Magnitude 3.9 - 32 miles NW of Talkeetna

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.