But Manga noted that based on all the historical examples that scientists have, what the company claimed happened was impossible.

“So I wrote a one-page paper [in 2007] saying it could not possibly have caused the mud volcano,” he said.
Other scientists came to similar conclusions, although some doubts remained.

An even stronger piece of evidence that the earthquake could not have created the mud volcano, Manga said, is that in the years before the quake, there were “bigger and closer earthquakes that did not cause an eruption.”

In fact, the stress changes associated with the tides are larger than the stresses caused by the earthquake that happened to strike two days before the mud volcano eruption began.
Still, the editor of the journal in which both the company’s paper and the Manga-Davies rebuttal was published said that it was possible that the same data could be subject to multiple interpretations.

“In geology, sometimes it’s not about being right or wrong, it’s about being reasonable or unreasonable,” said editor Octavian Catuneanu, geologist at the University of Alberta. “The funny thing is that sometimes datasets can be interpreted by different people in different ways, and this leads to arguments and controversies.”

Still, there is a large financial incentive for Lapindo Barantas’ scientists to find that their company was not responsible. “The drilling company cannot say anything different, right?” Manga said.

But Catuneanu said that no matter who the scientists were working for, they still had to meet the scientific standards of the journal.

“I guess there would be some bias there, but as a journal editor, what I need to make sure is that the authors of an article stick to the science,” he said. “If they want to have something publishable, they have to bring data and discuss it in a scientific manner.”

Lapindo Barantas could not be reached for comment.

-terradaily.com | www.wired.com/wiredscience/2010/02/mudvolcano/