Monthly Seismicity Report For October 1, 2019 to October 31, 2019

During the month of October 2019, the Alaska Earthquake Center reported 4,516 earthquakes within the state. The largest earthquake was magnitude 5.8 that occurred on October 25 at 16:41:22 AKST (October 26, 00:41:22 UTC), 37 miles S of Herbert Island. This was a busy month with 18 events felt, including a magnitude 4.5 earthquake 41 miles southeast of Cantwell which was strongly felt as far away as Anchorage. Other events of note include the magnitude 5 Offshore Kodiak aftershock on October 11th, and the magnitude 5.4 and 5.2 earthquakes in the Purcell Mountains on October 17th and 18th, which resulted in hundreds of aftershocks in the following days. The Eastern Brooks Range swarm and Kaktovik aftershocks are ongoing.

Notable Events in Descending Order of Magnitude

Magnitude 5.8, 37 miles S of Herbert Island, October 25 15:41:22 AKST
Magnitude 5.4, 24 miles NE of Attu, October 26 11:28:48 AKST
Magnitude 5.4, 41 miles S of Shungnak, October 17 15:58:28 AKST
Magnitude 5.2, 38 miles S of Shungnak, October 18 04:09:00 AKST
Magnitude 5.1, 39 miles N of Skwentna, October 4 03:28:02 AKST
Magnitude 5.0, 39 miles N of Skwentna, October 4 03:28:02 AKST
Magnitude 5.0, 181 miles SE of Kodiak, October 11 17:44:24 AKST
Magnitude 4.5, 41 miles SE of Cantwell, October 26 19:32:27 AKST
Magnitude 4.5, 5 miles W of Segula Peak, October 4 18:48:15 AKST
Magnitude 4.5, 5 miles W of Segula Peak, October 4 18:48:15 AKST

This report was compiled by M. Braun.

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.