Introduction - Extreme Events: A Physical Reconstruction and Risk Assessment - page 3

risk assessments. Through familiarity, though, comes awareness of the insights
that the prehistoric record can provide into gaining a more realistic impression
of the behaviour of natural hazards.

The risk assessment process

Risk from natural hazards is a function of the nature of the natural
hazard (i.e. probability of its occurrence), community vulnerability and the ele-
ments at risk. Risk can have a variety of meanings and is sometimes used in the
sense of the probability or chance that an event will happen within a specific
period of time. Alternatively, risk can refer to the outcomes of an event occur-
ring. In this latter sense, risk refers to the expected number of lives lost, persons
injured, damage to property and disruption of economic activity due to a partic-
ular natural phenomenon. Risk is really the product of the specific risk and the
elements at risk. The specific risk here means the expected degree of loss due to
aparticular natural phenomenon and is a function of both the natural hazard
and vulnerability (Fournier d'Albe, 1986). The elements at risk, otherwise known
as the level of exposure, refers to the population, buildings, economic activities,
public services, utilities and infrastructure that may be directly impacted by the
hazard.
Community vulnerability is determined by the social and demographic
attributes that influence a person's perception of the risk to the hazard. It
often concerns peoples' attitudes, preparedness and willingness to respond to
warnings of an impending hazard. Anderson-Berry (2003)notes that community
vulnerability is not a static state but a dynamic process. It is generated by the
complex relationships and inter-relationships arising from the unique actions
and interactions of the social and community attributes and characteristics of
aparticular population.
These attributes and characteristics include:

societal structures, infrastructure and institutions including the

integrity of physical structures;
community processes and structures such as community organisation,
mobility of the household population, and community cohesiveness and
thesocial support this affords; and
demographic and other characteristics of individuals within the com-
munity such as age, ethnicity, education and wealth (Keys, 1991;
Fothergill, 1996;Buckle, 1999;Fothergill et al ., 1999;Cannon,2000).

These factors, along with actual experiences of the hazard in question, help to
shape the individual's and the community's perception of risk. Anderson-Berry