Quake caused a ripple effect on our planet

Washington - The underwater earthquake that triggered the devastating tidal waves in south-east Asia permanently sped up Earth's rotation, shortening the days by about three microseconds, a scientist with the United States space agency said on Wednesday.

Geophysicist Richard Gross, from the National Aeronautics and Space Administration, said in a telephone interview from Pasadena, California, that the time difference was probably too small to measure.

The time change occurred when Sunday's magnitude-9 earthquake pitched Earth's axis by 2.5cm, according to Gross' calculations.

He said Earth became more compact and began moving faster when the two tectonic plates that triggered the earthquake were pushed over one another.

The resulting movement of Earth's axis, however, was not large because the temblor occurred near the equator, Gross added.