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
Southeastward view of the source area of the Madison Slide.
This view shows several of the unbroken dolomite remnants.
It was dolomite buttresses comparable to these which broke
and resulted in the slide. August 1959.
General view of the sand spouts (Sand Volcano) that
were formed near the Parade Rest Ranch. Wooded patch
in the background marks the course of Grayling Creek.
Gallatin County, Montana. August 1959.
Overal view of the Madison River slide from Earthquake Lake side.
The main mass of the slide covered by trees and soil is in the center
of the photograph. The dolomite debris that acted as the leading edge
of the slide is in the right center. The source area of the slide is in
the upper left corner, with the steeply dipping schist beds showing
along the ridge line. Madison County, Montana. August 1959.
Seiche marks on the walls of a unit at Hilgard
Lodge. These water marks indicate the height
and number of waves which passed this
particular site. Gallatin County, Montana. August 1959.
Oblique aerial view of Madison Canyon landslide from over Earthquake
Lake somewhat east of drowned toe of slide. Photograph was taken
after preparation of spillway had begun. Madison County, Montana. 1959.
Aerial view of Madison Canyon slide with Earthquake Lake in
background. Hebgen fault crosses dark forested spur near head
of lake. Madison County, Montana. August 1959.
One of the large cracks in the concrete retaining wall of Hebgen Dam.
The retaining wall, which is about 16 inches thick at the top and
about 27 inches thick at the base, has a great many cracks in it of
which 3 or 4 were as large as this one. The retaining wall slumped,
tilted forward, and was fractured during the earthquake; water seeped
through these fractures. Gallatin County, 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.
