Landslide investigation of Timber Lakes Estates, Wasatch County, Utah: Landslide inventory and preliminary geotechnical-engineering slope stability analysis (MP 05-9)

By: D. P. Neuffer and R. L. Bruhn

We produced a comprehensive, detailed landslide map of Timber Lakes Estates in Wasatch County, Utah. Landslide deposits underlie about 13% of the total area of Timber Lakes (about 3,200 acres). We mapped twenty separate landslides scattered throughout Timber Lakes based on field observations and aerial photograph and topographic map interpretation. Ten of the landslides initiated as rotational rock slides or earth slides in the Tertiary Keetley Volcanics or Keetley-derived residual material and two of the ten have evolved into earth flows. The other ten landslides occur in Quaternary glacial till or derived colluvium. Seven of these ten slides are rotational earth slides and the remaining three are translational shallow debris slides. Three landslides, the Pine Ridge, Westview, and Aspen slides, display fresh scarps and other signs of recent activity. In addition, active debris sliding commonly occurs on slopes above Lake Creek. Six landslides, the Clyde Lake, Pine Ridge, Witts Lake, Tanglewood, Blazing Star, and Aspen slides, are being undercut by Lake Creek, threatening their stability. We also mapped lithologic contacts in the northwest portion of the study area and tabulated landslide and pertinent lithologic and hydrologic data obtained through field observations, measurements, and interpretations to help characterize the landslide hazard.

Other Information:
Published: 2005
Pages: 65 p.
Plates: 4 pl.
Scale: 1:24,000
Location: Wasatch County