Inside the mysterious mechanics of a mud volcano

In 2006 the ground near Sidoarjo, Indonesia started spitting up mud. The mud volcano, Lusi, has been continuously erupting ever since, displacing 40,000 people and killing fifteen. How long it keeps going depends on the cause, which remains unknown. Some scientists believe Lusi will keep erupting for at least another twenty years. Others believe the volcano may just scratch out an entire century before it stops. What's the truth?

With Lusi closing in on its fifth birthday, scientists are at odds as to how old the mud volcano will get. Already it has splashed 144 million cubic meters of mud over the landscape and destroyed thousands of homes. The eruption started suspiciously close to a mining operation - in May of 2006 the mud started gushing only 200 meters away from workers drilling space for a gas line. Possibly, though, it was a natural occurrence, the result of a nearby earthquake two days before. Since both the earthquake and the drilling have stopped, what keeps driving the mud to the surface of the earth?

Some scientists believe that the mud volcano was started by the mining drill. They think the drill pierced solid rock and excavated a hole to an aquifer below. The water was under pressure, and that pressure pushed it up to the surface, picking up dirt on the way. This could result in a volcano that spits mud for twenty years. And that's the optimistic assessment.

Others think that the pressure doesn't come from below, but from around. There would be a lot of mud just below the surface of the earth. As the mud volcano discharges nearby below-ground matter, it creates a hole into which more mud from surrounding area is drawn. That mud is then pushed up and out into the Indonesian countryside. If that's the case, the volcano has a lot of material to draw. It may give out after forty years, but there's a chance that it could last eighty to ninety years.

That's not a prediction anyone wants to hear. Not only were resettled people hoping to return to their land, but the plants and animals in the area around Lusi are being wiped out. And those whose homes escaped the devastation are now living next to a century-long mudslide. The (sort of) good news is that there is some mud tourism in the area. People are morbidly curious enough to see the devastation that Lusi caused. But those who live in Sidoarjo would happily say goodbye to tourist dollars if the mud would just stop erupting and they could go home.

Via Science.