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Terminology:
Basic terms of disaster risk reduction |
The ISDR Secretariat
presents these basic definitions on disaster risk reduction in order
to promote a common understanding on this subject, for use by the
public, authorities and practitioners. The terms are based on a broad
consideration of different international sources. This is a continuing
effort to be reflected in future reviews, responding to a need expressed
in several international venues, regional discussions and national
commentary. Feedback from specialists and other practitioners to
improve these definitions will be most welcome. |
Acceptable
risk |
The
level of loss a society or community considers acceptable given
existing social, economic, political, cultural, technical and
environmental conditions.
In
engineering terms, acceptable risk is also used to assess
structural and non-structural measures undertaken to
reduce possible damage at a level which does not harm
people and property, according to codes or "accepted
practice" based, among other issues, on a known
probability of hazard.
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Biological
hazard |
Processes
of organic origin or those conveyed by biological vectors,
including exposure to pathogenic micro-organisms, toxins and
bioactive substances, which may cause the loss of life or injury,
property damage, social and economic disruption or environmental
degradation.
Examples
of biological hazards: outbreaks of epidemic diseases,
plant or animal contagion, insect plagues and extensive
infestations.
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Building
codes |
Ordinances
and regulations controlling the design, construction, materials,
alteration and occupancy of any structure to insure human safety
and welfare. Building codes include both technical and functional
standards. |
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Capacity |
A combination
of all the strengths and resources available within a community,
society or organization that can reduce the level of risk,
or the effects of a disaster.
Capacity
may include physical, institutional, social or economic
means as well as skilled personal or collective attributes
such as leadership and management. Capacity may also
be described as capability.
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Capacity
building |
Efforts
aimed to develop human skills or societal infrastructures within
a community or organization needed to reduce the level of risk.
In
extended understanding, capacity building also includes
development of institutional, financial, political and
other resources, such as technology at different levels
and sectors of the society.
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Climate
change |
The climate
of a place or region is changed if over an extended period
(typically decades or longer) there is a statistically significant
change in measurements of either the mean state or variability
of the climate for that place or region.
Changes
in climate may be due to natural processes or to persistent
anthropogenic changes in atmosphere or in land use. Note
that the definition of climate change used in the United
Nations Framework Convention on Climate Change is more
restricted, as it includes only those changes which are
attributable directly or indirectly to human activity.
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Coping
capacity |
The means
by which people or organizations use available resources and
abilities to face adverse consequences that could lead to a
disaster.
In
general, this involves managing resources, both in normal
times as well as during crises or adverse conditions.
The strengthening of coping capacities usually builds
resilience to withstand the effects of natural and human-induced
hazards.
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Counter
measures |
All measures
taken to counter and reduce disaster risk. They most commonly
refer to engineering (structural) measures but can also include
non-structural measures and tools designed and employed to
avoid or limit the adverse impact of natural hazards and related
environmental and technological disasters. |
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Disaster |
A serious
disruption of the functioning of a community or a society causing
widespread human, material, economic or environmental losses
which exceed the ability of the affected community or society
to cope using its own resources.
A
disaster is a function of the risk process. It results
from the combination of hazards, conditions of vulnerability
and insufficient capacity or measures to reduce the potential
negative consequences of risk.
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Disaster
risk management |
The systematic
process of using administrative decisions, organization, operational
skills and capacities to implement policies, strategies and
coping capacities of the society and communities to lessen
the impacts of natural hazards and related environmental and
technological disasters. This comprises all forms of activities,
including structural and non-structural measures to avoid (prevention)
or to limit (mitigation and preparedness) adverse effects of
hazards. |
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Disaster
risk reduction (disaster reduction) |
The conceptual
framework of elements considered with the possibilities to
minimize vulnerabilities and disaster risks throughout a society,
to avoid (prevention) or to limit (mitigation and preparedness)
the adverse impacts of hazards, within the broad context of
sustainable development.
