• Question: I heard that the earthquake that hit Japan in 2011 shortened the day ever so slightly. Is this true?

    Asked by shanman to Angela, Gabriele, Karen, Maria, Shane on 14 Nov 2013.
    • Photo: Shane Mc Guinness

      Shane Mc Guinness answered on 14 Nov 2013:

      You’re exactly right Shanman!
      Because of the 8.9 magnitude earthquate that caused the tsunami near Japan, the earth’s spin has slightly sped up, because of the shifting weight of movement of crust.
      This means that our days are now 1.8 microseconds shorter! You’d never notice it though as it will take over a million years for the day to become 2 seconds shorter. By that time something else could happen to reverse it! So you haven’t really lost any time at all!

    • Photo: Angela Stevenson

      Angela Stevenson answered on 14 Nov 2013:

      Yes! at a magnitude of 9.0, the 2011 earthquack that hit Japan was considered to be one of the biggest (5th largest!) to have been recorded. It was so strong that it may have shortened the length of each Earth day and shifted its axis. NASA applied a complex model to calculate how this earthquake managed to affect the Earth’s rotation. By changing the distribution of Earth’s mass, the Japanese earthquake caused Earth to rotate a bit faster, shortening the length of the day by about 1.8 microseconds (a microsecond is one millionth of a second). Excellent question Shanman!

    • Photo: Karen McCarthy

      Karen McCarthy answered on 14 Nov 2013:

      I never knew this fact but it has totally blown my mind! Nice one Shanman, and Shane too!