As steaming mud continues to pour over Sidoarjo, in eastern Java, Indonesia, geologists who have visited the scene say the four-month-old eruption may neverbe stopped — at least not by human intervention.
Before (above) and after (below). You can see the source of the mud in the centre, and the attempts to wall it in. For more satellite pictures, see here.
Images acquired and processed by CRISP, National University of Singapore IKONOS image © CRISP 2004
The best way of dealing with the mud may be to pump it out to sea, as Indonesia’s government is planning. But a long-term solution could involve putting the mud to commercial use in a health resort or as construction material.
These ideas won’t immediately console the 11,000 people who have lost their homes since 28 May, when hot mud and gas first gushed from a hole near a drilling well, in what is probably a mud volcano (see ‘Mud volcano floods Java‘). According to recent reports, four villages and 20 factories have been submerged, and the mud is now flowing at over 125,000 cubic metres a day. No deaths have been reported.
The company that drilled the well, PT Lapindo Brantas, has agreed to bear the costs of clean-up, resettlement and damage limitation, which have been estimated at over US$160 million by government officials.
Adriano Mazzini, a geologist from the University of Oslo, Norway, has been to look at the eruption, nicknamed ‘Lusi’ (for ‘lumpur Sidoarjo’: lumpur means ‘mud’ in Indonesian). “It’s difficult to predict when it is going to stop,” he says. Attempts to plug the flow have so far failed.
At the moment the mud is contained by a hastily built belt of dams in the area, says Mazzini. These have been breached several times, however, and are causing further problems of their own: because the dams force the mud to pile up, the extra weight is pushing the land down faster into the underground voids left by the erupted mud.
The rainy season usually hits Java in October. With that additional source of flooding looming, a concerned government has authorized pumping out some of the mud into the nearby Porong river and out to sea. This had earlier been rejected on environmental grounds: it is not clear yet if the mud is dangerously toxic. Still, mud volcanoes often erupt into the sea naturally, points out Richard Davies, a geologist at Durham University, UK.
These measures can only be a temporary solution, says Mazzini. “You can continue for ever building dams, filtering and flushing out mud. Suppose in another year it hasn’t stopped — it will all deposit in the river and have to be drained.” Instead, he advocates, the mud should be put to good use.
Mud and earth could be used to make bricks for the construction industry, for example. The government could consider tapping the boiling mud and gas for a source of geothermal energy. Should the mud prove not to be toxic, and the reported hydrogen sulphide gas dissipates, the area might become a health spa, with people bathing in mud craters.
And for geologists, the mud flow presents a great scientific opportunity. “Studies on a mud-volcano structure that’s been born out of the blue have never been done. There’s all the data from the company doing the drilling. It’s like a laboratory out there,” Mazzini says.
It is still not clear whether the mud flow can be called a conventional mud volcano, by which geologists mean the uprush of trapped mud and gas from a spot where one tectonic plate is sliding beneath another.
It’s possible that watery mud was instead trapped within old deposits of coral underground, and these have fractured. Or, as Mazzini explains, magmatic volcanoes a few kilometres to the south-west may be leaking hot fluids that are migrating underground, in a hydrothermal system like the geysers in the United States’ Yellowstone National Park. Alternatively, magma itself may be migrating horizontally into sediments underground, heating gas and water elsewhere at depth.
Nor is it known what caused the eruption: whether Lapindo’s drilling, an earlier minor earthquake or a combination of the two. “You needed to have a video camera there,” says Mazzini.