The California Geological Survey (CGS) has developed highway corridor landslide hazard maps to meet the needs of engineers, geologists, planners, and maintenance staff of the California Department of Transportation (Caltrans). The project was initiated after the 1997 Mill Creek Slide closed a portion of U.S. Highway 50 for approximately one month. Maps prepared by CGS as part of the emergency response and recovery from the 1997 incident now serve as a planning and maintenance document for developing long-term mitigation strategies. Recognizing the value of this product, Caltrans contracted with CGS to develop a series of maps of selected California highway corridors within a variety of climatological and geological settings. The maps provide an inventory of landslide activity along the selected highway corridors. This “big picture” perspective will benefit planning of route improvements and lead to more effective landslide risk mitigation for California's highways.
Each of the reports prepared under this project includes a description of the geologic materials along the highway corridor, the distribution and types of landslides, and the potential impacts of landslides on the highway. Geologic and landslide inventory maps are included in each report. In most reports, Plate 1 (the geologic map) and Plate 2 (the landslide map) are formatted into map sections that can be downloaded and printed on 11x 17 inch size pages.
Special Report 185 - Landslides in the Highway 1 Corridor: Geology and Slope Stability along the Big Sur Coast between Point Lobos and San Carpoforo Creek, Monterey and San Luis Obispo Counties, California
by C.J. Wills, M.W. Manson, K.D. Brown, C.W. Davenport and C.J. Domrose, 2001, California Geological Survey, 40 pgs.
Download Special Report 185 (1.1 MB)
Special Report 186 - Landslides in the Highway 60 Corridor San Timoteo Badlands Riverside County, California
by M.W. Manson, C.W. Davenport, K.D. Brown, C.J. Wills, and C.J. Domrose, 2002, California Geological Survey, 21 pgs.
Download Special Report 186 (1.4 MB)
Special Report 187 - Landslides in the Highway 101 Corridor between Leggett and Piercy, Mendocino County, California
by M.W. Manson, C.W. Davenport, C.J. Domrose and C.J. Wills, 2003, California Geological Survey, 32 pgs.
Download Special Report 187 (3.3 MB)
Special Report 188 - Landslides in the Interstate 5 Corridor between Valencia and Gorman, Los Angeles County, California
by B.D. Foster, 2003, California Geological Survey, 23 pgs.
Download Special Report 188 (1 MB)
Special Report 195 - Landslides in the Highway 299 Corridor Between Blue Lake and Willow Creek, Humboldt County, California
by J.N. Falls, C.J. Wills and B.C. Hardin, 2006, California Geological Survey, 59 pgs
Download Special Report 195 (3.5 MB)
Special Report 196 - Landslides in the Highway 1 Corridor between Bodega Bay and Fort Ross, Sonoma County, California
by M.W. Manson, C.M. Huyette, C.J. Wills, M.E. Huffman, M.G. Smelser, M.E. Fuller, C. Domrose and C. Gutierrez, 2006, California Geological Survey, 26 pgs
Download Special Report 196 (1 MB)