OF-18-06 Landslide Inventory and Susceptibility for Jefferson County, Colorado

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SKU: OF-18-06D Categories: , , , , , , , , Tags: , , , , , , , , , , , ,
Citation: Lindsey, Kassandra. “OF-18-06 Landslide Inventory and Susceptibility for Jefferson County, Colorado.” Landslide Analysis. Open File Report. Golden, CO: Colorado Geological Survey, October 2018.

Description

The CGS develops and provides geologic hazard susceptibility maps to state and local governments for use in planning processes and hazard mitigation plans. This map is part of a statewide effort to develop landslide inventory and susceptibility maps for landslide-prone areas in Colorado. Jefferson County is the fourth most populous county in Colorado. This study seeks to 1) evaluate and map known and previously unmapped landslide deposits with the aid of new high-resolution light detection and ranging (lidar) data and 2) identify landslide susceptible zones based on slope derived from a 10-m DEM and geology from geologic maps at various scales. Includes a report, a PDF map file, and GIS data. Digital ZIP download. OF-18-07D

From the Report:

The CGS provides geologic hazard susceptibility maps to state and local governments for use in planning processes and hazard mitigation plans. The Landslide Susceptibility Map of Jefferson County is part of a statewide effort to develop inventory and susceptibility maps for landslide-prone areas in Colorado. Jefferson County extends from the Rocky Flats area, north of Golden, to south of Buffalo Creek. It contains North Table Mountain, South Table Mountain, Green Mountain, and a section of the hogbacks. Much of the western part of the Denver Metro area lies within the county, as well as mountain towns like Evergreen, Conifer, and Pine. Extensive growth and development is taking place in Golden and the Rocky Flats region, where many landslides are located. This study reevaluates existing landslide boundaries with the aid of new high-resolution light detection and ranging (lidar) data and identify landslide susceptible zones based on slope derived from a 10-m DEM and geology from geologic maps at various scales.

A landslide is the failure and downslope movement of soil or rock due to the force of gravity exceeding the internal strength of the material. A distinct failure or rupture surface commonly forms below the failed mass on the surface where the weaker material moves downslope relative to the stronger, underlying material. Landslides may occur suddenly and move rapidly or slowly. All landslides have the potential to cause significant damage to structures. The type of material (for example rock, soil, or a mix) and failure movement mechanism (for example slide, flow, and fall) that provides nomenclature for the type of landslide. In this study, rockfalls, debris flows, and very slow-moving slumps and soil creep were not mapped.