Salt of the earthquake

STEVE CONNOR

Science Correspondent

The chemical composition of mineral water could hold the secret to predicting earthquakes.

Scientists studying the Kobe earthquake that struck Japan last January have found that bottled mineral water became more salty just before the disaster. The water, also used for making sake, was bottled from wells in the area over the 18 months prior to the earthquake. However, its salty chloride and sulphate content only began to rise six months before the earthquake.

Following the disaster, scientists Urumu Tsunogai and Hiroshi Wakita, from the University of Tokyo, bought bottles of mineral water ''with as many different bottling dates as possible'', they say in the journal Science.

They analysed the chloride and sulphate salts in each bottle of water and found the rise immediately before the earthquake was significant and could not be explained by any factor other than geological changes.

Chi-Yu King, a geologist at the US Geological Survey, in California, said that analysing bottled mineral water for the signs of an earthquake was ''very ingenious'' and cheap.