Japan’s earthquake, which was the precursor to the devastating tsunami that swept the country, was also responsible for another less significant phenomenon- speeding up Earth’s rotation.
According to NASA geophysicist Richard Gross’ calculations, Earth’s rotation sped up by 1.6 microseconds which in turn shortened the day on Friday.
"The length of the day should have gotten shorter by 1.26 microseconds [millionths of a second]," Richard Gross, a geophysicist at NASA's Jet Propulsion Laboratory, told Bloomberg. "The axis about which the Earth's mass is balanced should have moved by 2.7 milliarcseconds [about 8 centimeters or 3 inches]."
The shift in Earth’s mass caused by the 8.9-magnitude earthquake was the main reason behind this. Sudden changes in the dimensions of the Earth's tectonic plates can alter Earth's velocity, which can either speed up or slow down the rotation.
The effect on the speed and the change in the length of the say was so slight, that it went unnoticed.
That change in rotation speed is slightly more than the one caused by last year's larger Chile earthquake. But 2004's bigger Sumatra earthquake caused a 6.8-microsecond shortening of the day.
The Japan quake is the fifth strongest since 1900.
(Dailybhaskar)
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(Colombo Lankapuvath)
