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Alaska shook, mountains spoke

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11:46am, December 22, 2003

From San Francisco, at a meeting of the American Geophysical Union

The largest inland earthquake to strike North America in more than a century shook south central Alaska on Nov. 3, 2002 (SN: 11/16/02, p. 307: Available to subscribers at Shaked Alaska: A sleepy fault wakes and reveals new links). Small pulses in atmospheric pressure detected in Fairbanks soon after the quake suggest that the magnitude 7.9 temblor literally moved mountains, briefly turning them into 3-kilometer-tall granite loudspeakers.

The quake began at a site along the Denali fault about 135 km south of Fairbanks. From there, the slippage sped toward the southeast along the fault at a rate of about 3.3 km per second, says geophysicist Charles R. Wilson of the University of Alaska in Fairbanks. At some spots along the total 320-km slippage, fault surfaces suddenly moved almost 9 meters past each other.

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