M2.8 earthquake 37 km NNE of Amboy, Washington

A magnitude 2.8 earthquake struck 37 km NNE of Amboy, Washington on Mon, Sep 9, 1991, 5:17 PM PDT (00:17 UTC), 3 km (2 mi) below the surface.

A larger quake followed: M3.1 8 km ENE of North Plains, Oregon. 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
2.8	Md, duration	Pacific Northwest Seismic Network	Preferred · Final · ±0.03 · 32 stations
2.8	Md, duration	USGS National Earthquake Information Center	Reviewed

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: 39 in the 60 days after this one and 8 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event uw10276663 (also filed as usp0004wf7). Read Sat, Oct 3, 2026, 5:36 AM UTC.