The Denali Fault is the principal intracontinental strike-slip fault of interior Alaska — a direct analog of California's San Andreas, accommodating the westward extrusion of southern Alaska as the Yakutat terrane collides with the continent. On November 3, 2002, it produced a M7.9 earthquake, the largest strike-slip earthquake in North America in almost 150 years, with about 340 km of surface rupture across three faults. The rupture crossed beneath the Trans-Alaska Oil Pipeline — and the pipeline survived.
The Denali fault is in Alaska, which the USGS covers with its own 2023 hazard model; this site uses the model for the conterminous United States, so it is not listed here.
The M7.9 struck on November 3, 2002, about 90 miles south of Fairbanks, at a depth of about 4 km. It produced roughly 340 km of surface rupture across the Susitna Glacier, Denali, and Totschunda faults, with maximum right-lateral offset of about 8.8 meters (~29 feet) near the Totschunda junction. It was preceded 10 days earlier by a M6.7 Nenana Mountain foreshock on the Denali fault. The quake was felt and detected thousands of miles away — seiches sloshed in Seattle's Lake Union and Lake Pontchartrain, and it triggered seismicity as far as Yellowstone.
The 2002 earthquake was the first well-documented supershear continental earthquake: after propagating about 120 km at ~3.3 km/s, the rupture accelerated to ~5 km/s — faster than the shear-wave speed (over 7,000 mph). It also nucleated on a previously unknown blind thrust, the Susitna Glacier fault, before jumping onto the strike-slip Denali fault (a slip-partitioned initiation). The rupture exactly re-occupied an older rupture that geologists had documented in the 1970s.
The rupture crossed beneath the Trans-Alaska Oil Pipeline, then carrying about 17% of U.S. domestic oil supply. The pipeline shifted about 4.3 meters (~14 feet) of fault offset without breaking — the first real-world test of fault-offset engineering design, which was based on 1970s USGS geologic studies. Slip rates along the fault run about 8–13 mm/yr (western 9.4, central 12.1, eastern 8.4 mm/yr), decreasing eastward. Recurrence of M7.9-class events on the central segment is estimated at roughly 600 years.
Population along the fault is sparse, but Fairbanks shook violently in 2002 and Anchorage and Fairbanks would face serious shaking in a nearer or larger event. See the Alaska page and our seismic risk lookup.