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California Geological Survey - Digital Database of Quaternary and Younger Faults from the Fault Activity Map of California, Version 2.0  

Digital Database of Quaternary and Younger Faults from the Fault Activity Map of California, Version 2.0

The Fault Activity Map of California, compiled by C. W. Jennings at a scale of 1:750,000 and published in 1994, is the basic source for fault location and fault activity data in California.  Bulletin 201 and the explanatory text that accompanies the Fault Activity Map provide the detailed information on references used for fault location and activity.  The published map scale necessitates a generalized depiction of faults and limits fault location accuracy.  The California Geological Survey released a digital version of the Fault Activity Map in 2000 (CGS CD- 2000-06) that was attributed with only line type (solid, dashed, dotted) and fault age (Historic, Holocene, Late Quaternary, undifferentiated Quaternary, pre-Quaternary).  Fault traces were digitized from the 1:750,000 compilation, so the generalized depiction and location accuracy of the small scale remain.  While digital data can be reproduced precisely at any scale, the accuracy of the data remains constant.  As the scale is increased from 1:750,000, uncertainties and errors in fault location remain the same.

Version 2.0 of the digital fault activity map, Digital Database of Quaternary and Younger Faults from the Fault Activity Map of California, is an interim product that broadens the fault data attribution fields to include: fault name/fault zone name, sense of displacement, slip rate (binned category consistent with National Quaternary Fault and Fold database in mm/yr), fault id (Jennings numbering system, if applicable), Qt fault database id (and section # and section name, if applicable), fault age (same as version 1.0), line type (same as version 1.0), source of mapping, version number, and date current version was released.  About 85% of the Quaternary and younger faults have been attributed with most of the additional data fields in version 2.0.

This update is for Quaternary and younger faults only.  CGS, in a cooperative agreement with the U.S. Geological Survey, began preparing compilations and fault maps for the California portion of the National Quaternary Fault and Fold database (http://earthquake.usgs.gov/qfaults/).  The National Quaternary Fault and Fold database is a source for detailed information on faults and is the source of basic fault data used in the Probabilistic Seismic Hazards Assessment (http://www.consrv.ca.gov/CGS/rghm/psha/index.htm).  Version 2.0 of the digital Fault Activity Map was begun as part of this cooperative agreement. 

Most significant late Quaternary and younger faults are now better-portrayed digitally in version 2.0, both with respect to location and the depiction of complexity.  As work on the fault map progressed, it was decided to re-digitize fault trace locations using the original sources at the original source scale.  Version 2.0 represents the beginning phase of this task and about 25% of the faults have been re-digitized from the original sources.  Version 2.0 will be superceded by future updates and revisions.

Copies of version 2.0 of the Digital Database of Quaternary and Younger Faults from the Fault Activity Map of California are available for downloading in two file formats: ESRI ARC/INFO uncompressed export (e00) and MapInfo tab files.  Also included are state outline and county boundary files in ESRI e00 and MapInfo tab format and metadata files in html and text format.

Download GIS files here:
ESRI files in Qt_flt_v2-0_esri.zip (5.5 MB)
Qt_flt_v2-0.e00
county.e00
statemap.e00
Metadata files (html and text files)

MapInfo files in Qt_flt_v2-0_map.zip (2 MB)
Qt_flt_v2-0.tab
Qt_flt_v2-0_tic.tab
county_line.tab
county_line_tic.tab
statemap_line.tab
statemap_line-tic.tab
Metadata files (html and text files)

This web-based publication should be referenced as follows:

Bryant, W. A. (compiler), 2005, Digital Database of Quaternary and Younger Faults from the Fault Activity Map of California, version 2.0: California Geological Survey Web Page, <http://www.consrv.ca.gov/CGS/information/publications/QuaternaryFaults_ver2.htm>; (date downloaded from web site)