INDONESIA should steel itself for a far nastier rumble than the earthquake it suffered last week.
鈥淎nother earthquake is on its way, and all it will take to trigger it is the pressure of a handshake,鈥� says John McCloskey of the University of Ulster in Coleraine, Northern Ireland.
The city of Padang on the Indonesian island of Sumatra experienced a magnitude-7.6 earthquake on 30 September. At first, geologists assumed this was the earthquake they had been predicting for many years along the tectonic boundary between the Indian, Australian and Eurasian plates (see Map). This interface slipped in 2004 and 2005, but one region has not experienced the stress relief of an earthquake for over 200 years, according to a recent analysis of the region by McCloskey. He drew on research into historical growth rings in coral, which show no sign of sea-floor uplift (Nature, ). 鈥淎 shallow earthquake鈥� is long, long overdue,鈥� says McCloskey.
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Yet the Padang earthquake originated far from the boundary and deeper than the interface between the plates. It may have been due to a vestigial weakness left behind by an ancient plate boundary, he suggests.
McCloskey鈥檚 computer simulations suggest that when the boundary does slip, it will trigger a tsunami that could be as high as 10 metres.
鈥淲hen the boundary does slip, it will trigger a tsunami that could be as high as 10 metres鈥