This polygon shapefile depicting relative landslide susceptibility from earthquakes was created using a simplified version of the methodology developed for San Mateo County, California by the USGS (Wieczorek and others, 1985). This approach is based on analysis of geologic and topographic data. Geologic units shown on sheets 1 and 2 were reclassified into three categories based on their assumed strength characteristics. The vector strength polygons were then converted into a raster grid with a 200-foot cell size. Slope inclination was derived from U.S. Geological Survey 30-m Digital Elevation Model files using ArcView Spatial Analyst software. The resultant values of geologic strength grid and the slope inclination were calculated for each cell and reclassified into the three categories as shown on the susceptibility matrix. Finally, the raster map was converted into a vector map. The resulting data set shows that the areas of highest susceptibility include Carmel Valley, the southern Big Sur coast, the Arroyo Seco district, and the foothills of the southern Salinas Valley. This layer is part of a collection describing Geology resources and constraints Monterey County, California. The purpose of this map is to provide a comparison of relative landslide hazards for regional planning studies in Monterey County. The focus of the map is large (hundreds to thousands of feet in length or width) deep-seated landslides caused by strong shaking. Shallow landslides such as debris flows and rock falls are strongly dependent on local site conditions and therefore are not included on this map. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.
