Historic Earthquakes
Hebgen Lake, Montana
1959 08 18 06:37:15 UTC (local 08/17)
Magnitude 7.3
Intensity X
Largest Earthquake in Montana
Damage Photos
Fault scarp and moat at Cabin Creek.
Gallatin County, Montana. 1959.
Red Canyon fault scarp near Red Canton Creek.
Man present in picture. Nineteen foot displacement measured.
Man for scale. Gallatin County, Montana. August 1959.
Sand spout (Sand Volcano) at Parade Rest Ranch.
At the time of the earthquake small fractures opened
in the ground, and water and sand spewed out. During
the earthquake, the tremors compacted the sand and gravel
fill, and ground water which occupied the pores and
interstices, was put under great pressure. As cracks
formed in the sand and gravel normal to earthquake wave
motion of repeated compression and expansion, water and
sand were forced out through the cracks.
Gallatin County, Montana. August 1959.
Landslide-broken road. Hebgen lake. Gallatin County, Montana.
August 1959.
The Red Canyon fault scarp where it cuts through
Blarneystone Rance. House sits on down thrown block;
fault scarp here is 10 to 12 feet high. A small collasped
shed (green roof) is on the up-thrown block.
Gallatin County, Montana.
The north end of Earthquake Lake. The trees to a level of
about 50 feet above the present surface of Earthquake
lake were once inundated for about 30 days while the Corps
of Engineers constructed a new spillway across the Madison
slide. The water was then let down to its present level.
During this time the trees below the water level died and
the water mark is clearly visible as a dark gray line.
Montana. August 1959.
Small longitudinal step fault scarps formed along the trace
of Hebgen fault. View is northward, and these small step
faults are along the south flank of Mount Hebgen, about
half a mile northeast of Hebgen Dam. All scarps are in
colluvium. Gallatin County, Montana. August 1959.
Earthquake Lake showing both its present level, and its
former level marked by a zone of dead needles. Partly
submerged house still shows in center. Montana. August 1959.
Photos from the Earth Science Photographs from the U.S. Geological Survey Library, by Joseph K. McGregor and Carl Abston, U.S. Geological Survey Digital Data Series DDS-21, 1995.
