This view of Earth comes from NASA's Moderate Resolution Imaging Spectroradiometer aboard the Terra satellite.
The Feb. 27 magnitude 8.8 earthquake in Chile may have shortened the length of each Earth day.
JPL research scientist Richard Gross computed how Earth's rotation should have changed as a result of the Feb. 27 quake. Using a complex model, he and fellow scientists came up with a preliminary calculation that the quake should have shortened the length of an Earth day by about 1.26 microseconds (a microsecond is one millionth of a second).
Perhaps more impressive is how much the quake shifted Earth's axis. Gross calculates the quake should have moved Earth's figure axis (the axis about which Earth's mass is balanced) by 2.7 milliarcseconds (about 8 centimeters, or 3 inches). Earth's figure axis is not the same as its north-south axis; they are offset by about 10 meters (about 33 feet).
By comparison, Gross said the same model estimated the 2004 magnitude 9.1 Sumatran earthquake should have shortened the length of day by 6.8 microseconds and shifted Earth's axis by 2.32 milliarcseconds (about 7 centimeters, or 2.76 inches).
Gross said that even though the Chilean earthquake is much smaller than the Sumatran quake, it is predicted to have changed the position of the figure axis by a bit more for two reasons. First, unlike the 2004 Sumatran earthquake, which was located near the equator, the 2010 Chilean earthquake was located in Earth's mid-latitudes, which makes it more effective in shifting Earth's figure axis. Second, the fault responsible for the 2010 Chiliean earthquake dips into Earth at a slightly steeper angle than does the fault responsible for the 2004 Sumatran earthquake. This makes the Chile fault more effective in moving Earth's mass vertically and hence more effective in shifting Earth's figure axis.
Gross said the Chile predictions will likely change as data on the quake are further refined.
http://www.jpl.nasa.gov/news/news.cfm?r ... l&rst=2504
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SCIENTS CLAIM EARTH AXIS SHIFTED 3 INCHES AFTER CHILE QUAKE -DAYS ARE NOW SHORTER
THE earthquake that has killed over 700 Chileans and displaced over two million more has now caused our days to be shorter.
The earthquake that struck Chile measured at an 8.8 magnitude and put the entire Pacific on tsunami alert.
But scientists say the shifting in the tectonic plates has also shifted the Earth's axis.
The Earth’s overall mass distribution has likely been altered which has made the length of a day 1.26 microseconds shorter, NASA scientists say.
"The axis about which the Earth's mass is balanced should have moved by 2.7 milliarcseconds (about 8 centimetres or 3 inche)]," NASA told Bloomberg.
“It’s what we call the ice-skater effect,” David Kerridge, head of Earth hazards and systems at the British Geological Survey in Edinburgh told Bloomberg.
“As the ice skater puts when she’s going around in a circle, and she pulls her arms in, she gets faster and faster. It’s the same idea with the Earth going around if you change the distribution of mass, the rotation rate changes.”
The last time a day was shortened was after the 9.1 magnitude earthquake that sparked the Boxing Day tsunami.
That shift in the tectonic plates that lie underneath the ocean surface caused days to shorten by 6.8 microseconds, scientists say.
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