When it comes to natural disasters, the Japanese government is good with numbers. It expects, for instance, a magnitude-8.1 quake to strike in the next 30 years with an epicentre in the Nankai trough â?? a depression in the sea-floor 100 kilometres off the country’s east coast. And when it hits, it is likely to kill between 12,000 and 18,000 people.
The Nankai trough lies in a subduction zone, a perilous region in which one tectonic plate dives under another, building up the sort of rock strain that can unleash the world’s most powerful earthquakes. All earthquakes with a magnitude of greater than 9 have occurred in these zones. And although the next earthquake at Nankai is not expected to be quite this big, the region could prove key in understanding why earthquakes in subduction zones release such vast amounts of energy.
Quoted: Harold Tobin of the University of Wisconsin in Madison, the project’s other chief scientist.