Science

Chilean earthquake may have shortened earth day by microsecond: NASA

10:26 PM that's me 0 Comments

***sorry if I din't tranlated right***
The powerful 8.8 magnitude earthquake that rocked chile could have tilted the axis of the earth and therefore the days are shorter.

That's Richard Gross conclusion, a researcher at the jet propulsion laboratory of the u.s. space agency NASA.

The scientist used a complex model which won a preliminary calculation shows that the quake could have shortened 1.26 microseconds ( a microsecond equals one millionth of a second) the length of each day on Earth.

What surprised most to Dr. Gross, however, is how the earthquake might have titled the axis of the Earth.

According to the investigator the quake would have tilted the earth's axis at 2.7 milli-arcseconds (about 8 centimeters).

The same model estimated the magnitude of Sumatra-Andaman earthquake of 9.1 in 2004 this could have shortened the length of the days of 6.8 microseconds and tilted Earth's axis in 2.32 milliseconds of arc (about 7 centimeters).



The scientist said that while the Chilean earthquake was smaller than the Sumatra, Chile would have a little more inclined earth's axis for two reasons.

"Firs, unlike the Sumatran earhquake was located near Ecuador, Chile earthquake was located in the middle latitudes of the Earth, allowing it to more effectively change the figures in the axis", says Dr. Gross.
"Secondly, he added, the fault responsible for the 2010 earhquake in Chile descends beneath the surface of the Earth at an angle slightly steeper than the fault responsible for the earthquake of 2004."

"This makes the failure of Chile more effective to move the mass of the earth vertically and therefore more effective to chang the figures of Earth's axis, "he explains.


" As a ballet dancer"

As explained to BBC Science Gangui Dr.Alexander, a researcher at the Institute of Astronomy and Apace Physics at the University of Buenos Aires, Argentina, it is expected that a movement so strong in the earth's crust causes such as changes in the way moves the planet's mass.
"We know the Earth is not a completely rigid body but subject to many distubances according to seasonal effects," explains the scientist.

"So a plate movement as it was at the origin of both the earthquake of 2004 as the 2010 course will change the distribution of mass in the planet."


The shift isn’t about to cause a Roland Emmerich like end of days scenario or affect the seasons or weather, but it will shorten every day by 1.26 microseconds
"The efect is the same when a ballet dancer turns on one foot with open arms and their rotational movement is slow and when she close her arms the movement is faster."
Now with the Earth, says the scientist, something similar happened, since the movement became more rapid shift by the change in the distribution of matter in the equatorial zone.
As explained by Dr.Ganqui, although these changes in the position of the Earth are important is unlikely to detect.

"The truth is that any of these movements of large amounts of mass of plate tectonics cause a small disturbance in the dynamics of the Earth as a cosmic body.
"But it is notoriously difficult that we can detect it in our every day life,"he adds.


How does an earthquake move the planet’s axis? A sizable quake can shift huge amounts of rock, changing the distribution of mass on the planet. That change alters the rate at which the planet rotates, and rotation determines a day’s length. Scientists explained that the key to the shift was the location of the quake, and the fact that the fault sliced through Earth at a steeper angle, making “the Chile fault more effective in moving Earth’s mass vertically and hence more effective in shifting Earth’s figure axis.”(sources: bbc & unhabit)

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