Pupils jump to it in quake experiment

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The Independent Online

If you feel the Earth move at 11am today, don't worry – it's probably just the children.

If you feel the Earth move at 11am today, don't worry – it's probably just the children. To initiate Science Year, one million of them will jump off chairs at more than 3,000 schools across Britain in an experiment to investigate whether humans can make their own earthquakes.

According to Steven Chapman of the British Association, if one million children weighing an average of 50kg (7st 12lb) jump from a height of 20cm (8in) they will release 100 million joules. If they do this 20 times in the allotted minute for the experiment, they will release two billion joules, the same amount of energy as is released in an earthquake measuring 3 on the Richter scale.

"Certainly it would be feasible for seismologists to measure it," Dr Chapman said. "There are typically 100,000 earthquakes of this magnitude in the world every year. Though their effects cannot be felt, they can be measured."

Dr Ted Nield of the British Geological Society said Britain had hundreds of magnitude 3 earthquakes every year, "but they don't do anything". Teams at the society will be able to monitor their seismographs to see whether the experiment succeeds or whether there were too many truants.

A long-standing hypothesis suggests that if everyone in China were to jump off a chair at the same time, the movement of the Earth would cause a giant wave, or tsunami, that would engulf the west coast of America.

For obvious reasons that remains untested. But earthquakes generated by humans alone are more common than one might expect, and are generally associated with rock concerts. When the pop group Madness played at Finsbury Park, north London, in August 1992, the co-ordinated jumping of fans caused a mini- earthquake that was equivalent to magnitude 4.5 – enough to cause nearby tower blocks to sway.

Dr Chapman said the inspiration for today's experiment was not from that incident. "It was one of our workers, actually, who said that they tried the same sort of thing in Australia."

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