Earthquake Rocks the World Off Axis


The recent earthquake in Chile was so big, it altered the earths rotation.  So if you notice the days getting shorter, blame the quake.  According to NASA scientist Richard Gross, the earth has been knocked about 3 inches off of its axis!  This resulted in a 1.26 microsecond shortening of the day. 

Actually, this isn’t so unusual.  Any time a major geological event moves the mass of the earth around a bit, it will alter the way the earth spins.  The last time we saw a big jolt was in 2004’s Sumatra quake of 9.1 altered the axis of the planet by 2.76 inches.  We lost over 6 microseconds on that one. 

When are we going to get a quake that lengthens the day?  That’s what I want to know.

Gross said that even though the Chilean earthquake is much smaller than the Sumatran quake, it is predicted to have changed the position of the figure axis by a bit more for two reasons. First, unlike the 2004 Sumatran earthquake, which was located near the equator, the 2010 Chilean earthquake was located in Earth’s mid-latitudes, which makes it more effective in shifting Earth’s figure axis. Second, the fault responsible for the 2010 Chiliean earthquake dips into Earth at a slightly steeper angle than does the fault responsible for the 2004 Sumatran earthquake. This makes the Chile fault more effective in moving Earth’s mass vertically and hence more effective in shifting Earth’s figure axis.

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