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Digital geologic map and map database of parts of Marin, SanFrancisco, Alameda, Contra Costa, and Sonoma Counties, California


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2013-05-16 14:06:34


This digital map database, compiled from previously published andunpublished data, and new mapping by the authors, represents thegeneral distribution of bedrock and surficial deposits in the mapped area.Together with the accompanying text file (mageo.txt, mageo.pdf,, it provides current information on the geologic structure andstratigraphy of the area covered. The database delineates map units thatare identified by general age and lithology following the stratigraphicnomenclature of the U.S. Geological Survey. The scale of the source mapslimits the spatial resolution (scale) of the database to 1:62,500 orsmaller.


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This database and accompanying plot files depict the distribution ofgeologic materials and structures at a regional (1:62,500) scale. Thereport is intended to provide geologic information for the regional studyof materials properties, earthquake shaking, landslide potential,mineral hazards, seismic velocity, and earthquake faults. In addition,the report contains new information and interpretations about theregional geologic history and framework. However, the regional scaleof this report does not provide sufficientdetail for site development purposes. In addition, this map does nottake the place of fault-rupture hazard zones designated by theCalifornia State Geologist (Hart and Bryant, 1997). Similarly, thedatabase cannot be used to identify or delineate landslides in the region.

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