Chile Earthquake Shock Effect On Earth’s Axis May Have Created Shorter Days

The earthquake that took more than 700 lives in Chile on 27th Feb 2010 probably have changed the entire Earth’s rotation and shortened the length of days on our planet, a National Aeronautics and Space Administration scientist said.

The quake, the seventh strongest earthquake in recorded history, hit Chile Saturday and should have shortened the length of an Earth day by 1.26 microseconds (millionths of a second), according to research scientist Richard Gross at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

Chile earthquake may have shortened daysChile earthquake may have shortened days

Richard Gross, a geophysicist at Nasa’s Jet Propulsion Laboratory in Pasadena, California, said the 8.8 magnitude quake could have moved the Earth’s axis by 2.7 milliarcseconds (about 8cm) – enough to shorten a day by about 1.26 microseconds.

A large quake can shift huge amounts of rock and alter the distribution of mass on the planet. When that distribution changes, it changes the rate at which the planet rotates, which determines the length of a day.

The computer model used by Gross and his colleagues to determine the effects of the Chile earthquake effect also found that it should have moved Earth’s figure axis by about 3 inches (8 centimeters or 2.7 milliarcseconds).

Earth’s figure axis is not the same as its north-south axis, which it spins around once every day at a speed of about 1,000 mph (1,604 kilometers per hour). The figure axis is the axis around which Earth’s mass is balanced. It is offset from the Earth’s north-south axis by about 33 feet (10 meters).

Strong earthquakes have altered Earth’s days and its axis in the past. The magnitude-9.1 Sumatran earthquake in 2004, which set off a deadly tsunami, should have shortened Earth’s days by 6.8 microseconds and shifted its axis by about 2.76 inches (7 centimeters, or 2.32 milliarcseconds).

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