Montana earthquakes

M2.7 earthquake 17 km SSE of Harrison, Montana

A magnitude 2.7 earthquake struck 17 km SSE of Harrison, Montana on Wed, Jul 22, 1987, 9:49 AM MDT (15:49 UTC), 4 km (3 mi) below the surface.

A larger quake followed: M3.2 16 km SSE of Harrison, Montana. This one was a foreshock.

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The earthquake

Magnitude
2.7 (ml), micro
Local time
UTC
1987-07-22 15:49:50 UTC
Depth
4.3 km (2.7 mi), shallow
Epicenter
45.555° N, 111.692° W
Region
Montana
Tsunami flag
No
Status
Reviewed by a seismologist

Did you feel it?

No one has reported feeling this quake to the USGS.

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 24 in the 60 days after this one and 20 in the 30 days before it.

After

Before

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event usp00036vf. Read Tue, Sep 22, 2026, 12:17 PM UTC.