The Telegraph
Since 1st March, 1999
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Earth ringing like a hard-hit bell

Jan. 9: When the earth is 'ringing like a bell', shouldn't its inhabitants be swinging'

Not quite. Australian scientists said the movement is imperceptible to all but the most sensitive equipment.

Much of the earth is still 'ringing like a bell' two weeks after the December 26 earthquake that triggered tsunamis around the Indian Ocean killing over 150,000 people, the scientists said.

It is more like vibration than ringing, really, and it may continue for weeks.

Australian National University scientists said hyper-sensitive gravity-measuring equipment had picked up the reverberations, a rare seismic event.

'These are not things that are going to throw you off your chair, but they are things that the kinds of instruments that are in place around the world can now routinely measure,' said Herb McQueen, of the university's earth sciences research school.

'It is certainly above the background level of vibrations that the earth is normally accustomed to experiencing.'

'Ringing like a bell' that had been forcefully struck is the language he used to describe the phenomenon, recorded at the Mount Stromlo observatory in Canberra in the aftermath of the magnitude 9 earthquake the day after Christmas.

'(It) corresponds to about a millimetre of vertical motion of the earth,' he said. 'The early signals were much stronger.'

Immediately after the quake, the oscillation was probably in the 20 to 30 cm motion range that is typically generated in the earth by the movements of the sun and moon.

'This particular earthquake, because it was 10 times larger than most of the recent large earthquakes, is continuing to reverberate,' McQueen said.

'We can still see a steady signal of the earth vibrating as a result of that earthquake two weeks later. From what it looks like, it appears it will probably continue to oscillate for several more weeks.'

Just after the quake, US scientists said it might have permanently accelerated the earth's rotation ' shortening days by a fraction of a second ' and caused the planet to wobble on its axis.

They also said it had permanently altered the map of Asia by moving some small islands up to 20 metres. There is a dispute among scientists whether there have been shifts or tilts, including in the Andaman and Nicobar Islands.

Scientists may say the swing cannot be felt, but the ground beneath our feet has not stopped shaking since December 26.

This evening, there was an earthquake measuring 4.4 on the Richter scale in Japan. The Andamans have not had a respite from tremors for the past two weeks.

Nature-caused misery today also visited Europe, which lost hundreds of vacationers to the tsunami. Powerful winds and heavy rain swept across northern Europe overnight from Britain to Russia, leaving at least 13 dead, inundating areas of Britain and suspending key air and sea transport.

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