The
disaster risk reduction framework is composed of the
following fields of action, as described in ISDR's publication
2002 "Living with Risk: a global review of disaster
reduction initiatives", page 23:
- Risk
awareness and assessment including hazard analysis
and vulnerability/capacity analysis;
- Knowledge
development including education, training, research
and information;
- Public
commitment and institutional frameworks, including
organisational, policy, legislation and community action;
- Application
of measures including environmental management, land-use
and urban planning, protection of critical facilities,
application of science and technology, partnership
and networking, and financial instruments;
- Early
warning systems including forecasting, dissemination
of warnings, preparedness measures and reaction capacities.
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Early
warning |
The provision
of timely and effective information, through identified institutions,
that allows individuals exposed to a hazard to take action
to avoid or reduce their risk and prepare for effective response.
Early
warning systems include a chain of concerns, namely:
understanding and mapping the hazard; monitoring and
forecasting impending events; processing and disseminating
understandable warnings to political authorities and
the population, and undertaking appropriate and timely
actions in response to the warnings.
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Ecosystem |
A complex
set of relationships of living organisms functioning as a unit
and interacting with their physical environment.
The
boundaries of what could be called an ecosystem are somewhat
arbitrary, depending on the focus of interest or study.
Thus the extent of an ecosystem may range from very small
spatial scales to, ultimately, the entire Earth (IPCC,
2001).
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El
Niño-southern oscillation (ENSO) |
A complex
interaction of the tropical Pacific Ocean and the global atmosphere
that results in irregularly occurring episodes of changed ocean
and weather patterns in many parts of the world, often with
significant impacts, such as altered marine habitats, rainfall
changes, floods, droughts, and changes in storm patterns.
The
El Niño part of ENSO refers to the well-above-average
ocean temperatures along the coasts of Ecuador, Peru
and northern Chile and across the eastern equatorial
Pacific Ocean, while the Southern Oscillation refers
to the associated global patterns of changed atmospheric
pressure and rainfall. La Niña is approximately
the opposite condition to El Niño. Each El Niño
or La Niña episode usually lasts for several seasons.
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Emergency
management |
The organization
and management of resources and responsibilities for dealing
with all aspects of emergencies, in particularly preparedness,
response and rehabilitation.
Emergency
management involves plans, structures and arrangements
established to engage the normal endeavours of government,
voluntary and private agencies in a comprehensive and
coordinated way to respond to the whole spectrum of emergency
needs. This is also known as disaster management.
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Environmental
impact assessment (EIA) |
Studies
undertaken in order to assess the effect on a specified environment
of the introduction of any new factor, which may upset the
current ecological balance.
EIA
is a policy making tool that serves to provide evidence
and analysis of environmental impacts of activities from
conception to decision-making. It is utilised extensively
in national programming and for international development
assistance projects. An EIA must include a detailed risk
assessment and provide alternatives solutions or options.
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Environmental
degradation |
The reduction
of the capacity of the environment to meet social and ecological
objectives, and needs.
Potential
effects are varied and may contribute to an increase
in vulnerability and the frequency and intensity of natural
hazards.
Some
examples: land degradation, deforestation, desertification,
wildland fires, loss of biodiversity, land, water and
air pollution, climate change, sea level rise and ozone
depletion.
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Forecast |
Definite
statement or statistical estimate of the occurrence of a future
event (UNESCO, WMO).
This
term is used with different meanings in different disciplines.
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Geological
hazard |
Natural
earth processes or phenomena that may cause the loss of life
or injury, property damage, social and economic disruption
or environmental degradation.
Geological
hazard includes internal earth processes or tectonic
origin, such as earthquakes, geological fault activity,
tsunamis, volcanic activity and emissions as well as
external processes such as mass movements: landslides,
rockslides, rock falls or avalanches, surfaces collapses,
expansive soils and debris or mud flows.
Geological
hazards can be single, sequential or combined in their
origin and effects.
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Geographic
information systems (GIS) |
Analysis
that combine relational databases with spatial interpretation
and outputs often in form of maps. A more elaborate definition
is that of computer programmes for capturing, storing, checking,
integrating, analysing and displaying data about the earth
that is spatially referenced.
