The Glossary of Disaster Risk Reduction

Community based Disaster Risk Reduction Programme –  DISASTER DICTIONARY

Acceptable risk: The probability of occurrences of physical, social, or economic consequences of an earthquake that is considered to be sufficiently low in comparison with the risks from other natural or technological hazards that these occurrences are accepted as realistic reference points for determining design requirements for structures, or for taking social, political, legal, and economic actions in the community to protect people and property. The level of loss a society or community considers acceptable given existing social, economic, political, cultural, technical and environmental conditions.

Absorbing capacity: the buffering ability that enables a society to dissipate the effects of an event. It is a function of the level of preparedness of the society to respond to the event plus the resilience of the population and environment.Absorbing capacity = resilience + preparedness

Active fault: A fault is active if it exhibits physical characteristics such as historic earthquake activity, surface fault rupture, geologically recent displacement of stratigraphy or topography, or physical association with another fault system judged to be active. When these characteristics are suspected or proven, it is classed as active and judged to be able to undergo movement.

Adverse effect The first visually perceptible change; a specific chemical or physical characteristic of the material/object usually considered abnormal or undesirable. This term is commonly used for risk analysis in the fields of health, safety, and environmental policy. Aftershocks The long, exponentially decaying sequence of smaller earthquakes that follow a large-magnitude earthquake for months to years, exacerbating the damage. A type of ground failure.

Avalanche Sudden slide of a huge mass of snow and ice, usually carrying with it earth, rocks, trees and other debris.

Awareness The continual process of collecting, analyzing, and disseminating intelligence, information, and knowledge to allow organizations and individuals to anticipate and react effectively.

Biohazard Biological agents and materials that are potentially hazardous to humans, animals, or plants, which include infectious or disease-causing agents, potentially infectious materials, certain toxins, and other hazardous biological materials.

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.

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.

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.

Capacity, adaptive (Capacity adaptive) Defines adaptive capacity as a combination of a society’s ex-ante vulnerability to damages from natural hazards and its ex post resilience or ability to cope with the damages that result. Capacity, Coping and Adaptive (Coping and Adaptive Capacity) While the concept of coping capacity is more directly related to an extreme event (e.g. a flood or a winter storm), the concept of adaptive capacity refers to a longer time frame and implies that some learning either before or after an extreme event is happening. The higher the coping capacity and adaptive capacity, the lower the vulnerability of a system, region, community or household. Enhancement of adaptive capacity is a necessary condition for reducing vulnerability, particularly for the most vulnerable regions and socioeconomic groups.

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.

Contingency plan/Emergency plan An anticipatory emergency plan to be followed in an expected or eventual disaster, based on risk assessment, availability of human and material resources, community preparedness, local and international response capability, etc. 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.

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. Disaster is sometimes also used to describe a catastrophic situation in which the normal patterns of life (or eco-systems) have been disrupted and extraordinary, emergency interventions are required to save and preserve human lives and/or the environment.

Disasters are frequently categorized according to their perceived causes and speed of impact. 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. The result of a vast ecological breakdown in the relations between man and his environment, a serious and sudden event (or slow, as in drought) on such a scale that the stricken community need extraordinary efforts to cope with it, often with outside help or international aid.

Disasters combine two elements: events and vulnerable people. A disaster occurs when a disaster agent (the event) exposes the vulnerability of individuals and communities in such a way that their lives are directly threatened or sufficient harm has been done to their community’s economic and social structures to undermine their ability to survive. A disaster is fundamentally a socio-economic phenomenon. It is an extreme but not necessarily abnormal state of everyday life in which the continuity of community structures and processes temporarily fails. Social disruption may typify a disaster but not social disintegration. A disaster by itself is an impact of a hazard on a community or area – usually defined as an event that overwhelms the capacity to cope with it.

Disaster is defined as the set of adverse effects caused by social-natural and natural phenomena on human life, properties and infrastructure within a specific geographic unit during a given period of time. Process involving the combination of a potentially destructive agent(s) from the natural, modified and/or constructed environment and a population in a socially and economically produced condition of vulnerability, resulting in a perceived disruption of the customary relative satisfactions of individual and social needs for physical survival, social order and meaning. A disaster is made inevitable by the historically produced pattern of vulnerability, evidenced in the location, infrastructure, sociopolitical structure, production patterns, and ideology that characterize a society. The society’s pattern of vulnerability is an essential element of a disaster. Disasters are often classified according to their speed of onset (sudden or slow) or according to their cause (natural, man-made, or unexpected).

