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U.S. Geological Survey Open-File Report 96–705, v. 1.1

Database of Potential Sources for Earthquakes Larger than Magnitude 6 in Northern California

By The Working Group on Northern California Earthquake Potential

Thumbnail of and link to report PDF (1.4 MB)Abstract

The Northern California Earthquake Potential (NCEP) working group, composed of many contributors and reviewers in industry, academia and government, has pooled its collective expertise and knowledge of regional tectonics to identify potential sources of large earthquakes in northern California. We have created a map and database of active faults, both surficial and buried, that forms the basis for the northern California portion of the national map of probabilistic seismic hazard. The database contains 62 potential sources, including fault segments and areally distributed zones. The working group has integrated constraints from broadly based plate tectonic and VLBI models with local geologic slip rates, geodetic strain rate, and microseismicity. Our earthquake source database derives from a scientific consensus that accounts for conflict in the diverse data. Our preliminary product, as described in this report brings to light many gaps in the data, including a need for better information on the proportion of deformation in fault systems that is aseismic.

Last modified May 23, 2012
First posted January 14, 2011

  • This report is available only on the Web.

For additional information:
Contact Information, Earthquake Science Center, Menlo Park Science Center
U.S. Geological Survey
345 Middlefield Road, MS 977
Menlo Park, California 94025

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Suggested citation:

Working Group on Northern California Earthquake Potential, 1996, revised 2012, Database of potential sources for earthquakes larger than magnitude 6 in northern California: U.S. Geological Survey Open-File Report 96–705, v. 1.1, 53 p. and GIS data. (Available at





Fault Zones





one appendix

GIS data

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