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[Phys-L] Re: earthquake



The following quotation is from the Chicago Tribune on-line edition.

* * * <quotation from Tom Skilling> * * *
Incredibly, the magnitude 9.0 earthquake that struck off Sumatra on
Sunday morning caused a vertical displacement of so much material that
the rotation period of the Earth has been permanently altered. By a tiny
but measurable amount, the Earth is now rotating more quickly on its
axis, and the 24-hour day is now one ten-thousandth second
shorter.That's the result of calculations based on preliminary data made
by Oak Park astronomer Dr. Leslie M. Golden. It's analogous to the
increase in rotational speed that a twirling ice skater experiences when
he or she draws in their arms. It is estimated that during the Sumatran
quake, a block of material roughly 600 miles in length and 100 miles in
width fell 30 feet closer to the Earth's axis of rotation. The planet
has responded by rotating more rapidly, albeit ever so slightly, and our
24-hour days are now one ten-thousandth second shorter.

Tom Skilling is chief meteorologist at WGN-TV. His forecasts can be seen
Monday through Friday on WGN-TV News at noon and 9 p.m.

* * * < end quote > * * *

Michael D. Edmiston, Ph.D.
Professor of Chemistry and Physics
Bluffton University
Bluffton, OH 45817
(419)-358-3270
edmiston@bluffton.edu