A capability approach for seismic risk analysis and management - Seismic Risk Analysis and Management of Civil Infrastructure Systems - page 253

course, precludes any benefi ts from activities within the structure. Thus, the
decision to build a structure itself entails some risk that can be tolerated
because of the benefi ts of the building or facility.'
Judging a risk to be unacceptable typically implies that action should be
taken by a community to mitigate such risks. However, mitigating or guard-
ing against certain losses requires resources, which could be put to other
uses if not devoted to such mitigation. In addition, communities often are
vulnerable to multiple hazards. Thus, determining the level of risk that is
acceptable (or target levels of safety in reverse) in part involves deciding
whether mitigation action should be triggered if a risk is judged to be unac-
ceptable (or the relationship between standards for mitigation action and
acceptable risk) (Murphy and Gardoni 2007, 2008; Gardoni and Murphy
2008).
Finally, determining target levels of performance and acceptable levels
of risk requires understanding the possible negative consequences of haz-
ardous scenarios, or losses due to a seismic event, and benefi ts from accept-
ing certain risks (Lindell and Prater 2003; Cutter et al. 2003; Murphy and
Gardoni 2007; Gardoni and Murphy 2008). Identifying and measuring
losses involves value judgment about which kind(s) of potential losses
should be considered and what metric should be used to assess such losses.
Potential losses must be defi ned in a way that captures the indirect and
broader ramifi cations that hazards can have for communities (May 2001).
There are a number of widely recognized challenges to developing a
satisfactory metric for gauging potential consequences of hazardous sce-
narios (for a comprehensive summary of these challenges see Murphy and
Gardoni, 2006, and Gardoni and Murphy, 2009). Losses can be conceptual-
ized in terms of lost capital ('including repair and replacement costs for
structural and nonstructural components, buildings content loss, business
inventory loss') or income ('business interruption, lost wages') in an annual-
ized manner (May 2001). The choice of metric is important in part because
it can infl uence how risks of various kinds are ranked. In particular, the way
in which value should be assigned to human life, and whether, for example,
to assign different values to different life expectancies or voluntary expo-
sure to risk (Stern and Fineberg 1996, pp. 52-53) is the subject of ongoing
dispute. When market values are used to assess losses, valuation of non-
market goods, such as sustainability, becomes more complicated (Gardoni
and Murphy 2008).
These considerations suggest a number of desiderata that an approach
for seismic risk analysis and management ought to satisfy. Such desiderata
are discussed in the next section. Next, the chapter presents a capability
approach for seismic risk analysis and management. Finally, the chapter
discusses the benefi ts of a capability approach over traditional approaches
available in the literature.