Earthquakes room commonplace throughout much of Alaska. On mean there is a size 7 or higher earthquake what in or offshore Alaska every 1 to 2 years and a magnitude 8 or greater quake around every 13 years. This quakes take place as a an outcome of stresses resulted in by motions of tectonic plates that comprise the Earth"s outer shell. In this region, the Pacific Plate moves steadily northward in ~ a rate of about 2 inches every year and also descends, or "subducts," in ~ the phibìc American Plate.
You are watching: How often does alaska have earthquakes
one irregularity on top of the Pacific Plate, recognized as the Yakutat block (YAK), impedes smooth subduction of the Pacific Plate and has caused a wedged-shaped piece of the phibìc American Plate, the Wrangell Subplate, come break loosened and turn counterclockwise. The west Alaska Range, which has Mount McKinley, the greatest peak in north America, is a zone of compression between the phibìc American Plate and also the Wrangell Subplate. The Denali and Totschunda Faults type the northeastern margin that the Wrangell Subplate.
The biggest earthquakes in the an ar (magnitudes 8 and 9) occur along the subduction zone and also often generate disastrous tsunamis (seismic sea waves). These include the 2nd largest quake ever before recorded worldwide, the 1964 size 9.2 Prince william Sound earthquake, i beg your pardon killed an ext than 100 Alaskans. Generally smaller but still an effective quakes (magnitudes 6 to 8), such as the November 2002 Denali fault earthquake, take place inland follow me faults choose the Denali, Totschunda, and Castle hill Faults.
|This photo shows the 2002 Denali error rupture about 1.5 mile west of the Trans-Alaska Oil Pipeline. The floor on the left side of the cracks moved away indigenous the viewer around 15 feet, resulting in this large gap to open. |
See more: How Much Does The Ceo Of Planned Parenthood Make, Planned Parenthood Head Hit For Six
|The 2002 Denali error earthquake developed on a "strike-slip" fault (in which the two sides slip horizontally past each other), like the mountain Andreas error in California. This Alaska quake was comparable in size (M) and also in size of fault ruptured to three major quakes on the san Andreas fault in the past few centuries.|
| Denali error Earthquake fact Sheet main page | Pipeline Sidebar | Shakemap Sidebar | southerly Alaska Earthquakes Sidebar |