Prospective and retrospective evaluation of five-year earthquake forecast models for California

Anne Strader, Max Schneider, Danijel Schorlemmer

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


The Collaboratory for the Study of Earthquake Predictability was developed to prospectively test earthquake forecasts through reproducible and transparent experiments within a controlled environment. From January 2006 to December 2010, the Regional Earthquake Likelihood Models (RELM) Working Group developed and evaluated thirteen time-invariant prospective earthquake mainshock forecasts. The number, spatial and magnitude components of the forecasts were compared to the observed seismicity distribution using a set of likelihood-based consistency tests. In this RELM experiment update, we assess the long-term forecasting potential of the RELM forecasts. Additionally, we evaluate RELM forecast performance against the Uniform California Earthquake Rupture Forecast (UCERF2) and the National Seismic Hazard Mapping Project (NSHMP) forecasts, which are used for seismic hazard analysis for California. To test each forecast's long-term stability, we also evaluate each forecast from January 2006 to December 2015, which contains both five-year testing periods, and the 40- year period from January 1967 to December 2006. Multiple RELM forecasts, which passed the N-test during the retrospective (January 2006 to December 2010) period, overestimate the number of events from January 2011 to December 2015, although their forecasted spatial distributions are consistent with observed earthquakes. Both the UCERF2 and NSHMP forecasts pass all consistency tests for the two five-year periods; however, they tend to underestimate the number of observed earthquakes over the 40-year testing period. The smoothed seismicity model HELMSTETTER-ET-AL.MAINSHOCK outperforms both United States Geological Survey (USGS) models during the second five-year experiment, and contains higher forecasted seismicity rates than the USGS models at multiple observed earthquake locations.
Original languageEnglish (US)
Pages (from-to)239-251
Number of pages13
JournalGeophysical Journal International
Issue number1
StatePublished - Jun 20 2017
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2022-06-03
Acknowledged KAUST grant number(s): URF/1/2160-01-01
Acknowledgements: This study was funded by the Global Earthquake Model (GEM) foundation, King Abdullah University of Science and Technology (KAUST) research grant URF/1/2160-01-01, and Deutscher Akademischer Austauschdienst (DAAD) grant 57130097. All data and testing infrastructure used in this experiment were provided by the CSEP California testing center in Los Angeles, and data for observed earthquakes were provided by the Advanced National Seismic System (ANSS).
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


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