Natural Hazards, Natural Disasters and Risk
Natural Hazards Vs. Natural Disasters
Natural Hazard: A perceived, naturally occurring process or event that has the potential to affect people.
Under certain conditions, a natural hazard can become a disaster. Exactly when this happens is hard to define, but
generally a disaster happens when a natural hazard strikes a vulnerable population that can’t cope using its own
resources.
Natural Disaster: The reality of a major natural hazard that causes significant social, environmental and economic
damage.
The greater the scale of the natural hazard, and the more vulnerable the population, the greater the disaster will be.
Vulnerability: The ability to anticipate, cope with, resist and recover from a natural hazard.
Degg’s Model
Degg’s model shows how the overlap of a natural
hazard and vulnerability can cause a disaster.
Risk
The level of risk a country face from natural hazards depends on a combination of factors.
● Some of these are directly related to the hazard itself, e.g. (in the case of an earthquake) its magnitude,
duration, etc.
● Human factors also play as much – if not more – of a role determining vulnerability and capacity to cope.
(Case study examples: to compare impacts: Haiti 2008 Earthquake vs. Sichuan 2008 Earthquake or
Northridge 1994 Earthquake; to compare responses: Haiti 2008 Earthquake vs. Japan 2011 Tsunami).
Hazard-Risk Equation
The hazard-risk equation attempts to capture the various components that influence the amount of risk that a hazard
may produce for a community or population.
Risk = Hazard × Exposure × Vulnerability
Manageability
● Perception of risks can also drive a population to the point where they have to adjust to the presence of the
risk.
● People and populations also vary in terms of resilience.
● According to the United Nations Office for Disaster Risk Reductions (UNISDR) the resilience of a
community is based on resources and organisation before and during disasters.
, Vulnerability and Resilience
Resilience: The ability to protect lives, livelihoods and infrastructure from destruction, and to restore areas after a
natural hazard has occurred.
Human factors and decisions affect vulnerability and resilience. Less-developed countries are generally more
vulnerable to hazard events than wealthier countries – because they tend to have other, more immediate issues (e.g.
poverty, disease), they’re less able to spend money on preparing for natural hazard events.
Human Factors Affecting Vulnerability
Governance and Political Conditions
● The existence and the enforcement of building codes and regulations determine the quality and safety of buildings and
other structures.
● The quality of the existing infrastructure (e.g. transport, power supplies) affects a country’s recovery speed.
● The existence of disaster preparedness plans influences how quickly and effectively a country responds to and recovers
from a hazard event.
● The efficiency of emergency services and response teams affects the speed and effectiveness of rescue efforts.
● The quality of communication systems affects the ability to inform people of a hazard in advance, and to coordinate
rescue efforts.
● The existence of public education and practised hazard responses such as earthquake drills influences a population’s
preparedness for and responses to a hazard event.
● The level of corruption of government officials and businesses influences how resources are used.
Economic and Social Conditions
● Their level of wealth influences people’s ability to protect themselves and then recover from a natural hazard.
● People without access to education may be less aware of the risks of a hazard event and how to protect
themselves.
● Poor quality housing is less able to withstand the impact of natural hazards.
● Communities with poor health care suffer more disease and are less able to cope with and recover.
● A lack of income opportunities means that people cannot buy the resources they need to prepare for ir cope
with a hazard, and this can affect their health care and living conditions.
Physical and Environmental Conditions
● Areas with a high population density tend to have more low-quality housing.
● Rapid urbanisation creates a need for more housing – most of which is built quickly and of poor quality.
● The accessibility of an area affects how quickly rescuers and aid can arrive.
Types of Vulnerability
Physical Vulnerability When people live in hazard prone areas in buildings that offer little protection.
Economic Vulnerability People risk losing their jobs, assets and money.
Social Vulnerability When a household or community is unable to support the disadvantaged people
within it.
Knowledge Vulnerability Exists when people lack education or training, and there are no warning or evacuation
systems in place.
Environmental Vulnerability Exists where the area that people are living in has increased in hazard risk because of
population pressure, forcing people into riskier areas.
