The Hebgen Lake Earthquake Area, Montana and Wyoming

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Route

Start point

No route given

End point

No route given

Roads (and Trails)

US 191, Montana 287

Total distance

No route given

Geology

Summary

Several high-angle normal faults bounding the west front of the Madison Range north of Hebgen Lake, recurrently active during much of Neogene time, reactivated catastrophically on August 7, 1959. Faulting was accompanied by largest historic earthquake within the Intermountain Seismic Belt. Unusual geologic features were formed--spectacular fault scarps, a large landslide, a deformed lake basin (Hebgen Lake), and a new lake (Earthquake Lake)--each of which demonstrates the destructive power of a large eathquake. These features are described in the context of the bedrock geology in this field guide.

Key Lithologic Features

  • Precambrian gneiss, amphibolite, schist, and dolomite (part of the Cherry Creek metamorphic suite)
  • landslide debris

Structures

  • Red Canyon fault scarp
  • Hebgen Fault scarp
  • Madison Range fault scarp
  • deformed Hebgen Lake basin
  • Madison Slide

Landforms

  • Madison Range
  • fault scarps
  • Hebgen Lake
  • Earthquake Lake

Other Features

Reference

Witkind, I.J., and Stickney, M.C., 1987, The Hebgen Lake earthquake area, Montana and Wyoming, in Beus, S.S., ed., Centennial Field Guide Volume 2: Rocky Mountain Section of the Geological Society of America , p. 89-94.

Availability

Out of print. Check Amazon.com. Digital access to this publication is available via the links in the references section above.