Turn Off Ads?
Results 1 to 8 of 8

Thread: NASA: Indonesian Earthquake changed Earth's rotation, moved the North Pole

Threaded View

  1. #1
    Smells Like Teen Spirit jmcclain19's Avatar
    Join Date
    Apr 2004
    Location
    Phoenix
    Posts
    6,490

    NASA: Indonesian Earthquake changed Earth's rotation, moved the North Pole

    http://biz.yahoo.com/prnews/050110/dcm017_1.html

    NASA Details Earthquake Affects on the Earth
    Monday January 10, 11:26 am ET


    WASHINGTON, Jan. 10 /PRNewswire/ -- NASA scientists using data from the Indonesian earthquake calculated it affected Earth's rotation, decreased the length of day, slightly changed the planet's shape, and shifted the North Pole by centimeters. The earthquake that created the huge tsunami also changed the Earth's rotation.
    Dr. Benjamin Fong Chao, of NASA's Goddard Space Flight Center, Greenbelt, Md. and Dr. Richard Gross of NASA's Jet Propulsion Laboratory, Pasadena, Calif. said all earthquakes have some affect on Earth's rotation. It's just they are usually barely noticeable.

    "Any worldly event that involves the movement of mass affects the Earth's rotation, from seasonal weather down to driving a car," Chao said.

    Chao and Gross have been routinely calculating earthquakes' effects in changing the Earth's rotation in both length-of-day as well as changes in Earth's gravitational field. They also study changes in polar motion that is shifting the North Pole. The "mean North pole" was shifted by about 2.5 centimeters (1 inch) in the direction of 145 degrees East Latitude. This shift east is continuing a long-term seismic trend identified in previous studies.

    They also found the earthquake decreased the length of day by 2.68 microseconds. Physically this is like a spinning skater drawing arms closer to the body resulting in a faster spin. The quake also affected the Earth's shape. They found Earth's oblateness (flattening on the top and bulging at the equator) decreased by a small amount. It decreased about one part in 10 billion, continuing the trend of earthquakes making Earth less oblate.

    To make a comparison about the mass that was shifted as a result of the earthquake, and how it affected the Earth, Chao compares it to the great Three-Gorge reservoir of China. If filled the gorge would hold 40 cubic kilometers (10 trillion gallons) of water. That shift of mass would increase the length of day by only 0.06 microseconds and make the Earth only very slightly more round in the middle and flat on the top. It would shift the pole position by about two centimeters (0.8 inch).

    The researchers concluded the Sumatra earthquake caused a length of day (LOD) change too small to detect, but it can be calculated. It also caused an oblateness change barely detectable, and a pole shift large enough to be possibly identified. They hope to detect the LOD signal and pole shift when Earth rotation data from ground based and space-borne position sensors are reviewed.

    The researchers used data from the Harvard University Centroid Moment Tensor database that catalogs large earthquakes. The data is calculated in a set of formulas, and the results are reported and updated on a NASA Web site.

    The massive earthquake off the west coast of Indonesia on December 26, 2004, registered a magnitude of nine on the new "moment" scale (modified Richter scale) that indicates the size of earthquakes. It was the fourth largest earthquake in one hundred years and largest since the 1964 Prince William Sound, Alaska earthquake.

    The devastating mega thrust earthquake occurred as a result of the India and Burma plates coming together. It was caused by the release of stresses that developed as the India plate slid beneath the overriding Burma plate. The fault dislocation, or earthquake, consisted of a downward sliding of one plate relative to the overlying plate. The net effect was a slightly more compact Earth. The India plate began its descent into the mantle at the Sunda trench that lies west of the earthquake's epicenter. For information and images on the Web, visit:

    http://www.nasa.gov/vision/earth/loo...sia_quake.html
    Last edited by jmcclain19; 01-10-2005 at 06:57 PM.


Turn Off Ads?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Board Moderators may, at their discretion and judgment, delete and/or edit any messages that violate any of the following guidelines: 1. Explicit references to alleged illegal or unlawful acts. 2. Graphic sexual descriptions. 3. Racial or ethnic slurs. 4. Use of edgy language (including masked profanity). 5. Direct personal attacks, flames, fights, trolling, baiting, name-calling, general nuisance, excessive player criticism or anything along those lines. 6. Posting spam. 7. Each person may have only one user account. It is fine to be critical here - that's what this board is for. But let's not beat a subject or a player to death, please.

Thank you, and most importantly, enjoy yourselves!


RedsZone.com is a privately owned website and is not affiliated with the Cincinnati Reds or Major League Baseball


Contact us: Boss | GIK | BCubb2003 | dabvu2498 | Gallen5862 | LexRedsFan | Plus Plus | RedlegJake | redsfan1995 | The Operator | Tommyjohn25