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Sigma-2: Improving the Reliability of Seismic Hazard Assessment for Critical Facilities

Session: Seismic Hazard Analysis for Critical Infrastructure

Type: Oral

Date: 4/19/2021

Presentation Time: 09:45 AM Pacific

Description: 

SIGMA-2 is a research program on Seismic Hazard Assessment (SHA). It coordinate efforts at the international level to improve the reliability and the accuracy of seismic hazard studies for industrial critical facilities. This program is funded by a consortium of 7 industrial partners involved in the nuclear energy sector (EDF, CEA, PG&E, SWISSNUCLEAR, ORANO, CEZ & CRIEPI), and supports more than 50 research actions conducted by academic and private scientific partners.

Current local and international regulations require that the design of critical infrastructures prove its resilience up to very-low-probability seismic hazard levels. Given the importance of safety and financial stakes associated with such critical facilities, a particular effort is needed to make such site-specific seismic hazard analysis realistic, adapted to local site conditions, and devoid of over-conservatism.

In this presentation, we present an overview of SIGMA-2 scope and research results of interest for the seismic hazard assessment of critical infrastructures. First, we summarize advances in site-response characterization and in the numerical simulation of site-effects. Then, we present ground-motion models for reference rock (i.e. unamplified) conditions, involving, among others, generalized inversion technique, and partially- or fully-non-ergodic approaches. New strategies for estimating and propagating epistemic uncertainties in the PSHA calculation have also been investigated, with applications to the maximum magnitude, to seismic rate parameters, and to GMMs. Finally, we discuss methods and current applications on the objective evaluation of PSHA results (and input models), with respect to observations. Using the principles of Bayesian inference, we illustrate how the confrontation of seismic/geophysical observations (e.g. instrumental records, macroseismic intensities, GPS measurements, earthquake catalogues) shed light on the importance of input model contributors on probabilistic SHA results.

Data, models and results are in open-access, and available at www.sigma-2net.

Presenting Author: Guillaume DANIEL

Student Presenter: No

Authors