M2.5 earthquake 21 km N of Halfway, Oregon

A magnitude 2.5 earthquake struck 21 km N of Halfway, Oregon on Sun, Aug 20, 2017, 9:07 AM PDT (16:07 UTC), 1 km (1 mi) below the surface.

A larger quake followed: M3.0 22 km N of Halfway, 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
2.49	ML, local (Richter)	Pacific Northwest Seismic Network	Preferred · Final · ±0.207 · 6 stations
2.5	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed · ±0.207 · 6 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: 5 in the 60 days after this one and 3 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event uw61296192 (also filed as us2000a9y1). Read Sat, Oct 3, 2026, 7:54 AM UTC.