This year, two research teams considered the question—and came to different conclusions. Manga and his colleagues reported in the journal Earth and Planetary Science Letters that there is a 50 percent chance Lusi will last more than 41 years and a 33 percent chance it will last more than 84 years. A team led by Davies had a slightly more optimistic outlook: It suggested in the Journal of the Geological Society of London that the mud volcano’s most likely total life span is 26 years.
In either case, more territory will be swallowed by mud. Further geological analyses might help Indonesian officials better manage the disaster and explain how the recent slowdown in Lusi’s eruptions fits in with the predictions.
The different results emerge from the way the teams modeled Lusi’s plumbing and driving forces. Davies’ team says the water propelling the eruption comes from a 15-million-year-old layer of rock that sits at least 2,000 feet beneath the erupting mud. Twenty-six years, Davies says, is an estimate of how long it will take for the water pressure to return to normal.
Manga’s team says water within the mud layer itself is fueling the eruption. “If we’re right, it’s not typical of most mud volcanoes,” Manga says. Lusi is acting like a can of fizzy soda, he says, with bubbles of carbon dioxide and methane helping bring mud to the surface.
The mud volcano’s recent changes in activity may signal that the mechanism driving the eruption has changed, Davies says, but it’s not yet clear what they mean for the long-term outlook.
This year, scientists who study the eruption met in Indonesia for a conference and to observe the volcano. Instead of belching continuously, Lusi seemed to be “pulsing” every few minutes, Davies says. “It’s a bit like Old Faithful.” It’s also spewing less mud, adds Max Rudolph, a graduate student at UC-Berkeley. At a rate of about 530,000 cubic feet per day, he says, “the current eruption rate is [down by] a factor of 10 or more from its peak in 2006.”
Does this mean Lusi is quieting down for good, or just taking a break before ramping up again? Nobody knows for sure. It “made me realize we need to constantly re-evaluate the longevity estimates,” Davies says.
Getting a good estimate of Lusi’s life span is one reason why Humanitus, an education and community development organization based in Australia, organized the conference. After watching a documentary about the mud volcano, Humanitus Executive Director Jeffrey Richards says, he realized that “no one seemed to be looking at the future.” The controversy over the eruption’s cause was overshadowing the disaster, he says. “It has made it difficult for the government to get any sort of international assistance, which is normally the case for any disaster on that scale.”
Ironically, Lusi may offer ways to fix the area’s damaged economy. Businesses could use the heap of mud to make bricks and other construction materials, Richards says, and the mud volcano could even become a tourist destination. After years of coping with the hardships created by the disaster, the people of Sidoarjo “need some good positives to start coming out of this,” Richards says. As he and other scientists at the conference suggest, “It’s time to look at Lusi as a positive for this region.”