Indonesian mud geyser linked to earthquake

Nature : A recent study published in Nature Geoscience links the mud disaster that began in Indonesia in 2006 with natural, rather than manmade, causes. On 29 May 2006, a mud geyser suddenly began to erupt near Sidoarjo in East Java—and has continued intermittently ever since. To date, some 40 000 residents have lost their homes. Drilling at a nearby gas exploration well had been blamed for setting off the eruption. In their study, Stephen Miller of the University of Bonn in Germany and colleagues propose instead that the mud flow originated from an unusual geologic formation beneath the ground. Seismic imaging data indicate that a layer of dense parabolic-shaped rock is sitting on top of a reservoir of mud. Seismic waves from a shallow magnitude-6.3 earthquake that struck 250 km away 47 hours before the mud eruption began may have been reflected and focused by the satellite-dish-like rock and liquefied the mud. The mud then found its way into an adjacent fault, which led to a hydrothermal volcanic system deeper down. It is likely that pressure had been growing for several decades and the 2006 quake triggered the unfortunate chain reaction.