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Strategies for building community-based geodetic models of fault slip rates

Eileen L. Evans

Published July 28, 2017, SCEC Contribution #7355, 2017 SCEC Annual Meeting Talk on Tue 13:30

Developing a comprehensive model of tectonic continental deformation requires assessing 1) fault slip rates, 2) off-fault deformation rates, and 3) realistic uncertainties. Fault slip rates can be estimated by modeling fault systems based on space geodetic measurements of active surface ground displacement, such as Global Navigation Satellite Systems (GNSS) and interferometric synthetic aperture radar (InSAR). However, geodetic slip rate estimates may vary widely due to measurement and epistemic (model) uncertainties, which poses a challenge for both estimating slip rates and accurately characterizing uncertainties. Furthermore, differing modeling assumptions may represent ongoing scientific disagreements (e.g., block models vs. distributed deformation) that should be captured in a community model. Taking an alternative yet complementary approach to the SCEC community geodetic model (CGM), which integrates geodetic data into a model of active deformation, I compile estimated fault slip rates from 33 published models in California to determine average geodetic slip rates and assess model uncertainties. Because geodetic slip rate models may vary in the number of faults represented and the precise location of those faults, I combine these models on a common georeferenced grid and calculate spatially averaged long-term deformation within each grid cell. Averaging over multiple published models produces a community-averaged long-term deformation model of California, and standard deviation provides a measure of model uncertainty. This approach enables holistic comparison with geologic slip rates, reveals gaps in model coverage, and provides insights into the role of model uncertainties in estimates of off-fault deformation.

Evans, E. L. (2017, 07). Strategies for building community-based geodetic models of fault slip rates. Oral Presentation at 2017 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy