Earthquake risk management of civil infrastructure: integrating soft and hard risks - Seismic Risk Analysis and Management of Civil Infrastructure Systems - page 225

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Earthquake risk management of civil
infrastructure: integrating soft and hard risks
D. BLOCKLEY, University of Bristol, UK
DOI : 10.1533/9780857098986.2.229
Abstract : Risk is an inevitable part of all human activity. Similarly sized
earthquakes can have very different impacts in different countries
depending on the degree of engineering input into the design and
construction of the facilities. In this chapter we will propose an approach
based on systems thinking and new systems boundaries. We will identify
and characterise three different sources of uncertainty: hard physical
system parameter uncertainty, hard system model uncertainty and soft
system human uncertainty. We will explore ways in which evidence from
previously disparate sources can be managed in an integrated way.
Key words : seismic risk, uncertainty, safety, systems thinking, integration,
hard and soft systems.
9.1 Introduction: the inevitability of risk
Risk is an inevitable part of all human activity. It is at the heart of all major
engineering questions. How do we know what is safe? How safe is safe
enough? Are any specifi c structures, or groups of structures, particularly
vulnerable? What are the chances of another Chernobyl disaster? How do
we deal with extreme weather such as hurricanes and fl ooding and, in par-
ticular for this volume, earthquakes? How do we learn from failure so
history does not keep repeating itself?
We know from everyday life that things do not always turn out as we
want and this is also true in engineering practice. Both everyday life and
engineering practice require us to use common sense when solving prob-
lems. We have to go through specifi c processes to get from where-we-are-
now to where-we-want-to-be at some time in the future. In doing so we
have to decide what we want, what we think we know, how we may achieve
what we want, what actually to do and fi nally what we think might be the
consequences. We know if things do not work out then the consequences
may range from minor upset to deep and major harm. Quite rightly, what
engineers do and the processes they go through are closely scrutinised and
can, ultimately, be tested in a court of law as a duty of care.
There is a much greater awareness of the need to deal explicitly with risk
in all aspects of life. In many projects, accountants manage the known
fi nancial risks well, engineers manage the known technological risks well,
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