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. Comprehensive approach and activities to reduce the adverse impacts of disasters. It encompasses all actions taken before, during, immediately after, and some time after a disaster. It is holistic and includes activities on mitigation, preparedness, emergency response, recovery, rehabilitation, and reconstruction.

Disaster risk reduction (disaster reduction) All actions taken to decrease the consequences of an event including measures of prevention, mitigation, preparedness, response, and research. 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.

Disaster Medicine The combination of medical and medico-organizational measures undertaken in case of disaster covering the entire range of medical care from the scene of the disaster to the hospital bed.

Disaster Mitigation Separate and aggregate measures taken prior to or following a disaster to reduce the severity of the human and material damage caused by it. Mitigation refers to measures which can be taken to minimize the destructive and disruptive effects of hazards and thus lessen the magnitude of a disaster. Mitigation measures can be of different kinds, ranging from physical measures such as flood defences or safe building design, to legislation, training and public awareness. Mitigation is an activity which can take place at any time: before a disaster occurs, during an emergency, or after disaster, during recovery or reconstruction.

Disaster Preparedness The aggregate of measures to be taken in view of disasters, consisting of plans and action programmes designed to minimize loss of life and damage, to organize and facilitate effective rescue and relief, and to rehabilitate after disaster. Preparedness requires the necessary legislation and means to cope with disaster or similar emergency situations. It is also concerned with forecasting and warning, the education and training of the public, organization and management, including plans, training of personnel, the stockpiling of supplies and ensuring the needed funds and other resources. The state of readiness on the part of the government and society to respond effectively to a disaster and to recover quickly from its effects. Disaster Preparedness includes preparing and testing emergency response plans, training, acquiring and maintaining equipment needed for response, stockpiling relief materials, etc. The purpose of preparedness is to anticipate likely impacts of disasters so that ways can be devised to effectively mitigate major adverse effects. Measures that ensure the readiness and ability of a society to (a) forecast and take precautionary measures in advance of an imminent threat (in cases where advance warnings are possible), and (b) respond to and cope with the effects of a disaster by organizing and delivering timely and effective rescue, relief and other appropriate post-disaster assistance. Preparedness involves the development and regular testing of warning systems (linked to forecasting systems) and plans for evacuation or other measures to be taken during a disaster alert period to minimize potential loss of life and physical damage; the education and training of officials and the population at risk; the establishment of policies, standards, organizational arrangements and operational plans to be applied following a disaster impact; the securing of resources (possibly including the stockpiling of supplies and the earmarking of funds); and the training of intervention teams. It must be supported by enabling legislation. The aggregate of all measures and policies taken by humans before the event for reduction of the damage that otherwise would have resulted from the event and coping with the damage sustained.

Disaster Prevention The aggregate of approaches and measures to ensure that human action or natural phenomena do not cause or result in disaster or similar emergency. It implies the formulation and implementation of long range policies and programmes to eliminate or prevent the occurrence of disasters. Based on vulnerability analysis of risks, it also includes legislation and regulatory measures in the field of town planning, public works and environmental development. The aggregate of approaches and measures taken to ensure that a hazard does not cause a disaster, either by preventing the event or by mitigating activities, or by activities and structures that are able to absorb the event.

Damage assessment The process of determining the magnitude of damage to and the unmet needs of the private sector and the public sector caused by a crisis. Human-Made Disasters Disaster or emergency situation of which the principal, direct causes are identifiable human actions, deliberate or otherwise. Apart from “technological disasters” this mainly involves situations in which civilian populations suffer casualties, losses of property, basic services and means of livelihood as a result of war, civil strife, other conflict or policy implementation. In many cases, people are forced to leave their homes, giving rise to congregations of refugees or externally or internally displaced persons.

Slow-Onset Disasters (also called Creeping Disasters or Slow-onset Emergencies) Situations in which the ability of people to sustain their livelihood slowly declines to a point where survival is ultimately jeopardized. Such situations are typically brought on or precipitated by ecological, social, economic or political conditions. Sudden-Onset Natural Disasters Sudden calamities caused by natural phenomena such as earthquakes, floods, tropical storms, volcanic eruptions. They strike with little or no warning and have an immediate adverse effect on human populations, activities, and economic systems. Technological Disasters Situations in which large numbers of people, property, infrastructure, or economic activity are directly and adversely affected by major industrial accidents, severe pollution incidents, nuclear accidents, air crashes (in populated areas), major fires, or explosions.

