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Chile Quake May Have Shifted Earth’s Axis

March 2, 2010

Chile Earthquake May Have Shortened Days on Earth

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  • Clinton visits quake-hit Chile AFP – View of a car trapped in rubble after a tsunami hit the Chilean town of San Antonio on February 28. US … Staff Staff

    space.com2 hrs 24 mins ago

    The massive 8.8 earthquake that struck Chile may have changed the entire Earth’s rotation and shortened the length of days on our planet, a NASA scientist said Monday.

    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 milliseconds, according to research scientist Richard Gross at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

    “Perhaps more impressive is how much the quake shifted Earth’s axis,” NASA officials said in a Monday update.

    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 cm or 27 milliarcseconds).  

    The 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 kph).

    The figure axis is the axis around which the 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 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 cm, or 2.32 milliarcseconds).

    One Earth day is about 24 hours long. Over the course of a year, the length of a day normally changes gradually by one millisecond. It increases in the winter, when the Earth rotates more slowly, and decreases in the summer, Gross has said in the past.

    The Chile earthquake was much smaller than the Sumatran temblor, but its effects on the Earth are larger because of its location. Its epicenter was located in the Earth’s mid-latitudes rather than near the equator like the Sumatran event.

    The fault responsible for the 2010 Chile quake also slices through Earth at a steeper angle than the Sumatran quake’s fault, NASA scientists said.

    “This makes the Chile fault more effective in moving Earth’s mass vertically and hence more effective in shifting Earth’s figure axis,” NASA officials said.

    Gross said his findings are based on early data available on the Chile earthquake. As more information about its characteristics are revealed, his prediction of its effects will likely change.

    The Chile earthquake has killed more than 700 people and caused widespread devastation in the South American country.

    Several major telescopes in Chile’s Atacama Desert have escaped damage, according to the European Southern Observatory managing them.

    A salt-measuring NASA satellite instrument destined to be installed on an Argentinean satellite was also undamaged in the earthquake, JPL officials said.

    The Aquarius instrument was in the city of Bariloche, Argentina, where it is being installed in the Satelite de Aplicaciones Cientificas (SAC-D) satellite. The satellite integration facility is about 365 miles (588 km) from the Chile quake’s epicenter.

    The Aquarius instrument is designed to provide monthly global maps of the ocean’s salt concentration in order to track current circulation and its role in climate change. offers rich and compelling content about space science, travel and exploration as well as astronomy, technology, business news and more. The site boasts a variety of popular features including our space image of the day and other space pictures,space videos, Top 10s, Trivia, podcasts and Amazing Images submitted by our users. Join our community, sign up for our free newsletters and register for our RSS Feeds today!

    2 Comments leave one →
    1. March 2, 2010 1:32 pm

      Never, ever think you shouldn’t write. You are a very, very good writer and have a lot to tell. Please, please don’t give it up. I will cross all my fingers, toes, eyes etc that you get it all back. But, if you don’t, maybe wait a while and then get back to re-writing the lost part.

    2. Jennifer Shipley permalink
      March 3, 2010 1:58 am

      I just caught this error by the OP at He/she misunderstood Richard Gross. He states, “It (the length of day) increases in the winter, when the Earth ROTATES more slowly, and decreases in the summer…” Actually the speed the earth ROTATES doesn’t change. And who’s winter is the OP referring to? Let me explain:

      The winter they are referring to is the Northern Hemisphere’s winter, and the Earth doesn’t rotate more slowly, the speed of it’s orbit around the sun is slower in the winter due to it’s elliptical path, so it has to rotate more than 360 degrees to complete one day. There is no change in the speed at which it rotates (spins on its axis.)

      This is exactly why I say, “You can’t believe everything you read.” I find major errors in scientific info posted and reposted from reputable sources like kiro and komo, and people quote these documents as if they are The Gospel Truth, “because Komo said so.”

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