Historic Earthquakes

Clarkston Valley, Montana
1925 06 28 01:21 UTC (local 06/27)
Magnitude 6.6
Intensity VIII

Isoseismal Map

Isoseismals are based on intensity estimates from data.

Isoseismal Map

Abridged from Seismicity of the United States, 1568-1989 (Revised), by Carl W. Stover and Jerry L. Coffman, U.S. Geological Survey Professional Paper 1527, United States Government Printing Office, Washington: 1993.