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Vision for Validation and Calibration of Physics-Based Ground Motion Simulation for Applications in California

Chukwuebuka C. Nweke, Sajan K C, Robert W. Graves, & Jonathan P. Stewart

Submitted September 10, 2023, SCEC Contribution #13296, 2023 SCEC Annual Meeting Poster #179

As described in Rezaeian et al. (Earthquake Spectra, in second review), SCEC research on ground motion validation has included multiple studies in which broadband simulations, generally from the Broadband platform, have been performed and compared to data from the simulated event or from semi-empirical ground motion models. These validations have revealed a variety of issues in simulated ground motions, including overall bias, distance attenuation misfit, and dispersion misfits. As SCEC enters a new funding cycle, we envision further developing this line of research to create feedback loops whereby misfits identified from validation lead to adjustments to the simulation models (or changes in their parameters), new simulated ground motions are provided, further validations are performed, and eventually compatibility is achieved. Such checks of simulation performance should consider (1) ground motion and dispersion levels for reference conditions (e.g., a certain range of distances for a particular magnitude), (2) scaling of ground motions with key predictor variables (magnitude, distance, site parameters, directivity, etc.), and (3) spatial variations of ground motion attributes across the California study region. The process described here has been undertaken elsewhere, for example in New Zealand (Lee et al. 2022, Earthquake Spectra), which provides motivation for how simulated ground motions, their validation, and their ultimate adoption can significantly advance during the coming years.

Nweke, C. C., K C, S., Graves, R. W., & Stewart, J. P. (2023, 09). Vision for Validation and Calibration of Physics-Based Ground Motion Simulation for Applications in California. Poster Presentation at 2023 SCEC Annual Meeting.

Related Projects & Working Groups
Ground Motions