NASA: Chile quake shortened earth's days, bumped planet off axis

The magnitude 8.8 earthquake that hit Chile over the weekend—killing hundreds, and leaving hundreds of thousands homeless—may have shortened the length of each Earth day, according to JPL research scientist Richard Gross.


He 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).

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).

Chilean Quake May Have Shortened Earth Days (

[Image: Earth, as seen through NASA's Moderate Resolution Imaging Spectroradiometer aboard the Terra satellite.]