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| Date | November 3, 2002 |
|---|---|
| Magnitude | 7.9 Mw |
| Depth | 5 km |
| Epicenter location | Denali National Park, Alaska |
| Countries/ regions affected |
United States |
| Casualties | No fatalities |
The 2002 Denali earthquake occurred at 22:12:41 UTC (1:12 PM Local Time) November 3, 2002, with an epicenter 66 km ESE of Denali National Park, Alaska. This 7.9 Mw earthquake was the largest recorded in the interior of the United States for more than 150 years. The shock was the strongest ever recorded in the interior of Alaska.[1] There were no fatalities and only a few injuries due to the remote location.
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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, e.g. Northway Airport[2]. Several bridges were damaged but none so severely that they were closed to traffic.
The Trans-Alaska Pipeline System 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.
The Denali-Totschunda fault is a major dextral (right lateral) strike-slip system, similar in scale to the San Andreas fault 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, which is in the process of being accreted to the North American plate, to a destructive boundary along the line of the Aleutian islands. The Denali-Totschunda fault system is one of the structures that accommodate the accretion of the Yakutat terrane.
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 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,[3] to the south of the Denali fault. The epicenter lies just 25 kilometres (16 mi) east of the October 23 foreshock. The rupture then jumped to the main Denali fault strand propagating for a further 220 kilometres (137 mi) before jumping again onto the Totschunda fault and rupturing another 70 kilometres (43 mi) of fault plane. The total surface rupture was ca. 340 kilometres (211 mi).
There is evidence of local supershear propagation inferred from ground motions.[4]
  | AEIC page on the Denali earthquake - M 7.9 Denali fault earthquake of November 3, 2002 |
| | The 2002 Denali Fault earthquake Magnitude 7.9 near Denali National Park, AK - The 2002 Denali Fault earthquake Magnitude 7.9 near Denali National Park, AK |
| | Crone,A.J., Personius,S.F., Craw,P.A., Haeussler,P.J. & Staft,L,.A. 2004.The Susitna Glacier Thrust Fault: Characteristics of Surface Ruptures on the Fault that Initiated the 2002 Denali Fault Earthquake. Bulletin of the Seismological Society of America; v. 94; p. S5-S22. - The Susitna Glacier Thrust Fault: Characteristics of Surface Ruptures on the Fault that Initiated the 2002 Denali Fault Earthquake -- Crone et al. 94 (6): S5 -- Bulletin of the Seismological Society of America |
| | Dunham,E.M. & Archuleta,R.J. 2004.Evidence for a Supershear Transient during the 2002 Denali Fault Earthquake, Bulletin of the Seismological Society of America, 92, S256-S268 - Evidence for a Supershear Transient during the 2002 Denali Fault Earthquake -- Dunham and Archuleta 94 (6): S256 -- Bulletin of the Seismological Society of America |
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