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Abstract
Abstract. The effects of natural hazards can be mitigated
by the use of proper \u201cpre-event\u201d interventions on \u201ckey\u201d elements
of the territory, that is on elements that are mostly
vulnerable to a given catastrophic scenario and whose loss
of functionality can cause damages on people, property and
environment. In this respect, methodologies and tools should
be studied to support decision makers in the analysis of a territory,
in order to point out such elements. In this work, vulnerability
is taken into account under two aspects: \u201cphysical
vulnerability\u201d, which measures the propensity of a territorial
element to suffer damage when subject to an external stress
corresponding to the occurrence of a natural phenomenon;
\u201cfunctional vulnerability\u201d, which measures the propensity of
a territorial element to suffer loss in functionality, even when
that is caused by the loss of functionality of other territorial
elements. In the proposed modeling approach, vulnerability
is represented through the use of a graph-based formalization.
A territorial system is represented as a complex set of
elements or sub-systems. Such elements have differentiated
and dedicated functions, and they may be functionally interconnected
among them. In addition, vulnerability is defined
through the use of two different variables, namely the criticality
and the efficiency. Focusing the attention on the temporal
phases corresponding to the occurrence of a calamitous
event, the first one measures the service demand of an element,
whereas the efficiency is a measure of the service that
can be offered by such an element. The approach presented
is largely independent from the natural risk considered. Besides,
the tools introduced for the vulnerability analysis of
the territorial system can also be used to formalize decision
problems relevant to the location of the available resources
for emergency management. A specific case study pertaining
to the hydrological risk in the Val di Vara area (Italy) is
presented