NASA: Chile earthquake shifted Earth's axis; shortened day
The Feb. 27 earthquake that killed more than 700 people in Chile probably shifted the Earth's axis and shortened the day, a NASA scientist said.
Because earthquakes involve the movement of hundreds of kilometers of rock, they can actually change the distribution of mass on the planet, affecting the Earth's rotation, said NASA geophysicist Richard Gross in a Bloomberg report.
“The length of the day should have gotten shorter by 1.26 microseconds (millionths of a second),” 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).”
While most changes are too small to physically detect, some are more obvious: islands could have shifted or raised in the ocean, such as Santa Maria Island near Concepcion, according to the report.
Here's a harrowing look at the earthquake, which shook for some 90 seconds:
The Chile earthquake registered 8.8 magnitude on the Richter scale. In comparison, the 2004 Sumatran quake of magnitude 9.1 shortened the day by 6.8 microseconds and shifted the axis by about 2.3 milliarcseconds, Gross said.
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