The most serious earthquake risk is the Denali Fault
, which crosses the Parks Highway near Cantwell, just 35 miles south of where the gas line crosses the Nenana River near Denali National Park.
This reference is centered on four major themes: subduction and great earthquakes of the Aleutian Arc, the transition from strike slip to accretion and subduction of the Yakutat microplate, the Denali fault
and related formations and their part in permanent deformation of the overriding plate, and regional integration and large-scale models as well as existing data to address global questions and theories.
At the site believed to have the highest risk, where the pipeline crosses the Denali fault
zone, the pipe is on lowered risers that rest on elongated skids, allowing for up to twenty feet of lateral and five feet of vertical movement.
Beroza's interest in the topic was rekindled with recent observations of three huge supershear earthquakes--the magnitude 7.4 that devastated Turkey in 1999; the 8.1 that rocked Tibet in 2001; and the 7.9 that followed the rupture of the Denali Fault
in Alaska in 2002.
Alaska's Denali fault
(boundary along which rocks slide past each other) suddenly shifted, generating powerful seismic waves (vibrating energy waves that travel through the ground).
The quake began at a site along the Denali fault
about 135 km south of Fairbanks.
At 7.9 on the Richter magnitude scale, the Denali Fault
Earthquake reverberated throughout Alaska and continued releasing energy far to the southeast of its epicenter.
The earthquake, among the largest ever experienced in the U.S., occurred on the Denali fault
, one of the longest strike-slip fault systems that cuts through a continent anywhere in the world.
Luckily, no one was injured by the earthquake that struck along the Denali Fault
Line and measured 7.9 on the Richter Scale.
In the mid-1990s, Great Northwest branched out into road construction and has left its mark on Interior Alaska's highways, as well as a major rebuild of the Tok Cutoff after the 7.9 magnitude Denali Fault
Earthquake in 2002.
* Special designs were considered for the section of the pipeline that was to traverse the Denali Fault
region to ensure that it could withstand an earthquake similar to the great quake of 1964.
The earthquake occurred on the Denali Fault
and was preceded by a 6.7 earthquake 11 days earlier.