We’ve seen it so many times on TV: the arrogant scientist or evil corporation meddles with Forces We Cannot Understand (TM) and Mother Nature lashes back with earthquakes, tsunamis, or volcanic eruptions. This time, it looks like it may actually be true, at least minus the pejorative adjectives. But the results are a lot less photogenic than Hollywood would like–450 hectares of mud.

What used to be a rice paddy in Indonesia is now the site of a mud volcano that has been bubbling along for nine months. The village of Sidoarjo has been flooded with mud, burying houses and rendering 24,000 people homeless. So far fifteen disaster workers have been killed while trying to divert the mud away from homes and into a nearby river. The flow has only increased since the mud volcano started erupting, and there’s no telling when it might stop.

The cause of the mud volcano is unclear. An article in Nature now lays out the two possible causes. The first is nearby exploratory drilling by the oil company Lapindo:

The first published analysis of the mud volcano, from a group led by Davies (R. J. Davies et al. GSA Today 17, 4–9; 2007), conjectures that the water driving the mud volcano comes from that Kujung limestone, and suggests that the escape could have been caused by Lapindo’s drilling at a site called Banjar Panji-1. The Banjar Panji-1 well is an exploratory well, started when little was known about the underlying geology. In his paper, Davies argues that the drill at Banjar Panji-1 punctured the Kujung, allowing high-pressure water and gas to escape into the borehole. The fluids forced their way into the surrounding rock and fractured it and the high-pressure water passing through these fractures liquefied the surrounding shale before new cracks gave it access to the surface. The cracks have been growing ever since.

The second possibility is that the mud volcano was caused by an earthquake:

Istadi offers another explanation for the volcano’s origin. The day before the volcano erupted, a magnitude-6.3 earthquake struck Yogyakarta, 280 kilometres to the southwest of Sidoarjo. Istadi says that seven hours after the earthquake, drilling fluid, which is circulated up and down the borehole to keep the pressure higher than that of the fluids in the surrounding rock, leaked out. He thinks this drilling loss, or ‘loss of circulation’, as it is known, was caused by shock waves from the earthquake — and that the same shocks might have triggered the mud volcano: “Faults became open, lost their sealing capacity, and became permeable.” Those faults, he says, “served as the conduit where the mud flows out”. This explanation squares well with the views of one of the country’s most powerful and richest men, Aburizal Bakrie, the Coordinating Minister for People’s Welfare. Bakrie, whose family owns part of Lapindo, has long been arguing that Lusi is just another “natural disaster” — no more the fault of an individual company than the earthquake itself, or the floods that have hit Jakarta in the past months.

However, Nature reports that other recent earthquakes of similar strength failed to trigger this mud volcano, and according to one geophysicist this volcano was not close enough nor strong enough to do the job.

While I (and, I think, Nature) lean towards thinking this mud volcano was the result of drilling, it could be years before we know the truth–was it Mother Nature’s caprice, or her vengeance?

Cyranoski, D. “Indonesian eruption: Muddy waters.” Nature. 2007, 445, 812-815.