According to scientists at NASA, the massive Chile earthquake that struck at a magnitude of 8.8 on February 27 might have shifted the earth's axis by 8cm shortening the day by 1.26 microseconds (a microsecond is a millionth of a second).
The Sumatran (in Indonesia) earthquake in 2004 at a magnitude of 9.1 shortened the day by 6.8 microseconds!...Yeah the earthquake that caused the massive Asian tsunami.
So how does this happen then Jim?
Super earthquakes like these can shift huge amounts of rock and alter the distribution of mass on earth affecting the rate at which the earth rotates. If the rate of rotation is affected, the length of the day is also affected.
