Tsunami Quake was Detected Everywhere...
- ...even in Tristan
New York Times
Quake Lifted Earth's Surface Around Globe
or, How to Get Your Name in the New York Times
By WILLIAM J. BROAD
Published: January 13, 2005
New studies of the giant earthquake that produced devastating tsunamis in the Indian Ocean show that its shock waves
ricocheted around the globe for hours and lifted the earth's surface nearly an inch even half a world away.
"They're like ripples in a pond," Dr. Richard C. Aster, a geophysicist at the New Mexico Institute of Mining and Technology,
said yesterday. "But the pond is a sphere, so they keep going around and around."
Dr. Aster, who compiled seismograms to measure the shock waves at increasing distances from the quake's epicenter, said the
waves were 1,000 times the size of those that seismologists customarily measure.
The colossal jolt struck Dec. 26 off the west coast of northern Sumatra, and the shock waves radiated out through the
earth's rocky interior, traveling faster than waves do in air or water. Dr. Aster used data gathered by a global network of
seismometers run by the Incorporated Research Institutions for Seismology, or IRIS, a consortium based in Washington that is
financed mainly by the National Science Foundation. IRIS has nearly 150 member institutions at universities in the United
States and abroad.
The closest readings came from the Australian Cocos Islands, south of Sumatra, and Sri Lanka, and the farthest from Ecuador.
The seismic data show the waves traveling around the earth for six hours.
Dr. Aster said that even in Ecuador, the shock wave displaced the earth's surface more than two centimeters, or nearly an
inch, but the movement was too slow to be perceptible to humans. The jolt was much sharper in Pallekele, Sri Lanka, and
shook the ground over a range of nearly four inches, he said.
Waves from the quake weakened as they bounced around the globe but were still discernible after making a complete loop. The
seismogram from Tristan da Cunha, a group of British islands in the South Atlantic, shows the main wave arriving after a
little more than an hour, then two smaller ones that circled the earth in two directions arriving after about 120 minutes
and 230 minutes.
Copyright 2005 The New York Times Company
Bob's entry for the 2005 Curmudgeon Award:
Dr. Aster seems to have done what the Nuclear Test Ban Treaty
observers do every day in Vienna: turned on his computer and
looked at seismic telemetry data from all over the world,
noting the time and location of the waves. I think the main
difference is the guys in Vienna didn't call the Times.
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