Magnitude 3.5 - 84 miles N of Ambler
September 10, 2021 21:58:27 AKDT (September 11, 2021 05:58:27 UTC)
68.2939°N 158.2006°W Depth 11.5 miles (18 km)
This event has been reviewed by a seismologist
- 101 miles (163 km) N of Shungnak
- 102 miles (165 km) N of Kobuk
- 108 miles (175 km) NE of Kiana
- 120 miles (194 km) E of Red Dog Mine site
- 125 miles (202 km) NE of Noorvik
- 126 miles (204 km) N of Selawik
- 133 miles (215 km) NE of Noatak
- 151 miles (244 km) NE of Kotzebue
- 157 miles (254 km) SE of Point Lay
- 166 miles (269 km) W of Anaktuvuk Pass
- 168 miles (272 km) E of Kivalina
- Magnitude type: Ml2
- Event type: earthquake
Tectonic Setting of the Brooks Range
Seismicity in the Brooks Range is characterized by intraplate earthquakes associated with mountain building and crustal reorganization. A broad earthquake band extends from northeast of the Brooks Range toward the Beaufort Sea. Earthquake source mechanisms comprise a mixture of strike-slip and normal faulting events, indicative of north-northwest compression and northeast extension. A magnitude 6.4 earthquake on August 12, 2018 located 43 miles (69 km) south of Kaktovik was the largest earthquake ever recorded north of the Brooks Range. It produced an energetic aftershock sequence that continues to this day. In 2019, a vigorous swarm sequence began in the Purcell Mountains. More than 9,000 earthquakes have been recorded as part of this swarm through the end of 2021, including five earthquakes with magnitudes larger than 5. At present, this swarm continues, though at a decreased activity level.