CGS Seismic Hazards Program Update

The California Geologic Survey (CGS) Seismic Hazards Program has significantly updated two versions of its regulatory hazard zone map products. First, all GIS data files (in ESRI Shapefile format) for fault rupture, liquefaction and earthquake-induced landslide zones have been re-projected to California (Teale) Albers, in meters, with a North American Datum 1983. In addition, all GIS zone polygons now include attributes that provide the name of the 7.5-minute quadrangle, map release date(s), and links to zone reports and PDF maps. Active fault traces within earthquake fault zones have attributes for fault name and fault type.

A second significant upgrade has been made to PDF versions of zone maps in counties where there are overlapping fault rupture, liquefaction and earthquake-induced landslide zones, and where official zone maps have been prepared since 2012. These PDF maps allow users to turn layers on and off to create custom displays and, if a free toolbar is added to Acrobat Reader, allows users to read zone map attributes, as well as measure map coordinates and other geographic information.

The updated map products can be viewed and downloaded from the CGS Information Warehouse.  Information on how to obtain, install and use the free tool bar for Acrobat Reader can be found here.

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