M3.6 earthquake 92 km SSW of Adak, Alaska

A magnitude 3.6 earthquake struck 92 km SSW of Adak, Alaska on Mon, May 18, 2020, 2:28 AM HADT (11:28 UTC), 35 km (22 mi) below the surface.

A larger quake followed: M4.0 122 km WSW of Adak, 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
3.6	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.109 · 21 stations
2.9	ML, local (Richter)	Alaska Earthquake Center	Preliminary

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

Within 100 km, magnitude 1.5 and up: 179 in the 60 days after this one and 121 in the 30 days before it.

The first 60 of 179.

From the USGS Earthquake Hazards Program and its partner networks, event us70009mmq (also filed as ak0206e2f3wn). Read Fri, Oct 2, 2026, 7:06 PM UTC.