Post Disaster Assessment (sometimes called Damage and Needs Assessment) The process of determining the impact of a disaster or events on a society, the needs for immediate, emergency measures to save and sustain the lives of survivors, and the possibilities for expediting recovery and development. Assessment is an interdisciplinary process undertaken in phases and involving on-the-spot surveys and the collation, evaluation and interpretation of information from various sources concerning both direct and indirect losses, short and long-term effects. It involves determining not only what has happened and what assistance might be needed, but also defining objectives and how relevant assistance can actually be provided to the victims. It requires attention to both short-term needs and long-term implications.

Disaster cycle An explicit typology for disaster planning, comprised of four phases: mitigation, preparedness, response, and recovery. Disaster drill A simulation of a  disaster to assess and improve the effectiveness of a health care organization’s or system’s emergency management plan.

Disaster epidemiology The study of disaster-related deaths, illnesses, and injuries in humans, which also includes the study of the factors that affect death, illness, and injury following a disaster. The methodology involves identifying and comparing risk factors among disaster victims to those who were left unharmed. Epidemiological investigations provide public health professionals with information on the probable public health consequences of disasters.

Disaster Management A collective term encompassing all aspects of planning for and responding to disasters, including both pre- and post-disaster activities. It may refer to the management of both the risks and consequences of disasters. The aggregate of all measures taken to reduce the likelihood of damage that will occur related to a hazard or hazards, all measures taken to minimize the damage once an event is occurring or has occurred, and all measures taken to direct recovery from the damage. The body of policy and administrative decisions and operational activities that pertain to the various stages of a disaster at all levels.

Disaster plan A formal written plan of action for coordinating the response of an organization in the event of a disaster within the organization or the community. Disaster vulnerability A measure of the ability of a community to absorb the effects of a severe disaster and to recover. Vulnerability varies with each disaster, depending on the disaster’s impact on the affected population or group.

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.

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 endeavors 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. The efforts of state and political subdivisions to develop, plan, analyze, conduct, provide, implement, and maintain programs for disaster mitigation, preparedness, response, and recovery. The function of organizations concerned with ensuring that their organization can continue to function during and after a crisis.

Emergency Preparedness Measures taken in advance of an emergency to reduce the loss of life and property and to protect a nation’s people and institutions from all types of hazards through a comprehensive emergency management program of preparedness, mitigation, response, and recovery.

Emergency Support Function (ESF) A grouping of government and certain private- sector capabilities into an organizational structure to provide the support, resources, program implementation, and services that are most likely to be needed to save lives, protect property and the environment, restore essential services and critical infrastructure, and help victims and communities return to normal, when feasible, following domestic incidents. The ESFs serve as the primary operational-level mechanism to provide assistance to state, local, and tribal governments or to federal departments and agencies conducting missions of primary federal responsibility. An element of many emergency plans, including the National Response Plan, which groups emergency capabilities and resources into functions that are most likely needed during an incident, e.g., transportation, firefighting, mass care. emergency support function mass care (ESF 6) The function dealing with mass care, which includes sheltering and feeding victims of disaster, emergency first aid, family reunification, and the distribution of emergency relief supplies. The American Red Cross is designated by the National Response Plan as the primary agency responsible for ESF mass care, emergency support function health and medical (ESF 8) led by the U.S. Public Health Service’s Office of Emergency Preparedness, ESF 8 serves as the basis for federal response to the health needs of disaster victims. Earthquake the violent shaking of the ground produced by deep seismic waves, beneath the epicenter, generated by a sudden decrease or release in a volume of rock of elastic strain accumulated over a long time in regions of seismic activity (tectonic earthquake). The magnitude of an earthquake is represented by the Richter scale; the intensity by the Mercalli scale.

Earthquake cycle The concept holds that two comparable sized earthquakes rupturing the same segment of a fault will be separated by a period of time long enough to re- accumulate strain in the amount equal to the elastic strain drop in the first earthquake. The stages in the cycle are: 1)a long period of seismic quiescence, except for the aftershocks, following a major earthquake, 2)a shorter period of increased seismicity as elastic strain accumulation approaches the critical strain level, and 3) the next major earthquake as the critical strain level is suddenly exceeded.

Earthquake hazards The physical effects generated in an earthquake (e.g., ground shaking, ground failure, surface fault rupture, regional tectonic deformation, tsunami run up, seiches, and aftershocks). Earthquake resistant buildings buildings that are sited, designed and constructed in such a way that they are able to resist the ground shaking from large-magnitude earthquakes without collapsing and from moderate-magnitude earthquakes without significant loss of function and with damage that is repairable. Earth Effect(s) the consequences of an event. The effects may be single, but most often are multiple and involve multiple basic functions. Any or all of the basic functions of the society affected may become impaired as part of the effects of the impact:

  • 1) Medical services;
  • 2) Public health;
  • 3) Sanitation and water supplies;
  • 4) Food; 5) Shelter/clothing;
  • 6) Energy supply;
  • 8) Public works;
  • 9) Environment;
  • 10) Logistics/transportation;
  • 11) Security;
  • 12) Communications; and/or
  • 13) Economy.

