Earthquakes are commonplace throughout much of Alaska. On median there is a magnitude 7 or higher earthquake what in or offshore Alaska every 1 to 2 years and also a magnitude 8 or greater quake around every 13 years. These quakes occur as a result of stresses brought about by motions of tectonic bowl that make up the Earth"s outer shell. In this region, the Pacific Plate move steadily northward in ~ a price of about 2 inches per year and also descends, or "subducts," in ~ the phibìc American Plate.
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one irregularity on height of the Pacific Plate, recognized as the Yakutat block (YAK), impedes smooth subduction of the Pacific Plate and has caused a wedged-shaped item of the phibìc American Plate, the Wrangell Subplate, come break loosened and rotate counterclockwise. The west Alaska Range, which contains Mount McKinley, the greatest peak in phibìc America, is a zone of compression between the phibìc American Plate and the Wrangell Subplate. The Denali and also Totschunda Faults form the northeastern margin of the Wrangell Subplate.
The biggest earthquakes in the an ar (magnitudes 8 and 9) occur along the subduction zone and also often generate destructive tsunamis (seismic sea waves). These include the second largest quake ever recorded worldwide, the 1964 size 9.2 Prince william Sound earthquake, i beg your pardon killed an ext than 100 Alaskans. Normally smaller yet still powerful quakes (magnitudes 6 come 8), such together the November 2002 Denali error earthquake, take place inland along faults choose the Denali, Totschunda, and Castle mountain Faults.
|This photograph shows the 2002 Denali fault rupture about 1.5 miles west that the Trans-Alaska Oil Pipeline. The ground on the left side of the cracks relocated away native the viewer around 15 feet, resulting in this large gap to open. |
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|The 2002 Denali fault earthquake arisen on a "strike-slip" error (in i beg your pardon the two sides slip horizontally past each other), prefer the mountain Andreas error in California. This Alaska quake was similar in size (M) and also in size of error ruptured come three significant quakes ~ above the mountain Andreas fault in the past couple of centuries.|
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