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Home / Earthquakes / Montana

Montana Earthquake History

Since May 16, 1909, the USGS has recorded 58 earthquakes of magnitude 4.5 or greater in Montana, 5 of them magnitude 6 or above. The strongest was M 7.2.

By decade

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Strongest in Montana

M 7.2 · The 1959 Hebgen Lake, Montana EarthquakeAugust 18, 1959M 6.6 · The 1925 Clarkston Valley, Montana EarthquakeJune 28, 1925M 6.4 · Clarkston Valley, Montana (Aftershock)June 28, 1925M 6.1 · 12 km N of Winston, MontanaOctober 19, 1935M 6.1 · 30 km SSW of Big Sky, MontanaNovember 23, 1947M 6.0 · 21 km E of West Yellowstone, MontanaAugust 19, 1959M 5.9 · 6 km E of Montana City, MontanaOctober 31, 1935M 5.9 · 2 km ENE of Helena, MontanaOctober 12, 1935M 5.8 · 11 km SE of Lincoln, MontanaJuly 6, 2017M 5.6 · 16 km N of Dillon, MontanaJuly 26, 2005

All recorded earthquakes

M 6.0 mwAugust 19, 1959
21 km E of West Yellowstone, Montana · depth 5 km
M 7.2 mwAugust 18, 1959
The 1959 Hebgen Lake, Montana Earthquake · depth 12 km
M 5.5 faApril 1, 1952
Western Montana
M 6.1 mwNovember 23, 1947
30 km SSW of Big Sky, Montana · depth 15 km
M 5.0 mlNovember 28, 1935
2 km ENE of Helena, Montana
M 5.9 mwOctober 31, 1935
6 km E of Montana City, Montana · depth 10 km
M 6.1 mwOctober 19, 1935
12 km N of Winston, Montana · depth 15 km
M 5.9 faOctober 12, 1935
2 km ENE of Helena, Montana · depth 5 km
M 4.7 mfaFebruary 16, 1929
Northeast of Three Forks, Montana
M 4.9 mlFebruary 29, 1928
4 km NNW of Clancy, Montana
M 5.4 mfaDecember 13, 1926
Clarkston Valley, Montana (Aftershock)
M 5.5 mfaJuly 10, 1925
Clarkston Valley, Montana (Aftershock)
M 5.5 mfaJune 28, 1925
Clarkston Valley, Montana (Aftershock)
M 5.5 mfaJune 28, 1925
Clarkston Valley, Montana (Aftershock)
M 6.4 mfaJune 28, 1925
Clarkston Valley, Montana (Aftershock)
M 6.6 mwJune 28, 1925
The 1925 Clarkston Valley, Montana Earthquake
M 5.4 ukApril 19, 1910
Near Butte, Montana
M 5.4 mintMay 16, 1909
Northeastern Montana

Source: U.S. Geological Survey, Earthquake Hazards Program. Older and smaller earthquakes are under-counted relative to recent decades as instrumentation improved. A record of past shaking is not a forecast. See About the Data.