In addition, the structure that provides for Coordination and Control of these functions may become impaired or inoperative. effects may be acute and have a short time course or may have several phases usually described as

  • 1) alert/notification;
  • 2) response and recovery;
  • 3) reconstruction and rehabilitation.

It is important to recognize that there may be primary and secondary effects of an event. Primary effects are those that are a direct result of the event. Secondary effects are those that result from the primary effects or from the responses to the event. Although described as acute, some effects may be ongoing and stretch over long periods of time (e.g., famine, drought, epidemics, complex human emergencies). These effects are functions of the vulnerability of the population and the environment and to the human responses to the impact of the event.

Emergency a sudden and usually unforeseen event that must be countered immediately to minimize the consequences. The term is often used for disaster. With rational planning, emergencies can be tackled more effectively.

Emergency Response Actions taken during and immediately after a disaster to ensure that its adverse effects are minimized and that people affected are given immediate relief and support. It includes search and rescue, relief services, as well as restoration of power, water, and telephone services.

Epicenter The point on the earth’s surface vertically above the subsurface point where the fault rupture originated.

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 utilized extensively in national programming and for international development assistance projects. An EIA must include a detailed risk assessment and provide alternatives solutions or options.

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, wild land fires, loss of biodiversity, land, water and air pollution, climate change, sea level rise and ozone depletion.

Fault A fracture or a zone of fractures in the earth along which displacement of the two sides relative to one another has occurred as a consequence of compression, tension, or shearing stresses. A fault may rupture the ground surface during an earthquake, especially if the magnitude is greater than M 5.5. The length of the fault is related to the maximum magnitude, with long faults able to generate larger-magnitude earthquakes than short faults.

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.

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.

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. Anything that may pose a danger; thus, it is used in this discussion to mean a natural or human-made phenomenon that has the potential to adversely affect human health, property, activity, and/or the environment. The probability of the occurrence of a disaster caused by a natural phenomenon (earthquake, cyclone), or by failure of man-made sources of energy (nuclear reactor, industrial explosion) or by uncontrolled human activity (overgrazing, heavy traffic, conflicts). A potential threat to humans and their welfare.

The earthquake hazard is an example. An event or physical condition that is a potential cause of fatalities, injuries, property damage, infrastructure damage, agricultural loss, environmental damage, business interruption, or other types of harm or loss. The magnitude of the phenomenon, the probability of its occurrence, and the extent and severity of its impact can vary, although in many cases may be anticipated or estimated.

Hazards are defined as threats to a system, comprised of perturbations and stress (and stressors), and the consequences they produce. A perturbation is a major spike in pressure (e.g., a tidal wave or hurricane) beyond the normal range of variability in which the system operates. Perturbations commonly originate beyond the system or location in question.

Stress is a continuous or slowly increasing pressure (e.g., soil degradation), commonly within the range of normal variability. Stress often originates and stressors (the source of stress) often reside within the system.

Risk is the probability and magnitude of consequences after a hazard (perturbation or stress). 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 characterized by its location, intensity, frequency and probability. Natural hazard: the probability of occurrence, within a specific period of time in a given area, of a potentially damaging natural phenomenon. In general, the concept of hazard is now used to refer to latent danger or an external risk factor of a system or exposed subject. Hazard can be expressed mathematically as the probability of occurrence of an event of certain intensity, in a specific site and during a determined period of exposure time. A hazard, in the broadest term, is a threat to people and the things they value.

