LONDON - The underwater quake, which the US Geological Survey put
at magnitude 9.0, was the biggest since 1964, when a 9.2-magnitude
temblor struck Alaska, also touching off tsunami waves. There were
at least a half-dozen powerful aftershocks, one of magnitude
7.3.
Mr Enzo Boschi, the head of Italy's National Geophysics Institute,
likened the quake's power to detonating a million atomic bombs the
size of those dropped on Japan during World War II, and said the
shaking was so powerful it even disturbed the Earth's
rotation.
'All the planet is vibrating' from the quake, he told Italian state
radio. Other scientists said it was too early to say whether the
rotation was affected by the quake.
The earthquake occurred at a spot where the Indian Ocean plate is
gradually being forced underneath Sumatra, which is part of the
Eurasian plate, at about the speed at which a human fingernail
grows, Mr David Booth, a seismologist at the British Geological
Survey explained.
'This slipping doesn't occur smoothly,' he said. Rocks along the
edge stick against one another and pent-up energy builds over
hundreds of years.
It's 'almost like stretching an elastic band, and then when the
strength of the rock isn't sufficient to withstand the stress, then
all along the fault line the rocks will move,' he said.
Indonesia is well-known as a major quake centre, sitting along a
series of fault lines dubbed the Ring of Fire. But scientists are
unable to predict where and when quakes will strike with any
precision.
The force of Sunday's earthquake shook unusually far afield,
causing buildings to sway hundreds of kilometres from the
epicentre, from Singapore to the city of Chiang Mai in northern
Thailand, and in Bangladesh. -- AP
