On Sunday morning at 6:58 Alaska time, we recorded a magnitude 6.4 earthquake 52 miles southwest of Kaktovik. It was, by a wide margin, the largest earthquake ever recorded north of the Brooks Range in Alaska. This earthquake started a vigorous aftershock sequence, including a magnitude 6.0 earthquake at 1:15pm—the second largest ever recorded north of the Brooks Range.

We will keep this summary updated as the sequence develops. Our evolving content page, where we collect new figures, maps, and analysis, is here.

The epicenter was in the remote Sadlerochit Mountains, about 25 miles south of the Beaufort Sea coast. We have received no reports of damage or injuries, and Alyeska reports there was no impact on pipeline operations. The earthquake was felt widely, though, with reports coming in from Kaktovik west to Nuiqsut and as far south as Fairbanks.