Colorado Landslide Inventory
2011 landslide along West Mosquito Creek in Park County, Colorado.
Photo by Colorado Division of Reclamation Mining and Safety
The CGS is digitizing all mapped landslides that have been published in geologic and geologic hazard maps of Colorado. Landslides have been digitized as map polygons from four broad categories of geologic maps.
- The yellow polygons are landslides digitized from all published 1:24,000-scale (1 inch equals 2,000 feet) maps by CGS and USGS. These maps include standard geologic maps of 1:24,000-scale quadrangles and specific geologic hazard mapping that has been completed at the 1:24,000 scale in several areas of the state. This map scale, where features are larger, will have the best detail. The boundaries of the mapped 1:24,000-scale quadrangles are also shown in the map viewer.
- The olive-green polygons are landslide polygons digitized from smaller map scale 1:48,000 to 1:100,000 geologic maps. This collection of maps is only partially represented in the inventory at this time.
- The red polygons are landslide areas digitized from 1:250,000-scale USGS mapping in the mid 1970s by Colton and others on 1 degree by 2 degree quadrangles.
- The orange polygons are landslide and unstable slope areas digitized from all available geologic hazards mapping that was completed in the mid 1970s under the auspices of Colorado House Bill 1041. Most of this work was completed in a 1:24,000 scale.
In the Colorado landslide inventory map viewer, each polygon that represents a mapped landslide can be queried for the publication citation and the map unit. More than one scale of map exists in many areas of the state. In those areas, there are overlapping landslide polygons.
Basemaps on the map viewer include the grid of the 1:24,000-scale quadrangles, high resolution aerial photography from the Colorado 2009 National Agriculture Imagery Program (NAIP), and a hillshade developed from the USGS 10-m digital elevation model.
To view the CGS landslide inventory map viewer, click Here.
To download the four current coverages of the landslide inventory as ESRI shapefiles (.shp), click Here.
This landslide inventory only reflects the location of landslides digitized from existing maps prepared by many different authors. No original landslide mapping was completed for this inventory. This inventory also does not presently include landslides mapped by private consultants, or academic or professional publications outside of the CGS and USGS. The lack of a mapped landslide in a given area does not imply that landslide do not exist at or near that location, or the ground is inherently stable. This map viewer should be used by trained individuals using it in conjunction with geologic bedrock maps, an understanding of the shear strength of geologic formations, hydrologic conditions, and steepness of slope to recognize regional susceptibilities of slope instability. It should not be utilized in-lieu of site-specific investigations to identify the threat of landsliding, or slope-stability adequacy for a specific land usage.