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Sensitivities and Uncertainties in Probabilistic Fault Displacement Hazard Analysis in Southern California

Hong Kie Thio, & Jeff R. Bayless

Published August 15, 2018, SCEC Contribution #8734, 2018 SCEC Annual Meeting Poster #303

As applications of Probabilistic Fault Displacement Hazard Analysis (PFDHA) become more prevalent in California, it is of interest to understand the sensitivities and uncertainties in the models used, both for the source characterization as well as the empirical displacement prediction equations. In California, UCERF3 is the standard recurrence model for seismic hazard applications. In order to explore the effect of epistemic uncertainties on the uncertainties in the final hazard results we have used the full logic tree of UCERF3 in a PFHDA for a generic sites on the Newport-Inglewood strike-slip fault. For the displacement equations, we used the six relations from the Petersen et al. (2011) study, which is specifically geared towards strike-slip faults as well as the Takao et al. (2014) relations for all mechanisms for Japanese earthquakes.

The UCERF3 logic tree comprises of 2 geometrical alternatives (UCERF3.1 and UCERF3.2) each with 720 branches. Additional branches are 8 for the displacement relations and 2 more for alternative models for the probability of surface rupture. We will present the hazard results as maps of the hazard for an area around the fault, mean and fractile hazard curves to illustrate the range of uncertainty and tornado plots, which demonstrate the sensitivity of the final results to specific branches of the logic tree.

Thio, H., & Bayless, J. R. (2018, 08). Sensitivities and Uncertainties in Probabilistic Fault Displacement Hazard Analysis in Southern California. Poster Presentation at 2018 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Engineering Implementation Interface (EEII)