Hazards have a potentiality to them (they could happen), but they also include the actual impact of an event on people or places. Hazards arise from the interaction between social, technological, and natural systems. A rare or extreme natural or human made event that threatens to adversely affect human life, property or activity to the extent of causing disaster. A hazard is a natural or human-made phenomenon which may cause physical damage, economic losses, or threaten human life and well-being if it occurs in an area of human settlement, agricultural, or industrial activity. Note, however, that in engineering, the term is used in a more specific, mathematical sense to mean the probability of the occurrence, within a specified period of time and a given area, of a particular, potentially damaging phenomenon of a given severity or intensity. Human-Made hazard A condition which may have disastrous consequences for a society. It derives from technological processes, human interactions with the environments, or relationships within and between communities. A disasters or emergency situation in which the major direct cause or causes are intentional or unintentional human actions that result in civilian populations suffering casualties, loss of property, basic services, and means of livelihood as a result of war or civil strife. Human-made disasters or emergencies can be rapid or of slow onset and, in the case of internal conflict, lead to complex disasters. Human-made disaster acknowledges that all disasters are caused by humans because they have chosen, for whatever reason, to be where natural phenomena occurs that result in adverse impacts of people. Natural Hazard Natural phenomena which occur in proximity and pose a threat to people, structures or economic assets and may cause disaster. They are caused by biological, geological, seismic, hydrologic, or meteorological conditions or processes in the natural environment. Hazard analysis Identification, studies and monitoring of any hazard to determine its potential, origin, characteristics and behavior. The process of quantifying the probability that something will injure or harm something in a given geographic area during a specified time interval. Hazard analysis is comprised of three sequential components: hazard identification, vulnerability assessment, and risk analysis.

Hazard Assessment (also called Hazard Analysis or Evaluation) An estimate of the range of the threat from natural and technological hazards to humans and their welfare. The physical parameters used to characterize the earthquake threat include: magnitude, frequency, duration, two-dimensional areal extent, speed of onset, three-dimensional spatial dispersion, and temporal spacing (e.g., the tendency of large-magnitude earthquakes to cluster in time). The process of estimating, for defined areas, the probabilities of the occurrence of potentially-damaging phenomena of given magnitudes within a specified period of time. Hazard assessment involves analysis of formal and informal historical records, and skilled interpretation of existing topographical, geological, geomorphologic, hydrological and land-use maps, as well as analysis of social and economic and political conditions.

Hazard environment The geologic, geophysical, and geotechnical setting of the community that controls where, why, and how frequently earthquakes occur, how big they are, and their severity.

Hazard mapping The process of establishing geographically where and to what extent particular phenomena are likely to pose a threat to people, property, infrastructure, and economic activities. Hazard mapping represents the results of hazard assessment on a map, showing the frequency/probability of occurrences of various magnitudes or durations.

Hazard mitigation Sustained act¬ions taken to reduce or eliminate the long-term risk to human life and property from hazards and their effects. The term is sometimes used in a stricter sense to mean cost-effective measures to reduce the potential for damage to a facility or facilities from a disaster event.

Hazard resistant standards Guidelines for building construction that ensure a minimum level of safety for the occupants, given the forces that natural hazards impose on the area governed by the guidelines.

Hazard risk The probability that a hazard event will occur within a specified time interval; the third and highest level of hazard analysis sophistication.

Hazard vulnerability analysis An analysis that estimates the potential impact of the hazards on an area. The goal of the analysis is to prioritize potential disasters that could affect an area based on likelihood of occurrence and impact. The analysis can then be used as a starting point for emergency plans, enabling communities to use their resources most effectively.

Incident command system (ICS) A standardized on-scene emergency management construct specifically designed to provide for the adoption of an integrated organizational structure that reflects the complexity and demands of single or multiple incidents, without being hindered by jurisdictional boundaries. ICS is the combination of facilities, equipment, personnel, pro¬cedures, and communications operating with a common organizational structure, designed to aid in the management of resources during incidents. ICS is used by various jurisdictions and functional agencies, both public and private, or organized field-level incident management operations. An organizational structure used to command, control, and coordinate the use of resources and personnel that have responded to the scene of an emergency. The concepts and principles for ICS include common terminology, modular organization, integrated communication, unified command structure, consolidated action plan, manageable span of control, designated incident facilities, and comprehensive resource management. A temporary enabling bureaucracy for managing emergencies or disasters to prevent the occurrence of additional threats to the community and to responders.

Incident commander The individual responsible for the management of all incident activities, including the development of strategies and tactics and the ordering and release of resources. The IC has overall authority and responsibility for conducting incident operations and is responsible for the management of all incident operations at the incident site.

Industrial preparedness planning Actions to ensure industrial resources are available and capable of satisfying surge and mobilization requirements. Industrial Preparedness Program Plans, actions, or measures for the transformation of the industrial base, both government-owned and civilian-owned, from its peacetime activity to the emergency program necessary to support the national military objectives. It includes industrial preparedness measures such as modernization, expansion, and preservation of the production facilities and contributory items and services for planning with industry.

Landslide A massive and more or less rapid sliding down of soil and rock, causing damage in its path. The most common and wide spread type of ground failure; consists of falls, topples, slides, spreads, and flows of soil and/or rock on unstable slopes Liquefaction Occurs mainly in young, shallow, loosely compacted, water saturated sand and gravel deposits when subjected to ground shaking; results in a temporary loss of bearing strength.

