Sunday’s(3rd november 2002) magnitude 7.9 earthquakes in central Alaska created a scar across the landscape for more than 145 miles, according to surveys conducted the past two days by geologists from the U.S. Geological Survey and the Alaska Division of Geological and Geophysical Survey.
The geologists, who followed the earthquake rupture by helicopter through valleys, across streams, and along glaciers, measured a maximum horizontal offset of 22 feet across the Tok Highway Cutoff, a road that goes from Tok to Glenallen and intersects with the Alaska Highway.
This earthquake, one of the largest ever recorded on U.S. soil, occurred on the Denali fault system, one of the longest strike-slip fault systems in the world, rivaling in size California’s famed San Andreas strike-slip fault system.
Peter Haeussler, the USGS scientist helping lead the surveys, noted that when the Trans-Alaska Pipeline was constructed, no clear surface features existed that revealed the exact position of the Denali fault where it crosses the pipeline corridor. New surface ruptures after Sunday’s quake demonstrate that even though it is now clear that the structures engineered to accommodate fault movement are largely north of the fault trace, the pipeline engineering design was robust, functioned well, and resulted in minimal earthquake damage.