Earthquakes can involve shifting hundreds of kilometers of rock by several meters, changing the distribution of mass on the planet. This affects the Earth’s rotation, said Richard Gross, a geophysicist at NASA’s Jet Propulsion Laboratory in Pasadena, California, who uses a computer model to calculate the effects.
“The length of the day should have gotten shorter by 1.26 microseconds (millionths of a second) [as the result of the recent Chilean earthquake],” Gross, said today in an e-mailed reply to questions. “The axis about which the Earth’s mass is balanced should have moved by 2.7 milliarcseconds (about 8 centimeters or 3 inches).”
(H/T Spiiderweb™)
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