Thursday, March 17, 2011
Earthquake in Japan would have shortened the length of day in the world
The earthquake of 8.9 magnitude on the Richter scale that struck Japan on March 11, could have changed the Earth's axis and shortened the days, as detected by NASA scientists.
His calculations indicate that changing the distribution of the mass of Earth, the earthquake must have caused it to spin a little faster, shortening the length of a day about 1.8 microseconds (a microsecond is one millionth of a second).
The investigator's Jet Propulsion Laboratory (JPL) of NASA, Richard Gross and his team have implemented a complex geological model for a preliminary theoretical calculation of how the earthquake in Japan, the fifth largest since 1900, has affected Earth's rotation.
The calculations also indicate that the movement should have changed the position of the axis (around which the planet's mass balance) about 17 centimeters in the direction 133 degrees east longitude.
This should not be confused with the north-south, also has moved about 10 meters, and the Earth will wobble as it spins differently, but it will not cause a significant change.
NASA said in a statement that both estimates are likely to change as the earthquake data are more precise.
NOT THE FIRST TIME
Gross estimated the magnitude 8.8 earthquake that occurred in Chile last year should have shortened the length of the day at about 1.26 microseconds and shifted the axis of the Earth in about 8 inches.
A similar calculation was made after 9.1-magnitude earthquake that struck Sumatra in 2004, indicating that natural phenomena should have shortened the length of day 6.8 microseconds and shifted the axis of the earth about 7 inches.
Gross explained, in theory, any phenomenon that redistributes the mass of the Earth will change the planet's rotation.
"The rotation of the Earth changes all the time, not only as a result of earthquakes, but also major effects such as changes in atmospheric winds and ocean currents," he said.
"In the course of a year, day length increases and decreases by about one thousandth of a second, which is a change approximately 550 times greater than the change caused by the earthquake in Japan."
In this regard, he indicated that changes in the rotation of the Earth by earthquakes should have no impact on everyday life.