Montana earthquakes

M4.9 earthquake 32 km SSE of Mammoth, Wyoming

A magnitude 4.9 earthquake struck 32 km SSE of Mammoth, Wyoming on Mon, Jun 30, 1975, 2:20 PM MDT (20:20 UTC), 5 km (3 mi) below the surface.

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Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude
4.9 (mb), light
Local time
UTC
1975-06-30 20:20:56 UTC
Depth
5.0 km (3.1 mi), shallow
Epicenter
44.692° N, 110.586° 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.

How well it is located

Reviewed by a seismologist.

Depth from
OPERATOR_ASSIGNED
Stations used
25

Nearest places

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

Nearby

Within 100 km, magnitude 1.9 and up: 12 in the 60 days after this one and 6 in the 30 days before it.

After

Before

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event usp0000buk (also filed as ushis3350). Read Tue, Sep 22, 2026, 8:54 PM UTC.