2021 Alaska Seismicity Summary

Natalia Ruppert et al.
Wed, 22 Apr 2026 17:17:26 PDT

The Alaska Earthquake Center reported 49,120 seismic events in Alaska and neighboring regions in 2021. The largest earthquake was a magnitude 8.2 event that occurred on July 29 southwest of Kodiak Island. It was followed by about 1,300 aftershocks including two magnitude 6.9 events on August 14 and October 11. Other active spots include sequences near Harding Lake in Interior Alaska in July-September and near Yakutat Bay in September. The largest earthquake in mainland Alaska was the M6.1 Chickaloon Earthquake on May 31. We continued to monitor ongoing activity within the 2018 M7.1 Anchorage, 2018 M6.4 Kaktovik, and 2018 M7.9 Offshore Kodiak aftershock sequences, the Purcell Mountains earthquake swarm, and the Wright Glacier cluster northeast of Juneau.