Geographical
information systems are increasingly being utilised for
hazard and vulnerability mapping and analysis, as well
as for the application of disaster risk management measures.
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Greenhouse
gas (GHG) |
A gas, such
as water vapour, carbon dioxide, methane, chlorofluorocarbons
(CFCs) and hydrochlorofluorocarbons (HCFCs), that absorbs and
re-emits infrared radiation, warming the earth's surface and
contributing to climate change (UNEP, 1998). |
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Hazard |
A potentially
damaging physical event, phenomenon or human activity that
may cause the loss of life or injury, property damage, social
and economic disruption or environmental degradation.
Hazards
can include latent conditions that may represent future
threats and can have different origins: natural (geological,
hydrometeorological and biological) or induced by human
processes (environmental degradation and technological
hazards). Hazards can be single, sequential or combined
in their origin and effects. Each hazard is characterised
by its location, intensity, frequency and probability.
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Hazard
analysis |
Identification,
studies and monitoring of any hazard to determine its potential,
origin, characteristics and behaviour. |
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Hydrometeorological
hazards |
Natural
processes or phenomena of atmospheric, hydrological or oceanographic
nature, which may cause the loss of life or injury, property
damage, social and economic disruption or environmental degradation.
Hydrometeorological
hazards include: floods, debris and mud floods; tropical
cyclones, storm surges, thunder/hailstorms, rain and
wind storms, blizzards and other severe storms; drought,
desertification, wildland fires, temperature extremes,
sand or dust storms; permafrost and snow or ice avalanches.
Hydrometeorological hazards can be single, sequential
or combined in their origin and effects.
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La
Niña |
(see El
Niño-Southern Oscillation). |
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Land-use
planning |
Branch of
physical and socio-economic planning that determines the means
and assesses the values or limitations of various options in
which land is to be utilized, with the corresponding effects
on different segments of the population or interests of a community
taken into account in resulting decisions.
Land-use
planning involves studies and mapping, analysis of environmental
and hazard data, formulation of alternative land-use
decisions and design of a long-range plan for different
geographical and administrative scales.
Land-use
planning can help to mitigate disasters and reduce risks
by discouraging high-density settlements and construction
of key installations in hazard-prone areas, control of
population density and expansion, and in the siting of
service routes for transport, power, water, sewage and
other critical facilities.
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Mitigation |
Structural
and non-structural measures undertaken to limit the adverse
impact of natural hazards, environmental degradation and technological
hazards. |
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Natural
hazards |
Natural
processes or phenomena occurring in the biosphere that may
constitute a damaging event.
Natural
hazards can be classified by origin namely: geological,
hydrometeorological or biological. Hazardous events can
vary in magnitude or intensity, frequency, duration,
area of extent, speed of onset, spatial dispersion and
temporal spacing.
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Preparedness |
Activities
and measures taken in advance to ensure effective response
to the impact of hazards, including the issuance of timely
and effective early warnings and the temporary evacuation
of people and property from threatened locations.
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Prevention |
Activities
to provide outright avoidance of the adverse impact of hazards
and means to minimize related environmental, technological
and biological disasters.
Depending
on social and technical feasibility and cost/benefit
considerations, investing in preventive measures is justified
in areas frequently affected by disasters. In the context
of public awareness and education, related to disaster
risk reduction changing attitudes and behaviour contribute
to promoting a "culture of prevention".
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Public
awareness |
The processes
of informing the general population, increasing levels of consciousness
about risks and how people can act to reduce their exposure
to hazards. This is particularly important for public officials
in fulfilling their responsibilities to save lives and property
in the event of a disaster.
Public
awareness activities foster changes in behaviour leading
towards a culture of risk reduction. This involves public
information, dissemination, education, radio or television
broadcasts, use of printed media, as well as, the establishment
of information centres and networks and community and
participation actions.
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Public
information |
Information,
facts and knowledge provided or learned as a result of research
or study, available to be disseminated to the public. |
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Recovery |
Decisions
and actions taken after a disaster with a view to restoring
or improving the pre-disaster living conditions of the stricken
community, while encouraging and facilitating necessary adjustments
to reduce disaster risk.
