Monthly Seismicity Report For August 1, 2021 to August 31, 2021

During the month of August 2021, the Alaska Earthquake Center reported 4950 earthquakes within the state. The largest earthquake was magnitude 6.9 that occurred on August 14 at 03:57:44 AKST (August 14, 11:57:44 UTC), 84 miles SE of Perryville. It was an aftershock of M8.2 Chignink earthquake on July 29, 2021. During August we located about 450 aftershocks of that big event. All other earthquakes of magnitude 4.0 and greater occured along the subduction zone, except two events of M4.1 and 4.2 in Chukchi Sea and a M4.1 at McCarthy.  The glacial activity was ongoing in Prince William Sound, Icy Bay, Yakutat Bay, and at Mt. Ogden in south-east. There were about 50 swarmed events of magnitude 1.5-3.2 located at Mt. Ogden. Ten earthquakes were reported as felt .

Notable Events in Descending Order of Magnitude

Magnitude 6.9, 84 miles SE of Perryville, August 14 03:57:44 AKST
Magnitude 5.2, 64 miles S of Buldir Is, August 8 06:50:27 AKST
Magnitude 5.0, 127 miles W of Attu, August 9 01:42:03 AKST
Magnitude 4.6, 42 miles SE of Mt. Gareloi, August 22 03:45:02 AKST
Magnitude 4.5, 40 miles SE of Perryville, August 24 17:31:27 AKST
Magnitude 4.4, 48 miles SE of Perryville, August 1 07:27:40 AKST
Magnitude 4.4, 47 miles SE of Mt. Recheshnoi, August 17 09:10:50 AKST
Magnitude 4.3, 98 miles SE of Chignik, August 5 10:00:17 AKST
Magnitude 4.3, 29 miles SE of Mt. Recheshnoi, August 29 00:30:16 AKST
Magnitude 4.3, 128 miles S of Akhiok, August 1 00:58:58 AKST

This report was compiled by N.Kozyreva

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 damaged resulting from its authroized or unauthorized use.

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