2024 Alaska Seismicity Summary

Abstract

The Alaska Earthquake Center reported 39,836 seismic events in Alaska and neighboring regions in 2024. The largest earthquakes were two magnitude 6.3 events that were part of a swarm of M6 events on December 8-9 in the Andreanof Islands region of Alaska. The first occurred on December 8 at 19:57:07 UTC, and the second occurred at 00:15:30 on December 9, followed by an M6.1 23 minutes later. Other strong earthquakes include two M6.0 events, one on May 19 and one on July 19, both south of Yunaska Island in the Islands of Four Mountains region of the Aleutians, and the strongest mainland earthquake, an M5.9, off the coast of Port Alexander in Southeast Alaska on January 12. We continued to monitor the 2020 M7.8 Simeonof sequence, but all other previous sequences and swarms have dropped below one event per day and are no longer being tracked. Numerous short-lived swarms occurred in 2024 and will be discussed below.