The earthquake in Chile that killed more than 700 people Saturday probably shifted Earth’s axis and shortened the day, a National Aeronautics and Space Administration scientist said.
Earthquakes can involve shifting hundreds of kilometers of rock by several meters, changing the distribution of mass on the planet.
That affects Earth’s rotation, said Richard Gross, a geophysicist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., who uses a computer model to calculate the effects.
“The length of the day should have gotten shorter by 1.26 microseconds (millionths of a second),” Gross said Monday in an e-mailed reply to questions. “The axis about which the Earth’s mass is balanced should have moved by 2.7 milliarcseconds (about 8 centimeters, or 3 inches).”
The changes can be modeled, though they’re difficult to physically detect given their small size, Gross said.