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.

Magnitude a numerical quantity, devised by the late American Professor, Charles F. Richter, in the 1930’s and denoted by Arabic integers with one decimal place accuracy (for example 7.8) to characterize earthquakes in terms of the total energy released after adjusting for difference in epicentral distance and focal depth. Magnitude differs from intensity in that magnitude is determined on the basis of instrumental records; whereas, intensity is determined on the basis of subjective observations of the damage. Measured on a logarithmic scale, magnitude is open ended theoretically, with the two largest magnitude earthquakes to date being the M 9.5 Chile earthquake of 1960 and the M 9.2 Alaska earthquake of 1964. Moderate-magnitude earthquakes have magnitudes of 5.5 to 6.9; large-magnitude earthquakes have magnitudes of 7.0 to7.9; and great-magnitude earthquakes have magnitudes of 8.0 and greater. The energy increases exponentially with magnitude. For example, a magnitude 6.0 earthquake releases 31.5 times more energy than a magnitude 5.0 earthquake, but (31.5) (31.5) or approximately 1,000 times more energy than a magnitude 4.0 earthquake. Magnitude of earthquake the “size” of an earthquake, expressing the amount of energy released in the form of elastic waves as measured by a seismograph, on a scale such as Richter’s.

Man-made disaster a disaster caused not by natural phenomena, but by man’s or society’s action, involuntary or voluntary, sudden or slow, directly or indirectly, with grave consequences to the population and the environment. Examples: technological disaster, toxicological disaster, desertification, environmental pollution, conflict, epidemics, fires. A disaster that humans clearly cause, such as wars, armed conflicts, or civil strife. All other disasters, with the exception of technological disasters (e.g., industrial accidents, railway crashes) are labeled natural. Avalanches, floods, landslides, droughts, and crop failures are thus given the same quality of naturalness as earthquakes, tropical cyclones, and volcanic eruptions.

Mass casualty The definition of disaster implies a discrepancy between number of victims and its treatment capacity. This does not necessarily means a mass casualty situation, in which case the number of victims is overwhelming.

Mass casualty event Pertaining to any large number of casualties produced in a relatively short period of time, usually as the result of a single incident such as a military aircraft accident, hurricane, flood, earthquake, or armed attack that exceeds local logistical support capabilities, as in a mass casualty incident. May have the same magnitude in terms of human life and suffering, but does not destroy the infrastructure of the society. Examples of mass casualty events include epidemics, complex human emergencies, etc. The impact of such events is close to or even may exceed that of disasters, but the infrastructure remains intact and mechanisms can be developed within the infrastructure to cope with the circumstances.

Medical disaster The result of a vast ecological breakdown in the relationships between man and his environment, a serious and sudden (or slow, as in drought) disruption on such a scale that the stricken community needs extraordinary efforts to cope with it, often with outside help or international aid.”(3) This definition also indicates that it is the impact on society that constitutes the disaster, not the event that is the disaster. The most common medical definition of a disaster used is an event that results in casualties that overwhelm the health-care system in which the event occurs. A health disaster often is considered a medical disaster. However, a health disaster infers impaired public health (see Basic Functions, page ) while a medical disaster is related to the health care or break in health care to individuals (see page ) resulting from the event. The Task Force broadened this definition to: Any event that results in a precipitous or gradual decline in the overall health status of a community with which it is unable to cope adequately.

Medical Disaster Preparedness The medical preparedness in the chain of medical care is determined by personnel, materials, and methods. With the aid of this basic concept medical disaster preparedness can be expressed in a figure ranging from 1 to 5.

Mitigation Structural and non-structural measures undertaken to limit the adverse impact of natural hazards, environmental degradation and technological hazards. A range of policy, legislative mandates, professional practices, and social adjustments that are designed to reduce or minimize the effects of earthquakes and other natural hazards on a community. Mitigation measures implemented over the last 20 years have included:

  • 1) land use planning and management,
  • 2) engineering codes, standards and practices,
  • 3) control and protection works,
  • 4) prediction, forecasts, warning, and planning,
  • 5) recovery, reconstruction, and planning, and
  • 6) insurance.

