Discussion: How Much Did the Earth Move?

[Fraser]

SUMMARY: Last month's catastrophic earthquake and tsunami were powerful enough that they actually changed the Earth's rotation, decreased the length of day, and moved the North Pole. Not much, of course, but enough that scientists can actually measure the effect. Scientists from NASA found that the length of the day shortened by 2.68 microseconds, and the North Pole shifted by 2.5 centimetres (1 inch). The Sumatran earthquake registered as a 9 on the Richter scale, making it the 4th largest earthquake measured in 100 years.

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[antoniseb]

Thanks for posting this. I've heard some crazy things about how much the Earth moved, and this sets it straight.

One of the oddest things I'd heard was that the Earth slowed down it's rotation. Usually when an Earthquake happens, there is some settling, and the Earth compacts [not expands], and so as the ice dancer pulling in her arms on a spin, the Earth speeds up. In this case, the speed-up is about one millisecond/year, which is pretty small compared to the general slow-down from the tides, and so the next leap-second will mostly likely not be delayed by this.

[Tiny]

That's interseting mind if I ask this question, does magnetic field somehow has its own power to slow down the rotation of a planet? And is it true that the Earth moving 05% - 1% Western from space every 24 hours?

[antoniseb]

Originally posted by Tiny@Jan 11 2005, 08:00 PM
does magnetic field somehow has its own power to slow down the rotation of a planet?

Yes, the Earth's magnetic field interacting with its surroundings has a miniscule effect slowing down the Earth's rotation.

is it true that the Earth moving 05% - 1% Western from space every 24 hours?

Sorry, I don't understand this question.