USE OF REMOTE-SENSING TECHNOLOGY TO ENHANCE GEOLOGIC PRODUCTS OF THE CALIFORNIA GEOLOGICAL SURVEY USED FOR PUBLIC POLICY

Most technical products of the California Geological Survey (CGS) are intended for use in public policy, which can range from conservation of mineral resources to protection of citizens from earthquakes and hazardous minerals. To enhance its products, CGS is operationally using remote-sensing technology in three projects, with the goal that all of its technical programs will eventually use remote sensing routinely within their GIS functions. This integration is expected to improve the quality, timeliness, and cost of the products.

The first project involves use of satellite images to map encroachment of urbanization and other types of incompatible land use on aggregate deposits in the Palm Springs and Bakersfield areas. Supported by a grant from NASA under its Broad Agency Announcement Program, the project has demonstrated how such imagery can reduce fieldwork and supplement or substitute for traditional aerial photography in the process of mapping; the images have improved quantification of remaining aggregate resources in these communities.

The second project is part of our Seismic Hazards Mapping Program, which prepares maps that show areas potentially susceptible to landslides and liquefaction induced by earthquakes. Located in northern Los Angeles County, this study evaluated various sets of imagery, including ASTER and Landsat 7, for their utility in identifying or refining geologic contacts that represent boundaries for zones of landslides and liquefaction. These boundaries are important to landowners, to government officials who make land-use decisions, and for determining whether detailed geologic studies are required pending land development.

The last project, through use of an airborne imaging spectrometer (AVIRIS), seeks improved mapping of localities and lithologic units, particularly ultramafic rock and serpentinite, that contain or may contain naturally occurring asbestos minerals (e.g., chrysotile, tremolite). CGS and the U.S. Geological Survey are collaborating on analysis of AVIRIS data collected over potential asbestos-bearing rocks in El Dorado and Plumas counties. Asbestos minerals can be hazardous to human health, and refined mapping of them can alert government officials to locations that warrant special regulation or protection from physical disturbance.