Earthquake Hazards Program

Prepared in cooperation with the
California Geological Survey
and the
Southern California Earthquake Center

USGS Open File Report 2007-1437
CGS Special Report 203
SCEC Contribution #1138
Version 1.1

The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2)

By 2007 Working Group on California Earthquake Probabilities*


*Edward H. Field, Timothy E. Dawson, Karen R. Felzer, Arthur D. Frankel, Vipin Gupta, Thomas H. Jordan, Tom Parsons, Mark D. Petersen, Ross S. Stein, Ray J. Weldon II, and Chris J. Wills

two maps of California

California’s 35 million people live among some of the most active earthquake faults in the United States. Public safety demands credible assessments of the earthquake hazard to maintain appropriate building codes for safe construction and earthquake insurance for loss protection. Seismic hazard analysis begins with an earthquake rupture forecast—a model of probabilities that earthquakes of specified magnitudes, locations, and faulting types will occur during a specified time interval. This report describes a new earthquake rupture forecast for California developed by the 2007 Working Group on California Earthquake Probabilities (WGCEP 2007).

Main Text

Download the main text of this 104-page report (of2007-1437_text.pdf; 11.5 MB).

Download just the Executive Summary as a 7-page report (of2007-1437_summary.pdf; 0.7 MB).

Download a supplemental Excel workbook. This workbook contains supplementary materials in 13 spreadsheets (of2007-1437_data.xls; 330 kB):


Appendix A: California Fault Parameters for the National Seismic Hazard Maps and Working Group on California Earthquake Probabilities 2007, by C.J. Wills, R.J. Weldon II, and W.A. Bryant

Appendix B: Recurrence Interval and Event Age Data for Type A Faults, by T.E. Dawson, R.J. Weldon II, and G.P. Biasi

Appendix C: Monte Carlo Method for Determining Earthquake Recurrence Parameters from Short Paleoseismic Catalogs: Example Calculations for California, by T. Parsons

Appendix D: Magnitude-Area Relationships, by R.S. Stein

Appendix E: Overview of the Southern San Andreas Fault Model, by R.J. Weldon II, G.P. Biasi, C.J. Wills, and T.E. Dawson

Appendix F: Summary of Geologic Data and Developments of A-Priori Rupture Models for the Elsinore, San Jacinto, and Garlock Faults, by T.E. Dawson, T.K. Rockwell, R.J. Weldon II, and C.J. Wills

Appendix G: Development of Final A-Fault Rupture Models for WGCEP/NSHMP Earthquake Rate Model 2.3, by E.H. Field, R.J. Weldon II, V. Gupta, T. Parsons, W.J. Wills, T.E. Dawson, R.S. Stein, and M.D. Petersen

Appendix H: WGCEP Historical California Earthquake Catalog, by K.R. Felzer and T. Cao

Appendix I: Calculating California Seismicity Rates, by K.R. Felzer

Appendix J: Spatial Seismicity Rates and Maximum Magnitudes for Background, by M.D. Petersen, C.S. Mueller, A.D. Frankel, and Y. Zeng

Appendix K: A-Priori Rupture Models for Northern California Type-A Faults, by C.J. Wills, R.J. Weldon II, and E.H. Field

Appendix L: Cascadia Subduction Zone, by A.D. Frankel and M.D. Petersen

Appendix M: Empirical Estimation of Regional Time Variation in Seismicity, by K.R. Felzer

Appendix N: Conditional, Time-Dependent Probabilities for Segmented Type-A Faults in the WGCEP UCERF 2, by E.H. Field and V. Gupta

Appendix O: Paleoseismic Investigations of the Walnut Site on the San Jacinto Fault, by T.E. Fumal and K.J. Kendrick (three large sheets)

Appendix P: Compilation of Surface Creep on California Faults and Comparison of WGCEP 2007 Deformation Model to Pacific-North America Plate Motion, by B.A. Wisely, D.A. Schmidt, and R.J. Weldon II

For questions about the content of this report, contact Ned Field

Suggested citation and version history

Also of Interest

USGS Fact Sheet 2008-3027 Forecasting California’s Earthquakes—What Can We Expect in the Next 30 Years? by Edward H. Field, Kevin R. Milner, and the 2007 Working Group on California Earthquake Probabilities

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