4. The exposure to hazard, or assumed risk, is usually involuntary, mainly because
the persons are located in hazardous areas.
5. The intensity of the ensuing disaster is high enough to justify an emergency
response, ranging from local to international help.
12.2.2 Hazard and Risk
As explained in para 11.5.1, a hazard (possible danger source) can be a humaninduced process (building on steep slopes) or naturally occurring event (floods,
hurricanes) with the potential to create loss. The exposure, to a hazard, of anything
valuable to humans is considered a risk – which is often taken as the combination of
probability and loss. Thus, a hazard is a potential threat to humans and their welfare,
and risk (or consequence) is the probability of occurrence of a specific hazard.
Consider two passengers in a boat, with one wearing a life jacket while the other
does not. In case the boat capsizes, the main hazard (deep water) is the same for both
passengers but the risk (probability of drowning) is greater for the passenger who has
not learnt how to swim and who is not wearing a life jacket.
In the same way, if landslides can occur in two nearby regions – an inhabited area
and a deserted one – a landslide hazard exists in both areas, but the landslide risk
exists only for the populated area.
When carrying out risk assessment of disasters, it is essential to consider the
number of people and what they consider as valuable. Usually, when a high number
of persons are exposed to a hazard and are injured or killed, the event is called a
disaster. Thus, a disaster is the implementation of a hazard, on a large scale. The
notion of magnitude and scale are discussed further below.
Hazard, risk and disaster operate on varying scales. Table 12.1 lists down threats
in decreasing order of severity.
12.2.3 Vulnerability
When a hazardous event takes place, the system or sub-system may react adversely
to it. The degree to which this may happen is defined as vulnerability. The notion of
Table 12.1 List of threats
Hazards
Threats
People
Injury or death, diseases, stress and trauma
Goods
Damage to private property and State (national) property
Environment
Loss of green areas, flora and fauna
Development
Pace of development may slow down or get interrupted, loss of livelihood
336
12 Disaster Recovery and Management
the persons are located in hazardous areas.
5. The intensity of the ensuing disaster is high enough to justify an emergency
response, ranging from local to international help.
12.2.2 Hazard and Risk
As explained in para 11.5.1, a hazard (possible danger source) can be a humaninduced process (building on steep slopes) or naturally occurring event (floods,
hurricanes) with the potential to create loss. The exposure, to a hazard, of anything
valuable to humans is considered a risk – which is often taken as the combination of
probability and loss. Thus, a hazard is a potential threat to humans and their welfare,
and risk (or consequence) is the probability of occurrence of a specific hazard.
Consider two passengers in a boat, with one wearing a life jacket while the other
does not. In case the boat capsizes, the main hazard (deep water) is the same for both
passengers but the risk (probability of drowning) is greater for the passenger who has
not learnt how to swim and who is not wearing a life jacket.
In the same way, if landslides can occur in two nearby regions – an inhabited area
and a deserted one – a landslide hazard exists in both areas, but the landslide risk
exists only for the populated area.
When carrying out risk assessment of disasters, it is essential to consider the
number of people and what they consider as valuable. Usually, when a high number
of persons are exposed to a hazard and are injured or killed, the event is called a
disaster. Thus, a disaster is the implementation of a hazard, on a large scale. The
notion of magnitude and scale are discussed further below.
Hazard, risk and disaster operate on varying scales. Table 12.1 lists down threats
in decreasing order of severity.
12.2.3 Vulnerability
When a hazardous event takes place, the system or sub-system may react adversely
to it. The degree to which this may happen is defined as vulnerability. The notion of
Table 12.1 List of threats
Hazards
Threats
People
Injury or death, diseases, stress and trauma
Goods
Damage to private property and State (national) property
Environment
Loss of green areas, flora and fauna
Development
Pace of development may slow down or get interrupted, loss of livelihood
336
12 Disaster Recovery and Management