Impacts of CyberShake on Risk Assessments for Distributed Infrastructure Systems

Yajie Lee, Christine A. Goulet, ZhengHui Hu, Kevin R. Milner, & Scott Callaghan

Published March 23, 2021, SCEC Contribution #11724

In characterizing the system-level seismic risk of a spatially-distributed infrastructure network, empirical ground motion models (GMMs) are typically used to quantify the spatially correlated ground motion hazard. One current weakness of such empirical GMMs is that they are typically developed from global datasets representing “average” source, path attenuation, and site response characteristics of global earthquakes, and are associated with large variability reflecting a variety of crustal structures and conditions. Such differences in median and variability for a specific region can lead to poorly centered and wider than necessary distributions of the risk metrics.
As a solution to this limitation, the Southern California Earthquake Center CyberShake platform, designed as the first physics-based seismic hazard model to address the need for regional assessment of ground motions, simulates over 400,000 earthquake ruptures and propagates waves through 3D velocity models. Provided that the simulations have been properly validated, they should, in theory, include the source, path and site effects of a specific region.
We build on a recent GMM-based probabilistic seismic risk study of the entire underground water pipeline network for the City of Los Angeles, where the system-level risk - measured by the expected number of pipeline repairs, repair time, and repair cost - was established as a function of exceedance probability from a large set of earthquake simulations using the UCERF3 source model and the NGA-West2 GMMs. We repeat our study using the events and simulations from CyberShake and explore the impact of region-specific simulations on seismic risk assessments of distributed infrastructure.

Lee, Y., Goulet, C. A., Hu, Z., Milner, K. R., & Callaghan, S. (2021, 03). Impacts of CyberShake on Risk Assessments for Distributed Infrastructure Systems. Poster Presentation at 2021 EERI Annual Meeting.

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