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The 2002 Denali earthquake
2002 Denali earthquake

The 2002 Denali earthquake occurred at 22:12:41 UTC November 3, 2002, with an epicenter 66 km ESE of Denali National Park, Alaska. This 7.9 Moment magnitude scale earthquake was the largest recorded in the interior of the United States for more than 150 years....
 occurred at 22:12:41 UTC (1:12 PM Local Time
Alaska Time Zone

The Alaska Time Zone observes standard time by subtracting nine hours from Coordinated Universal Time . During daylight saving time its time offset is only eight hours ....
) November 3, 2002, with an epicenter
Epicenter

The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates....
 66 km ESE of Denali National Park, Alaska
Alaska

Alaska is the largest U.S. state of the United States by area; it is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait....
. This 7.9 Mw
Moment magnitude scale

The moment magnitude scale is used by seismologists to measure the size of earthquakes in terms of the energy released. The scale was developed in the 1970s to succeed to 1930s-era Richter magnitude scale....
 earthquake was the largest recorded in the interior of the United States
United States

The United States of America is a Federal government constitutional republic comprising U.S. state and a federal district. The country is situated mostly in central North America, where its Contiguous United States and Washington, D.C., the Capital districts and territories, lie between the Pacific Ocean and Atlantic Oceans, Borders of the U...
 for more than 150 years. The shock was the strongest ever recorded in the interior of Alaska. There were no fatalities and only a few injuries due to the remote location.


Minor damage was reported over a wide area but the only examples of severe damage were on highways that crossed the fault trace and areas that suffered liquefaction
Liquefaction

Liquefaction may refer to:* Soil liquefaction, the process by which sediments become suspended* Liquefaction of gases in physics, chemistry, and thermal engineering...
, e.g.






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The 2002 Denali earthquake
2002 Denali earthquake

The 2002 Denali earthquake occurred at 22:12:41 UTC November 3, 2002, with an epicenter 66 km ESE of Denali National Park, Alaska. This 7.9 Moment magnitude scale earthquake was the largest recorded in the interior of the United States for more than 150 years....
 occurred at 22:12:41 UTC (1:12 PM Local Time
Alaska Time Zone

The Alaska Time Zone observes standard time by subtracting nine hours from Coordinated Universal Time . During daylight saving time its time offset is only eight hours ....
) November 3, 2002, with an epicenter
Epicenter

The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates....
 66 km ESE of Denali National Park, Alaska
Alaska

Alaska is the largest U.S. state of the United States by area; it is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait....
. This 7.9 Mw
Moment magnitude scale

The moment magnitude scale is used by seismologists to measure the size of earthquakes in terms of the energy released. The scale was developed in the 1970s to succeed to 1930s-era Richter magnitude scale....
 earthquake was the largest recorded in the interior of the United States
United States

The United States of America is a Federal government constitutional republic comprising U.S. state and a federal district. The country is situated mostly in central North America, where its Contiguous United States and Washington, D.C., the Capital districts and territories, lie between the Pacific Ocean and Atlantic Oceans, Borders of the U...
 for more than 150 years. The shock was the strongest ever recorded in the interior of Alaska. There were no fatalities and only a few injuries due to the remote location.

Earthquake damage

Trans Alaska Pipeline Denali Fault Shift


Minor damage was reported over a wide area but the only examples of severe damage were on highways that crossed the fault trace and areas that suffered liquefaction
Liquefaction

Liquefaction may refer to:* Soil liquefaction, the process by which sediments become suspended* Liquefaction of gases in physics, chemistry, and thermal engineering...
, e.g. Northway Airport
Northway Airport

Northway Airport is a public airport located in Northway, Alaska, in the Southeast Fairbanks Census Area, Alaska, Alaska, United States....
. Several bridges were damaged but none so severely that they were closed to traffic.

The Trans-Alaska Pipeline System
Trans-Alaska Pipeline System

The Trans-Alaska Pipeline System , usually called the Alyeska Pipeline in Alaska or the Alaska Pipeline elsewhere, is a major United States Petroleum pipeline transport connecting oil fields in Alaska's North Slope to a North Pacific seaport where the oil can be shipped to the Lower 48 states for refining....
 crossed the rupture trace and the pipeline suffered some minor damage. There was no oil spillage as the pipeline at that location had been designed to withstand just such an event. The pipeline was shut down for 3 days to allow for inspections but was then reopened.

Tectonic setting

The Denali-Totschunda fault is a major dextral (right lateral) strike-slip system, similar in scale to the San Andreas fault
San Andreas Fault

The San Andreas Fault is a geologic transform fault that runs a length of roughly 800 miles through California in the United States. The fault's motion is dextral strike-slip ....
 system.

In Alaska, moving from east to west, the plate interactions change from a transform boundary between Pacific and North American plates to a collision zone with a microplate, the Yakutat terrane
Yakutat Block

The Yakutat Block is a terrane in the process of accreting to the North American continent along the south central coast of Alaska. It has been displaced about 600 km northward since the Cenozoic along the Queen Charlotte-Fairweather fault system....
, which is in the process of being accreted to the North American plate, to a destructive boundary along the line of the Aleutian islands
Aleutian Islands

The Aleutian Islands are a chain of more than 300 small volcanic islands forming a volcanic arc in the Northern Pacific Ocean, occupying an area of 6,821 sq mi and extending about 1,200 mi westward from the Alaska Peninsula toward the Kamchatka Peninsula....
. The Denali-Totschunda fault system is one of the structures that accommodate the accretion of the Yakutat terrane.

Earthquake characteristics

On October 23, 2002, there was a magnitude 6.7 earthquake located on the Denali fault. Because of its location close to the November 3 event and the fact that it preceded it by only 11 days, this earthquake is regarded as a foreshock
Aftershock

An aftershock is an earthquake that occurs after a previous earthquake . An aftershock is in the same region of the main shock but is always of smaller magnitude strength....
 that probably directly triggered the main shock.

The initial rupture on November 3 was on a thrust fault segment, the previously unknown Susitna Glacier thrust, to the south of the Denali fault. The epicenter lies just east of the October 23 foreshock. The rupture then jumped to the main Denali fault strand propagating for a further before jumping again onto the Totschunda fault and rupturing another of fault plane. The total surface rupture was ca. .

There is evidence of local supershear
Supershear earthquake

A supershear earthquake is an earthquake in which the propagation of the rupture along the fault surface occurs at speeds in excess of the seismic S-wave velocity....
 propagation inferred from ground motions.

See also

  • Good Friday earthquake
    Good Friday Earthquake

    The 1964 Alaska earthquake, also known as the Great Alaska earthquake, began at 5:36 P.M. AST on Friday, March 27, 1964. Across south-central Alaska, ground fissures, collapsing buildings, and tidal waves directly caused about 131 deaths....


External links

  • USGS page on the 2002 Denali Earthquake