M1.6 earthquake 16 km WSW of Unalaska, Alaska

A magnitude 1.6 earthquake struck 16 km WSW of Unalaska, Alaska on Tue, Jul 28, 2020, 10:10 PM AKDT (06:10 UTC), 7 km (4 mi) below the surface.

A larger quake followed: M3.6 68 km SE of Unalaska, Alaska. This one was a foreshock.

Map

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

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
1.6	ML, local (Richter)	Alaska Earthquake Center	Preferred · Preliminary
1.61	ML, local (Richter)	AV	Final · ±0.25591210101147 · 7 stations

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

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

Within 100 km, magnitude 1.5 and up: 72 in the 60 days after this one and 41 in the 30 days before it.

The first 60 of 72.

From the USGS Earthquake Hazards Program and its partner networks, event ak0209p210ek (also filed as av91105081). Read Fri, Oct 2, 2026, 5:15 AM UTC.