Chile’s Megathrust Earthquake Changed The World

March 15th, 2010 - 7:28 pm ICT by GD  

By Madhuri Dey
chile3Mar 15, (THAINDIAN NEWS) According to a professor of geology and geophysics with the University of Minnesota, Justin Revenaugh, the effects of the phenomenal earthquake in Chile on the geography and the movements of the earth were very predictable, one looked at the kind of earthquake that the country suffered. As the Geological Survey of the United States had reported earlier, the earthquake in Chile had been of the mega thrust kind, one that caused the maximum damage. In this process, one tectonic plate shifts under the other, instead of riding up on it, or moving apart, which leads to faults in the earth’s surface.

This process is called subduction. So far, there has been only 14 such cases recorded. These are generally very high in magnitude, and measure 7.5 and above. Due to their intensity, and the huge amount of energy that is released by the subduction of the two plates, the shape of the earth is somewhat affected, leading to what happened this time in the Chile earthquake. The change in shape led to a slight shift in the axis, causing a geographically minimal shortening of the day.

The speed of rotation of the earth increased due to the shift in the axis. This can be explained by the fact that the mega thrust earthquake caused the earth to get more compact in form, leading to a faster spin. This, in turn, has led to the shortening of the length of the day by about 1.26 millionth of a second. However, the Chile earthquake, though not predicted to the minute, could be expected, as some of the mega thrust quakes had taken place in the country before, and it is known to be seismically very active.

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