Non-Ergodic Scenario Maps for Performance Evaluation of Distributed Infrastructure

Session: Forthcoming Updates of the USGS NSHMs: Hawaii, Conterminous U.S. and Alaska [Poster]
Type: Poster
Date: 4/28/2020
Time: 08:00 AM
Room: Ballroom
Description: 

Evaluation of the seismic performance of distributed infrastructure requires estimates of the spatial dependence of earthquake ground motion from spatial correlation models of the ground motion. Previous spatial correlation models (e.g., Jayaram & Baker, 2009) use global datasets to develop correlation models that are ergodic and are then applied to ergodic ground motion models (GMMs). Because this approach uses an ergodic framework, it misses the repeatable spatial characteristics within the area of interest and the potential for local and regional correlation.

Rigorous calculation of risk for distributed infrastructure requires estimating ground motion spatially and including the performance assessment of the infrastructure inside the hazard integral. While the results are analytically correct, the fully probabilistic nature makes for complicated calculations and difficult explanations. As an alternative, a suite of scenario maps and associated probability of occurrence can be generated that approximates the seismic hazard of a region. Each of the scenarios represents a potential earthquake, which can be used in subsequent modeling efforts.

In this study, we develop the scenario maps using a non-ergodic framework, by using a non-ergodic GMMs model, which models the spatial dependence of the systematic source-, site- and path- parameters of the model, such as: distance attenuation, V_s30 scaling, basin scaling, etc. Because the non-ergodic GMMs model the spatial correlation of the local and regional systematic effects, they benefit by being informed by local ground motion recordings (or lack of recordings) and are tuned to a specific region. Together these features better define the ground motion associated earthquake scenarios.

For the results, we compare the scenario maps computed using ergodic and non-ergodic methods and outline a process for the development of a suite of scenario maps that approximates the seismic hazard in the San Francisco Bay Area.

Presenting Author: Albert R. Kottke

Authors