The8.8 magnitude earthquakeon the richter scale that shookChile in 2010 slightly reduced the length of the day and shifted the Earth’s axis by eight centimeters. That is the conclusion reached by Richard Gross, a researcher at NASA’s Jet Propulsion Laboratory, who in a preliminary calculation has estimated that the earthquake may haveshortened 1.26 microseconds the length of each day on Earth.
The same model used by Gross for his calculations was used to estimate that the Sumatra-Andaman earthquake of magnitude 9.1, which took place in 2004, may have shortened the length of days by 6.8 microseconds and tilted the Earth’s axis by 2.32 milliseconds of arc (about 7 centimeters). The scientist explains that, although the earthquake in Chile was smaller than the one in Sumatra, the one in Chile managed to tilt the earth’s axis a little more because it was located in theEarth’s middle latitudes, with which it was able to change the axis figures more effectively than the earthquake in Sumatra, near the equator. Furthermore, according to Gross, “the fault responsible for the 2010 earthquake in Chile descends below the Earth’s surface at a slightly steeper angle than that of the fault responsible for the 2004 earthquake.”
The Earth is not a completely rigid body, it is subject to many disturbances, andthe movements of large amounts of plate tectonic massthey can cause changes in its dynamics. However, experts remember that these changes will not be noticed in our daily lives.
One thousand megatons
According to calculations by the British Geological Survey (BGS), the enormous amount of stress stored for hundreds of years at the edge of the tectonic plates where the Chile earthquake occurred – and where there had been no strong shaking since 1935 released energy equivalent to more than thousand megatons of TNT in a few tens of seconds. The wave caused by the earthquake off the coast of Chile took 10 hours to cross the Pacific Ocean.
