Uncertainties in ground motion prediction in probabilistic seismic hazard analysis (PSHA) of civil infrastructure - Seismic Risk Analysis and Management of Civil Infrastructure Systems - page 27

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Uncertainties in ground motion prediction in
probabilistic seismic hazard analysis (PSHA)
of civil infrastructure

P. J. STAFFORD, Imperial College London, UK

DOI : 10.1533/9780857098986.1.29

Abstract : Ground-motion prediction equations are a critical element of
any probabilistic seismic hazard or risk analysis. The total uncertainty in
a typical risk analysis is commonly dominated by the uncertainty
associated with ground-motion prediction. Within the fi elds of
engineering seismology and earthquake engineering a lot of attention
has been paid to identifying intensity measures that are effi cient for
predicting response measures, and this effi ciency is of great relevance for
seismic risk analysis and the development of well-constrained fragility
curves. However, the epistemic uncertainties associated with ground
motions are still not adequately dealt with, and such uncertainties
contribute to the overall predictability of an intensity measure, and
hence of an engineering demand parameter. The present chapter
provides an overview of the uncertainties that exist within ground-
motion prediction and emphasises some of the main components that
are not dealt with in a robust manner in current risk analyses. The
chapter also highlights recent advancements as well as likely future
trends associated with the treatment of uncertainty in ground-motion
prediction, with a particular emphasis upon how such uncertainties
infl uence the development of ground-motion models.

Key words : ground-motion prediction equation (GMPE), probabilistic
seismic hazard analysis (PSHA), aleatory variability, epistemic
uncertainty, parametric, ergogic assumption, input variable uncertainty.

2.1 Introduction

Engineering seismology is a discipline of fundamental importance to earth-
quake risk analysis. The primary focus of an engineering seismologist is to
develop models that provide a characterisation of earthquake-induced
ground shaking that is of use as an input for structural analysis. More spe-
cifi cally, an engineering seismologist would most likely view their role as
involving the development and application of empirical ground-motion
models, as well as the undertaking of probabilistic seismic hazard analyses.
The outputs of the latter are used as inputs for site-specifi c probabilistic
risk analyses.

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