RECENT GEOLOGIC COMPILATIONS IN CALIFORNIA’S CENTRAL VALLEY BY THE CALIFORNIA GEOLOGICAL SURVEY AND THE DEVELOPMENT OF A NEW DIGITAL GEOLOGIC MAP OF CALIFORNIA

The California Geological Survey (CGS) has recently completed geologic compilations of the Sacramento, Lodi, and Stockton 30x60-minute quadrangles in the southern Sacramento Valley and northern San Joaquin Valley. This work was performed as part of the STATEMAP program, an ongoing cooperative effort with the USGS to produce geologic maps of 7.5-minute and 30x60-minute quadrangles in California. The area covered by these new maps includes a large portion of the Sacramento-San Joaquin River Delta, critical infrastructure related to flood control and the State Water Project, and several densely populated urban areas. The new maps, prepared by various authors, represent a digital compilation of the best available geologic mapping for the region, and provide a consistent geologic framework that can be utilized as a basis for the analysis of a host of concerns in California, including seismic hazards to infrastructure, environmental management, and groundwater issues.

CGS also plans to use the digital data developed for these maps as the foundation for building a new digital geologic map of California based on the most detailed geologic information available. Once established, digital geologic datasets developed for other STATEMAP and CGS products can be migrated into the new statewide digital geologic map. This new map and associated database will support CGS’s goals to bring new and existing map information into standardized data and cartographic formats, and to release the new maps for public use as downloadable images and GIS data, as well as for viewing on an interactive web-based Google Map platform.