SCEC Award Number 14139 View PDF
Proposal Category Collaborative Proposal (Integration and Theory)
Proposal Title Retrospective CSEP Evaluation of Earthquake Forecasts during the 2010 Darfield Earthquake Sequence
Investigator(s)
Name Organization
Warner Marzocchi Istituto Nazionale di Geofisica e Vulcanologia (Italy) Maximilian Werner Princeton University Matthew Gerstenberger GNS Science (New Zealand) Maria Liukis University of Southern California
Other Participants
SCEC Priorities 2b, 2e, 2d SCEC Groups CSEP, EFP, WGCEP
Report Due Date 03/15/2015 Date Report Submitted N/A
Project Abstract
 The M7.1 Darfield earthquake triggered a complex earthquake cascade that provides a wealth of new scientific data to study earthquake triggering and evaluate the predictive skill of short-term earthquake forecasting models. To provide maximally objective results, a global CSEP collaboration of scientists from the US, New Zealand and Europe conducted a retrospective evaluation of short-term forecasting models during this sequence. Our primary objective was to assess the performance of newly developed physics-based Coulomb/rate-state seismicity models and hybrid statistical/Coulomb models against observations and against extant Omori-Utsu clustering models such as the Epidemic-Type Aftershock Sequence (ETAS) model. In stark contrast to previous CSEP results, we observed that Coulomb/rate-state models and hybrid Coulomb/statistical models provided more informative forecasts during the sequence than statistical models over all tested forecast horizons (1-year, 1-month and 1-day). We also evaluated the effect of near-real-time data on the quality of the forecasts by using daily real-time catalog snapshots obtained by the CSEP New Zealand testing center during the sequence. Surprisingly, forecasts do not universally degrade in quality when real-time data is used as input; results are model-dependent.
Intellectual Merit Our results document that newly developed Coulomb/rate-state forecasting models, which propagate epistemic uncertainties in input parameters and model choices into forecasts, can outperform statistical ETAS forecasts in rigorous and objective retrospective comparisons. These results provide support for the Coulomb/rate-state earthquake triggering hypothesis and may eventually guide the model development for Operational Earthquake Forecasting (OEF) systems.
Broader Impacts CSEP is a global initiative that relies on communication, open data exchange and collaboration. This project brought together experienced CSEP scientists and young doctoral modelers from the US, Europe and New Zealand. As a result, CSEP has increased its share of physics-based models under evaluation and has increased its visibility as an effective research tool to study the predictability of earthquakes.
Exemplary Figure Figure 3: Information gains of 1-year forecasts issued right after the 2010 Darfield earthquake and updated once in September 2011. Physics-based Coulomb/rate-state models are outperforming statistical models, including various ETAS models. Black: retrospective mode using best available data as model input. Red: pseudo-prospective mode using near-real-time data as model input.