M4.0 earthquake 135 km ESE of Nikolski, Alaska

A magnitude 4.0 earthquake struck 135 km ESE of Nikolski, Alaska on Mon, Sep 23, 2019, 10:04 AM AKDT (18:04 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M4.1 142 km ESE of Nikolski, 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
4.0	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.095 · 30 stations
3.5	ML, local (Richter)	Alaska Earthquake Center	Preliminary

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: 69 in the 60 days after this one and 33 in the 30 days before it.

The first 60 of 69.

From the USGS Earthquake Hazards Program and its partner networks, event us60005mbu (also filed as ak019c87p249). Read Fri, Oct 2, 2026, 6:33 PM UTC.