Highway Corridor Landslide Hazard Mapping

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 184 - Landslides in the Highway 101 Corridor between Wilson Creek and Crescent City, Del Norte County, California

by C.J. Wills, 2000, California Geological Survey, 24 pgs.

Download Special Report 184 (1.8 MB)
Download Geologic Map (1 MB)
Download Landslide Map (2.2 MB)

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)

Download Geologic Maps 

Plate 1 Explanation

Map 1

Map 2

Map 3

Download Landslide Maps

Plate 2 Explanation

Map 1

Map 2

Map 3

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)

Download Geologic Maps 

Map 1

Map 2

Map 3

Map 4

Map 5

Map 6

Map 7

Download Landslide Maps

Map 1

Map 2

Map 3

Map 4

Map 5

Map 6

Map 7


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)

Download Geologic Maps

Sheet 1 - Western Portion (22 MB)

Sheet 2 - Eastern Portion (20 MB)

Download Landslide Maps

Sheet 1 - Western Portion (22 MB)

Sheet 2 - Eastern Portion (21 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)