Structural (e.g. reinforcing buildings) or non-structural (e.g. training building contractors or educating the public) measures taken in advance of a disaster, which are aimed at decreasing or eliminating its impact on society and environment. Activities designed to reduce or eliminate risks to people or property or to lessen the actual or potential effects or consequences of an incident. Mitigations may be implemented prior to, during, or after an incident. Mitigation measures are often developed in accordance with lessons learned from prior incidents. Mitigation involves ongoing actions to reduce exposure to, probability of, or potential loss from, hazards. Measures may include zoning and building codes, floodplain buyouts, and analysis of hazard-related data to determine where it is safe to build or locate temporary facilities. Mitigation can include efforts to educate governments, businesses, and the public on measures they can take to reduce loss and injury. 2. The totality of measures undertaken at a time distant from an actual disaster situation to permanently prevent or reduce future disaster impact (e.g., building codes and land-use regulations).

Multi-sectoral disaster risk reduction platform A nationally-owned and led mechanism—adopting the form of a forum or committee—that serves as advocate for disaster risk reduction at different levels and contributes with both analysis and advice on action through a coordinated and participatory process. A forum to facilitate the interaction of key development players from line ministries, disaster management authorities, academia, civil society and other sectors around the disaster reduction agenda. Mandatory evacuation An evacuation that takes place when appropriate authorities determine that there is an absolute need to evacuate an area, usually on a large-scale, possibly for a long period of time (for greater than twenty-four hours).

Mass casualty incident (MCI) A situation in which large numbers of casualties or patients result from a disaster such as a natural event or an act of terrorism. Mass casualty incidents potentially create a massive influx of patients to hospitals and other health care facilities.

Medical and health incident management system An overarching system for organizing and managing the medical and public health entities involved in a mass casualty incident response. The model provides an approach for a community to use in developing its own medical response capability.

Mitigation evaluation The identification of mitigation alternatives to assess the effectiveness of the alternatives. The alternatives are evaluated for their likely effect on risk and their cost. Multi-agency coordination entity An entity that functions within a broader multi-agency coordination system. It may establish priorities among incidents and associated resource allocations, untangle conflicting agency policies, and provide strategic guidance and direction to support incident management activities.

National Warning System The federal portion of the civil defense warning system, used to disseminate warning and other emergency information from the warning centers or regions to warning points in each state.

Natural hazard A naturally-occurring phenomenon that puts life or property at risk. 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. Natural Disaster a sudden major upheaval of nature, causing extensive destruction, death and suffering among the stricken community, and which is not due to man’s action.


(a) some natural disasters can be of slow origin, e.g. drought, and

(b) a seemingly natural disaster can be caused or aggravated by man’s action, e.g. desertification through excessive land use and deforestation. a potential threat to humans and their welfare caused by rapid and slow onset events having atmospheric, geologic, and hydrologic origins on solar, global, regional, national, and local scales (e.g., floods, severe storms, earthquakes, landslides, volcanic eruptions, wild fires, tsunamis, droughts, winter storms, coastal erosion, and space weather).

The probability of occurrence, within a specific period of time in a given area, of a potentially damaging phenomenon of nature. 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. 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 behavior contribute to promoting a “culture of prevention”. The aggregate of approaches and measures taken to ensure that human actions or natural phenomena DO NOT cause or result in the occurrence of an event related to the identified or unidentified hazard.(Gunn) It does not mean decreasing the severity or intensity of the event. Primary prevention of disaster is possible through technical, organizational and judicial means. Secondary prevention implies the optimal management of disaster itself. Tertiary prevention combats the complications of disaster. The better secondary prevention, the less tertiary prevention is needed. Actions taken to avoid an incident or to intervene to stop an incident from occurring. Prevention involves actions taken to protect lives and property. It involves applying intelligence and other information to a range of activities that may include such countermeasures as deterrence operations;

1. heightened inspections; improved surveillance and security operations; investigations to determine the full nature and source of the threat; public health and agricultural surveillance and testing processes; immunizations, isolation, or quarantine, and as appropriate, specific law enforcement operations aimed at deterring, preempting, interdicting, or disrupting illegal activity and apprehending potential perpetrators and bringing them to justice.

2. Activities that provide outright avoidance of the adverse impact of hazards and related disasters.

3. Activities undertaken by the first-responder community during the early stages of an incident to reduce the likelihood or consequences of threatened or actual terrorist attacks.

4. In public health, actions aimed at eradicating, eliminating, or minimizing the impact of disease and disability, or if none of these is feasible, retarding the progress of disease and disability.

The concept of prevention is best defined in the context of levels, traditionally called primary, secondary, and tertiary prevention.

Primary prevention is prevention of the occurrence of death, injury, or illness in a disaster (e.g., evacuation of a community in a flood-prone area, sensitizing warning systems for tornadoes and severe storms).

