Tectonic Setting of the Denali Fault
The Denali Fault is a major intracontinental right-lateral strike-slip fault that partially
accomodates the oblique collision of the Yakutat block into Alaska's margin, extending from
northwestern British Columbia to the central and western regions of Alaska. The largest earthquake
recorded on the Denali Fault was a M7.9 on November 3, 2002. Its rupture extended for nearly 210
miles along the central Denali Fault system. This event was preceded by the M6.7 Nenana Mountain
earthquake on October 23, which ruptured 25 miles of the Denali Fault west of the M7.9 event. It
is typical behavior of these major right-lateral faults to produce very low background levels of
seismicity between large ruptures hundreds of years apart that are followed by multi-year aftershock
sequences. Another notable feature associated with the Denali Fault system is the Kantishna seismic
cluster, located just north of the main fault trace inside Denali National Park. This cluster produces
tens of small, shallow earthquakes every day. The largest known earthquakes in this cluster are on the
order of magnitude 5, but those are rare. This cluster is believed to accommodate deformation between
the Denali Fault and the Minto Flats seismic zone to the north.
