Historic Earthquakes

Southwest Montana
1947 11 23 09:46 UTC
Magnitude 6.3
Intensity VIII

Chimneys fell, twisted, or cracked in several towns in Madison County, including Alder, Cameron, Ennis, Laurin, and Virginia City. New springs formed in several areas, and creeks became muddy. Huge rocks rolled down the mountainside. Brick, masonry, and concrete structures sustained much damage. Also felt in parts of Idaho, Washington, and Wyoming.

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.