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article imageJapan earthquake shortened day on Earth, tilted axis by 25cm

By Andrew Moran     Mar 15, 2011 in Science
Tokyo - Scientists have learned that last week's devastating 9.0-magnitude earthquake, which caused nearly $200 billion in damage in Japan, actually shortened the Earth's day by a fraction and it shifted the planet's axis by 25 centimetres.
As most of the world assesses the amount of deaths, injuries and damage in Japan, researchers are releasing the scientific outcomes of the overwhelming dozens of earthquakes and tsunami in Japan.
It has already been reported that a Japanese island shifted eight feet, but the earthquake had more of a worldwide impact. The Earth’s 24-hour day was shortened by 1.8 microseconds, according to NASA’s Jet Propulsion Laboratory, reports Voice of America. The temblor shifted how Earth’s mass is distributed.
It was originally estimated to be 1.6 microseconds but NASA’s geophysicist Richard Gross revised the time to 1.8 microseconds – a microsecond is one millionth of a second.
“By changing the distribution of the Earth's mass, the Japanese earthquake should have caused the Earth to rotate a bit faster, shortening the length of the day by about 1.8 microseconds,” said Gross in an interview with
But this isn’t the first time that a major earthquake has shortened a day. Last year’s 8.8-magnitude earthquake in Chile shortened the day by 1.26 microseconds. In 2004, the 9.1-magnitude earthquake in Indonesia forced us to lose as much as 6.8 microseconds.
Last week’s natural disaster didn’t just cost us a microsecond, but it also was able to shift the planet’s axis by 6 ½ inches, or 17 centimeters – although other estimates suggest approximately 10 inches (25 centimeters), reports the Metro UK.
“This shift in the position of the figure axis will cause the Earth to wobble a bit differently as it rotates, but will not cause a shift of the Earth's axis in space – only external forces like the gravitational attraction of the sun, moon, and planets can do that,” said Gross.
U.S. Air Force search and rescue personnel witness a house adrift off the coast of northeastern Japa...
U.S. Air Force search and rescue personnel witness a house adrift off the coast of northeastern Japan
U.S. Air Force photo by Airman 1st Class Katrina R. Menchaca
Don’t get too concerned about it, though, because some scientists say we won’t see any of these effects for many centuries. “Ten inches [25cm] sounds like quite a lot when you hold a ruler in front of you. But if you think of it in terms of the earth as a whole, it's absolutely tiny; it's minute,” stated University of Toronto Professor Andrew Miall, reports the Daily Mail.
“It's going to make minute changes to the length of a day. It could make very, very tiny changes to the tilt of the earth, which affects the seasons, but these effects are so small, it'd take very precise satellite navigation to pick it up.”
The death toll in Japan has 3,373 and about 6,746 are still missing, notes Xinhua.
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