Chilean quake may have moved Earth's axis

March 2, 2010 at 9:38 AM
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PASADENA, Calif., March 2 (UPI) -- NASA scientists say February's magnitude 8.8 Chilean earthquake might have shifted one of the Earth's axes and shortened the length of an Earth day.

Researchers at the space agency's Jet Propulsion Laboratory in Pasadena, Calif., say their preliminary calculations suggest the Feb. 27 earthquake shortened the length of a day by about 1.26 microseconds -- a microsecond is one-millionth of a second -- and moved Earth's figure axis -- about which the planet's mass is balanced -- by about 3 inches. The scientists noted Earth's figure axis is not the same as its north-south axis, with the two being offset by about 33 feet.

JPL scientist Richard Gross said the same computer model was used to estimate the 2004 magnitude 9.1 Sumatran earthquake and it showed last week's event, although of a lesser magnitude, had a bigger impact on the planet because it was located in Earth's mid-latitudes -- not near the equator. Also, the fault that caused the Chilean quake dips into the planet at a steeper angle, making it more effective in moving Earth's mass vertically and shifting Earth's figure axis.

Gross said his calculations will likely change as data on the quake are further refined.

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