← Back to Sessions

Impact of CyberShake on Risk Assessments for Distributed Infrastructure Systems

Session: Physics-Based Earthquake Rupture Modeling and Strong Motion Simulations [Poster]

Type: Poster

Date: 4/22/2021

Presentation Time: 03:45 PM Pacific

Description: 

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.

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.

For this work, we build on a recent probabilistic seismic risk analysis (PSRA) 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 based on a large set of events sampled from the UCERF3 model. The study utilized the NGA-West2 GMMs to compute ground motions with a level of spatial correlation that is consistent with empirical geostatistic models developed from global earthquakes. By repeating our study using the events and simulations from CyberShake, we are exploring the impact of region-specific simulations on seismic risk assessments of distributed infrastructure. This work will serve as a proof-of-concept and is expected to provide guidance to the research and PSRA user communities.

Presenting Author: Yajie Lee

Student Presenter: No

Authors