An ensemble approach to tectonic block models: new capabilities and applications

Eileen L. Evans, Jayson P. Sellars, Abigail Travers, Monica A. Diaz, & Jack P. Loveless

Submitted September 7, 2025, SCEC Contribution #14712, 2025 SCEC Annual Meeting Poster #TBD

Determining fault slip rates throughout a complex fault system, such as in southern California, is essential for understanding tectonic strain partitioning at plate-boundary scales. Fault slip rates may be estimated using tectonic geomorphology and paleoseismology (geologic slip rates) or modeled from satellite geodetic measurements such as Global Navigation Satellite Systems (GNSS) (geodetic slip rates). Geodetic slip rates may be estimated within kinematic block models, in which the crust is divided into rigid microplates bounded by faults, and fault slip rates are determined by differential rotation rates at block boundaries. Because block models require that faults connect to form closed, rigid blocks, some model faults must be inferred or extrapolated from mapped structures, limiting interpretation of estimated slip rates. Recent advances in block modeling allow the creation and consideration of an ensemble of models for robust estimates of fault slip rate and model-based uncertainties. Here, we create an ensemble of block models of southern California tectonics constrained by GNSS observations to compare with geologic slip rates. Considering model ensembles may lead to better agreement between geologic and geodetic slip rates, suggesting that many slip rate discrepancies may be due to epistemic uncertainties in geodetic modeling assumptions such as fault geometry and model regularization.

Citation
Evans, E. L., Sellars, J. P., Travers, A., Diaz, M. A., & Loveless, J. P. (2025, 09). An ensemble approach to tectonic block models: new capabilities and applications. Poster Presentation at 2025 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy