SCEC Award Number 25342 View PDF
Proposal Category Community Workshop
Proposal Title CSEP Workshop: Physics-Based Earthquake Forecasting
Investigator(s)
Name Organization
Maximilian Werner University of Bristol (United Kingdom) Francesco Serafini University of Bristol (United Kingdom) Philip Maechling University of Southern California
SCEC Milestones D2-2, C1,2,3-1, D1-1 SCEC Groups EFP, Seismology, RC
Report Due Date 02/20/2026 Date Report Submitted 02/25/2026
Project Abstract
 We request funds for a one-day workshop before the SCEC annual meeting to stimulate the development and evaluation of physics-based earthquake forecasting along the entire San Andreas plate boundary system. Current operational forecasting systems around the globe employ empirical-statistical models, which encode seismicity clustering with simple empirical statistical distributions. While thoroughly tested and in some respects useful, these models struggle to provide higher predictive skills of moderate to large quakes, and they can also struggle with the range of seismicity patterns and fault slip observed in California, such as swarm behaviour in the Salton Trough and elsewhere, surficial and deep aseismic slip, or unexplained variability in aftershock productivity. In this workshop, we will challenge the reigning “one-size-fits-all” statistical model paradigm with physics-based modelling approaches and empirical studies that contradict standard models like the standard Epidemic Type Aftershock Sequence (ETAS) model. We will review CSEP benchmarks and tools that could be useful for back-testing and model development, as well as identify additional needs for more physics-based efforts. Types of physics-based models we envisage represented include large scale multi-cycle quasi-dynamic rupture simulators on fault networks (like RSQSim), smaller scale microphysical models, hybrid statistical-physical Coulomb/rate-and-state models like the Dieterich (1994) formulation, and those that incorporate slow slip or other data types.
Intellectual Merit The workshop contributes to SCEC’s goal of advancing the predictability of earth-quakes by rigorous testing of models and developing new and improved models. One example of innovation involves the development of new methods to evaluate simulation-based forecasting models.
Broader Impacts CSEP actively promotes open research principles amongst the community, includ-ing the publication of reproducibility packages and open-source community-developed software along with training workshops and online and in-person tutori-als. These efforts have broadened the participant base and elevated the field’s ri-gor. CSEP’s forecast model evaluations provide independent assessments of the kinds of models that international and US government agencies use for public fore-casting, thereby building objective confidence in their predictive skills and exposing limitations.
Project Participants The core CSEP group currently involves scientists from the University of Bristol, GFZ Potsdam, SCEC, ETH Zurich and GNS Science (now called Earth Sciences New Zealand). The planning workshop also included researchers from UCLA and the USGS. The workshop was attended by about 15 attendees, including M Werner, F Serafini, L Vazquez, A Gabriel, M Page, N Field, K Milner, T Jordan, A ELbanna, P Maechling, R Schoenberg and others.
Exemplary Figure Figure 1: Spatio-temporal evolution of a synthetic UCERF3-ETAS catalog with multiple finite ruptures for 5 April 2010, the day after the 2010 El Mayor Cucapah earthquake. Points with the same color have the same parent. The parent and offspring are color-coded to identify 4 generations. Point size is proportional to magnitude and triangles rep-resent finite ruptures [taken from Serafini et al., 2026, in preparation].
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