Thursday, March 11, 2010
The World is stretcing, as the infinite light, comes into an finite world.
Chilean Quake May Have Shortened Earth Days
3-1-10
The Feb. 27 magnitude 8.8 earthquake in Chile may have shortened the length of each Earth day.
JPL research scientist Richard Gross, computed how Earth's rotation should have changed, as a result of the Feb. 27 quake.
Using a complex model, he and fellow scientists came up with a preliminary calculation: that the quake should have shortened the length of an Earth day, by about 1.26 microseconds. (a microsecond, is one millionth of a second).
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Mr. Gross claimed, the calculated changes in the length of a day, are permanent.
An earthquake can make Earth rotate faster, by nudging some of its mass closer to the planet's axis, just as ice skaters can speed up their spins, by pulling in their arms.
Conversely, a quake can slow the rotation, and lengthen the day, if it redistributes mass away from that axis.
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Perhaps more impressive, is how much the quake shifted Earth's axis. Gross calculates, the quake should have moved Earth's figure axis (the axis, about which Earth's mass is balanced), by 2.7 milliarcseconds (about 8 centimeters, or 3 inches).
Earth’s figure axis, is not the same, as its north-south axis; they are offset by about 10 meters (about 33 feet).
Islands could have shifted or raised in the ocean; such as Santa Maria Island near Concepcion.
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By comparison, Gross said, the same model estimated the 2004 magnitude 9.1 Sumatran earthquake, should have shortened the length of day by 6.8 microseconds, and shifted Earth's axis by 2.32 milliarcseconds (about 7 centimeters, or 2.76 inches).
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.