Alaska earthquakes

M3.8 earthquake 63 km W of Nanwalek, Alaska

A magnitude 3.8 earthquake struck 63 km W of Nanwalek, Alaska on Sat, Aug 22, 2020, 6:12 PM AKDT (02:12 UTC), 90 km (56 mi) below the surface.

A larger quake followed: M3.9 59 km SSE of Kokhanok, Alaska. This one was a foreshock.

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Map

Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude: 3.8 (ML, local (Richter)), minor
Magnitude from: Alaska Earthquake Center
Local time: Sat, Aug 22, 2020, 6:12 PM AKDT
UTC: 2020-08-23 02:12:08 UTC
Depth: 90.4 km (56.2 mi), intermediate-depth
Epicenter: 59.323° N, 153.040° W
Region: Alaska
Felt reports: 2
Tsunami flag: Yes: a large quake in an oceanic region
Status: Reviewed by a seismologist

Magnitude estimates

Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.

Mag.	Scale	Computed by	Notes
3.8	ML, local (Richter)	Alaska Earthquake Center	Preferred · Preliminary
4.2	mb, body-wave	USGS National Earthquake Information Center	Reviewed · ±0.121 · 19 stations
4.0	ML, local (Richter)	NOAA National Tsunami Warning Center	Reviewed · 23 stations

Tsunami

The USGS flags a quake this large in an oceanic region. The flag does not mean a tsunami happened; the tsunami warning centers decide that, and their messages are below when they issued any.

Current tsunami warnings: tsunami.gov. Warnings in force in the US also appear on our alerts pages.

Did you feel it?

2 people reported to the USGS what they felt; the strongest reported shaking was II, weak shaking.

How well it is located

Reviewed by a seismologist.

Stations used: 247

Nearest places

Distance and direction from each place to the epicenter, with its forecast.

Nearby

Within 100 km, magnitude 1.5 and up: at least 199 in the 60 days after this one and 120 in the 30 days before it.

After

The first 60 of at least 199.

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event ak020auc3cwc (also filed as at00qfhvg7, us6000bj9x). Read Sun, Oct 4, 2026, 8:58 PM UTC.