Japan’s 8.9 Mega Earthquake Shortened the Earth’s Day

Sunday, March 13, 2011

Geophysicist Richard Gross at NASA’s Jet Propulsion Laboratory in Pasadena, CA says the 8.9 earthquake that struck Japan on Friday shortened the length Earth’s day by a fraction and shifted how the planet’s mass is distributed.

A new analysis of the 8.9-magnitude earthquake in Japan has found the mega tremblor accelerated the Earth’s spin, and shortened the length of the 24-hour day by 1.8 microseconds.

This isn’t the first time a massive earthquake has changed the length of Earth’s day. Major temblors have shortened day length in the past.

The 8.8-magnitude earthquake in Chile last year also sped up the planet’s rotation and shortened the day by 1.26 microseconds. The 9.1 Sumatra earthquake in 2004 shortened the day by 6.8 microseconds.

And the impact from Japan’s 8.9-magnitude temblor may not be completely over.The weaker aftershocks may contribute tiny changes to day length as well.


This entry was posted in Earthquakes, News, Science and tagged , , . Bookmark the permalink.

10 Responses to Japan’s 8.9 Mega Earthquake Shortened the Earth’s Day

  1. Estacada says:

    It’s so interesting to think everything we assume to be fixed, like the orbit of the earth, the moon and the sun, can be changed and altered depending on the given event.

    I remember decades back in the 1960’s, when the US landed on the moon, some moron immediately proposed we detonate nuclear bombs on the surface just for the fun of it. Of course, if we had done it, there was a real risk that the moon would be sent off its orbit and the oceans on earth would rise up and spill over the continents.

  2. Joe in Colorado says:

    Very intriguing stuff. BTW, the new blog digs look great. Very professional.

  3. jim says:

    so if our days keep getting shorter and shorter does that mean it will be tomorrow before ya know it?

  4. R.J. says:

    Did you see where the earthquake was upgraded to a 9.0 last night?

  5. Arizona Leatherneck says:


    The power of nature unleashed on the planet. It’s humbling.

  6. Thai Noodles says:

    Shweet Jebus!

  7. Octopus says:

    accelerated Earth’s spin, shortening the length of the 24-hour day by 1.8 microseconds …

    Does this mean we get overtime pay for cramming everything into a shorter day?

  8. Adirondacky says:

    The great Madras earthquake in Missouri in the 1800’s made the Mississippi River run backward and it was felt in Boston. This is extraordinary.

  9. Jolly Roger says:

    And those nuke plants may shorten the days of a hell of a lot of people. Sea water for cooling is a “that’s all she wrote” move. It’s bad.

  10. Crazy the earth is really such a unstable place. Disasters can still have such great effects even with the advance of human technology still no match for nature

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