a Sunday afternoon in November of 2002, an earthquake of magnitude
7.9 occurred in south-central Alaska. It was one of the largest
recorded earthquakes in the United States, and rocked boats as far
away as Louisiana. The quake originated on the Denali-Totschunda
fault system, a strike-slip fault zone that curves for over 700km
(434 miles) through Alaska into Canada, and, like the San Andreas
fault system, results from the interaction between the Pacific plate
and the North American plate. Part of the fault system is shown
here, with the Denali fault outlined in red and the Totschunda fault
outlined in orange. In general, the earth to the north of the fault
system is moving east relative to the ground south of the fault.
This was the case during the November 2002 earthquake, where the
eastward horizontal shift of the ground measured up to 6.6 meters
(22 feet). The earthquake triggered rock and snow slides, and formed
a rupture about 323 km (200 miles) in length that passed beneath
the Trans-Alaska Oil Pipeline.
photograph shows a highway near Tok, Alaska, that has been affected
by the fault. Researchers estimated the horizontal offset of the
road to be about 6.6 m (22 ft). This picture was taken by Peter
Haeussler of the USGS. More information can be found on a USGS
Earthquake Hazards Program news page as well as in the
Fault Earthquake Fact Sheet. This and other photographs
can be found here.