Prepared under the authority of the Seismic Hazards Act of 1990, they are used by cities and counties to regulate development. A Seismic Hazard Mapping Program Factsheet more fully describes the program. The Index to Seismic Hazard Zone Maps contains links to .jpeg and more detailed .gif images of each map which are also available for purchase in full-scale print format. The alphabetized List of Available Seismic Hazard Mapping Program Products also links to available maps as well as accompanying evaluation reports and gis files. More detailed images available in clickable 45x45 degree squares.
Interactive site includes composite portraits of U.S. topography and geology.
The site provides maps and descriptions of rocks by geologic time, geologic maps for individual states, physiographic regions, and descriptions of unique geologic features. The Watersheds Mapping Project produced a series of 60 USGS 7.5 minute quadrangles between 1982 and 1985 that provided detailed information on the geology and geomorphic features affecting landsliding in sensitive watersheds in Mendocino, Humboldt, and Del Norte Counties of California. These maps are available in .pdf format.