Monthly Seismicity Report For April 1, 2021 to April 30, 2021

During the month of April 2021, the Alaska Earthquake Center reported 3680 earthquakes within the state. The largest earthquake was magnitude 5.5 that occurred on April 8 at 09:10:18 AKST (April 8, 17:10:18 UTC), 17 miles SE of Cantwell. All earthquakes greater than magnitude 4.0 were located along the subduction zone, except a M4.4 that occured near Tanana. Activity is ongoing in the Simeonof, offshore Kodiak, Kaktovik, and Purcell Mountain areas. We saw an increase in glacial icequakes in the Prince William Sound and Yakutat Bay areas, around mid-April. Twelve earthquakes were reported as felt this month.

Notable Events in Descending Order of Magnitude

Magnitude 5.5, 17 miles SE of Cantwell, April 8 09:10:19 AKST
Magnitude 5.1, 98 miles NW of Attu, April 15 00:33:37 AKST
Magnitude 5.0, 42 miles N of Little Sitkin Pass, April 24 01:30:42 AKST
Magnitude 4.8, 9 miles NW of Elmendorf AFB, April 27 09:54:36 AKST
Magnitude 4.7, 38 miles S of Nikolski, April 7 11:31:55 AKST
Magnitude 4.4, 25 miles S of Tanana, April 30 09:19:24 AKST
Magnitude 4.3, 36 miles SE of Adak, April 6 01:02:26 AKST
Magnitude 4.1, 25 miles NE of Chenega Bay, April 27 09:26:01 AKST
Magnitude 4.1, 76 miles SE of Sand Point, April 10 23:10:50 AKST
Magnitude 4.0, 28 miles S of Atka Pass, April 23 17:26:27 AKST

This report was compiled by S. Cotton.

The data in this report are preliminary and subject to revision. The earthquake parameters have been determined by the AEC, with supplemental data provided by the USGS National Earthquake Information Center. The data are released on the condition that none of the cooperating agencies may be held liable for any damage resulting from its authorized or unauthorized use.

For more information on earthquakes and seismology, contact the AEC at (907)-474-7320.