SIDOARJO, Indonesia — How to tame a mud volcano: try dropping hundreds of giant concrete balls into it.
In recent weeks, using a system invented at the Bandung Institute of Technology, workers have been releasing the balls from a complicated crane-pulley-sling contraption into the steaming vent known to scientists as “the big hole.”
Mud volcano experts are bemused. No one has ever stopped an underground mud flow, they say, least of all with a home remedy like this.
Don’t laugh, said Satria Bijaksana, one of three institute geologists who devised the plan, standing at the rim of a vast, dull-gray sea of mud.
“I’m not just some crazy scientist throwing out wild ideas,” said Mr. Bijaksana, 42, who holds a doctorate in rock magnetism from Memorial University of Newfoundland in Canada. “This is not a joke.”
The mud started gushing from the ground nearly 10 months ago when a shaft probing for natural gas pierced a pressurized aquifer about 9,000 feet underground. Since then about 1 billion cubic feet of mud has spread across two square miles.
The mud has buried 12 villages and 20 factories, inundating roads and rice fields and displacing 15,000 people. It is still flowing, at more than 3.5 million cubic feet a day, and no one can say when it might stop.
“After two months, we realized that this was not stopping,” Mr. Bijaksana said, “so we started trying to figure a way to stop it.”
The idea is to jam the gullet of the geyser with 1,000 or more balls linked together like charm bracelets, in bunches of four, the biggest of them weighing about 175 pounds.
Their mass and friction, as they tangle at the bottom of the shaft, should slow the flood to a manageable ooze, Mr. Bijaksana said. But their shape will allow the mud to seep past, avoiding the pressure that could cause it to burst from the ground elsewhere. “We want to slow it gradually,” he said. “A month, two months, three months. But we don’t want to block it.”
Richard Davies, a geologist at Durham University in Britain and an expert on mud volcanoes, is skeptical. “I don’t think they’re going to stop it with this ball idea,” he said in a telephone interview.
He said the plan could work only if the underground crater were shaped almost perfectly like an hourglass, allowing the balls to accumulate in one narrow space.
“The underground plumbing of a mud volcano, I don’t think, is going to be that simple,” he said.
More likely, he said, the balls would simply disappear, swallowed by a gurgling digestive system of hot mud. He dismissed the notion that some of them could be ejected like cannonballs.
“It’s a bit of a David and Goliath situation,” said Mr. Davies, who visited the site and wrote a paper about the eruption this year. “You’re plunking these balls into a vent that is 700 meters deep and the upper part 50 meters wide,” or about 765 yards deep and 55 yards wide. Recently, officials have reported a decrease in the volume of the flow after the insertion of nearly 400 balls.
But the volcano has fluctuated since the start, and Mr. Bijaksana said it was too early to know if his system was working.
Not only scientists have doubts about this approach.
Chief Sgt. Sumarono, a soldier stationed at the team’s media center, told The Jakarta Post that local soothsayers had said spirits who lived in the crater would be angry after being hit by the giant concrete balls.
“The mud explosion happened because the spirits in the crater are angry,” said Sergeant Sumarono, who like many Indonesians uses only one name.
“The insertion of the balls will only spark more anger. The soothsayers have already said there will be a new and much bigger burst. I believe this.”
Geysers of mud like this are not uncommon, Mr. Davies said, but most are brief and modest, many are under the ocean and few threaten populated areas.
Hundreds occur in Azerbaijan, some in Trinidad and some off the coast of Nigeria, he said. A few small ones in the Mississippi Delta are remobilizing sediment from a mile or so underground.
Most are natural eruptions of pressurized mud, he said, but they can also be released when drilling hits an aquifer far underground, and the water gushes out like a fizzy soft drink.
The mud started flowing here last May 29 during exploratory drilling by an Indonesian gas company, Lapindo Brantas, which is controlled by the powerful welfare minister, Aburizal Bakrie.
The company says it is not at fault, and it blames a major earthquake two days earlier with an epicenter about 190 miles away.
Although some Indonesian scientists have spoken out to support that claim, Mr. Davies said he doubted the earthquake caused the volcano.
Some critics have blamed the company’s failure to insulate part of its drill hole, but Mr. Davies said it was not clear whether that could have prevented the rock from fracturing.
Mr. Davies said he was one of only a few experts on the unglamorous subject of mud volcanoes.
“The igneous ones are the popular ones,” he said. “Mud volcanoes are the poor brother of igneous volcanoes. There are some fairly fundamental things we don’t understand about them.”
Mr. Bijaksana said he and his colleagues were on their own as they took on the volcano, developing their own theories and methods, and their own instruments for dealing with mud.
“If it doesn’t work, should I be worried about what faraway scientists say?” he said.
“People could argue about this over and over again. But this thing is real. We decided to do something.”