Recovery
(rehabilitation and reconstruction) affords an opportunity
to develop and apply disaster risk reduction measures.
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Relief
/ response |
The provision
of assistance or intervention during or immediately after a
disaster to meet the life preservation and basic subsistence
needs of those people affected. It can be of an immediate,
short-term, or protracted duration. |
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Resilience
/ resilient |
The capacity
of a system, community or society potentially exposed to hazards
to adapt, by resisting or changing in order to reach and maintain
an acceptable level of functioning and structure. This is determined
by the degree to which the social system is capable of organizing
itself to increase its capacity for learning from past disasters
for better future protection and to improve risk reduction
measures. |
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Retrofitting
(or upgrading) |
Reinforcement
of structures to become more resistant and resilient to the
forces of natural hazards.
Retrofitting
involves consideration of changes in the mass, stiffness,
damping, load path and ductility of materials, as well
as radical changes such as the introduction of energy
absorbing dampers and base isolation systems. Examples
of retrofitting includes the consideration of wind loading
to strengthen and minimize the wind force, or in earthquake
prone areas, the strengthening of structures.
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Risk |
The probability
of harmful consequences, or expected losses (deaths, injuries,
property, livelihoods, economic activity disrupted or environment
damaged) resulting from interactions between natural or human-induced
hazards and vulnerable conditions.
Conventionally
risk is expressed by the notation
Risk = Hazards x Vulnerability. Some disciplines also include the
concept of exposure to refer particularly to the physical aspects
of vulnerability.
Beyond
expressing a possibility of physical harm, it is crucial
to recognize that risks are inherent or can be created
or exist within social systems. It is important to consider
the social contexts in which risks occur and that people
therefore do not necessarily share the same perceptions
of risk and their underlying causes.
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Risk
assessment/analysis |
A methodology
to determine the nature and extent of risk by analysing potential
hazards and evaluating existing conditions of vulnerability
that could pose a potential threat or harm to people, property,
livelihoods and the environment on which they depend.
The
process of conducting a risk assessment is based on a
review of both the technical features of hazards such
as their location, intensity, frequency and probability;
and also the analysis of the physical, social, economic
and environmental dimensions of vulnerability and exposure,
while taking particular account of the coping capabilities
pertinent to the risk scenarios.
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Structural
/ non-structural measures |
Structural
measures refer to any physical construction to reduce or avoid
possible impacts of hazards, which include engineering measures
and construction of hazard-resistant and protective structures
and infrastructure.
Non-structural
measures refer to policies, awareness, knowledge development,
public commitment, and methods and operating practices,
including participatory mechanisms and the provision
of information, which can reduce risk and related impacts.
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Sustainable
development |
Development
that meets the needs of the present without compromising the
ability of future generations to meet their own needs. It contains
within it two key concepts: the concept of "needs",
in particular the essential needs of the world's poor, to which
overriding priority should be given; and the idea of limitations
imposed by the state of technology and social organization
on the environment's ability to meet present and the future
needs. (Brundtland Commission, 1987).
Sustainable
development is based on socio-cultural development, political
stability and decorum, economic growth and ecosystem
protection, which all relate to disaster risk reduction.
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Technological
hazards |
Danger originating
from technological or industrial accidents, dangerous procedures,
infrastructure failures or certain human activities, which
may cause the loss of life or injury, property damage, social
and economic disruption or environmental degradation.
Some
examples: industrial pollution, nuclear activities and
radioactivity, toxic wastes, dam failures; transport,
industrial or technological accidents (explosions, fires,
spills).
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Vulnerability |
The conditions
determined by physical, social, economic, and environmental
factors or processes, which increase the susceptibility of
a community to the impact of hazards.
For
positive factors, which increase the ability of people
to cope with hazards, see definition of capacity.
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Wildland
fire |
Any fire
occurring in vegetation areas regardless of ignition sources,
damages or benefits. |
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Updated
31-03-04
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