Secondary prevention mitigates the health consequences of disasters. Examples include the use of carbon monoxide detectors when operating gasoline-powered generators after the loss of electric power, employing appropriate occupant behavior in multi-story structures during earthquakes, and building “safe rooms” in dwellings located in tornado- prone areas. Secondary prevention may be instituted when disasters are imminent. Tertiary prevention is the minimization of the effects of disease and disability among those with pre-existing health conditions.

Tertiary prevention shields people with health conditions from negative health effects relating to a disaster. Examples of tertiary prevention include protecting people with respiratory illnesses and those prone to respiratory conditions from the haze and smoke that originates from forest fires and sheltering elderly who are prone to heat illnesses during episodes of extreme ambient temperatures.

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. The range of deliberate, critical tasks and activities necessary to build, sustain, and improve the operational capability to prevent, protect against, respond to, and recover from domestic incidents. Preparedness is a continuous process involving efforts at all levels of government and between government and private-sector and nongovernmental organizations

1. to identify threats, determine vulnerabilities, and identify required resources.

2. The existence of plans, procedures, policies, training, and equipment necessary at the federal, state, and local levels to strengthen the ability to prevent, respond to, and recover from major events. The term “readiness” is used interchangeably with preparedness.

3. All measures and policies taken before an event occurs that allow for prevention, mitigation, and readiness. Preparedness includes designing warning systems, planning for evacuation and relocation, storing food and water, building temporary shelter, devising management strate¬gies, and holding disaster drills and exercises.

Prevention Encompasses activities designed to provide permanent protection from disasters, including engineering and other physical protective measures, but also legislation on land use and urban planning.

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.

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.

1. The long-term activities beyond the initial crisis period and emergency response phase of disaster operations that focus on returning all systems in the community to a normal status or to reconstitute these systems to a new condition that is less vulnerable.

2. The totality of post-response measures undertaken to restore normalcy (e.g., rebuilding homes and reopening local businesses).

3. All types of emergency actions dedicated to the continued protection of the public or to promoting the resumption of normal activities in the affected area.

4. The development, coordination, and execution of service- and site-restoration plans for impacted communities and the reconstitution of government operations and services through individual, private-sector, nongovernmental, and public assistance programs that: identify needs and define resources; provide housing and promote restoration; address long-term care and treatment of affected people; implement additional measures for community restoration; incorporate mitigation measures and techniques, as feasible; evaluate the incident to identify lessons learned, and develop initiatives to mitigate the effects of future incidents.

Reconstruction Actions taken to re-establish a community after a period of rehabilitation following a disaster. Actions include construction of permanent housing, full restoration of all services, and complete resumption of the pre-disaster state.

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.

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.

Rehabilitation The operations and decisions taken after a disaster with a view to restoring a stricken community to its former living conditions, whilst encouraging and facilitating the necessary adjustments to the changes caused by the disaster.

Reconstruction Actions taken to re-establish a community after a period of rehabilitation following a disaster. Actions include construction of permanent housing, full restoration of all services, and complete resumption of the pre-disaster state. A long-term development project that follows a disaster or emergency that reconstructs a communitys infrastructure to pre-existing levels. Reconstruction is often associated with an opportunity to improve a community rather than to simply “reconstruct” a pre-existing system.

Rescue To access, stabilize, and evacuate distressed or injured individuals by whatever means necessary to ensure their timely transfer to appropriate care or to a place of safety.

Resilience The degree to which a community can recover successfully (“bounce back”) from loss and damage related to disaster impact. Elements of community resilience include the totality of measure undertaken by communities in anticipation of disaster (i.e., disaster preparedness measures). The concept of resilience has been used to characterize a system’s ability to bounce back to a reference state after a disturbance and the capacity of a system to maintain certain structures and functions despite disturbance. Resilience of the system is often evaluated in terms of the amount of change a given system can undergo (e.g., how much disturbance or stress it can handle) and still remain within the set of natural or desirable states (i.e., remain within the same ‘configuration’ of states, rather than maintain a single state). The ability of an organization to absorb the impact of a business interruption, and continue to provide a minimum acceptable level of service. Details of Resilience might be inherently unknowable – especially in the case of complex communities undergoing constant change. 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 and improving risk-reduction measures. Resilience is the flip side of vulnerability ─ a resilient system or population is not sensitive to climate variability and change and has the capacity to adapt. Not just the absence of vulnerability. Rather it is the capacity, in the first place, to prevent or mitigate losses and then, secondly, if damage does occur to maintain normal living conditions as far as possible, and thirdly, to manage recovery from the impact. Resilience is a measure of the recovery time of a system. The capacity of a group or organization to withstand loss or damage or to recover from the impact of an emergency or disaster. The higher the resilience, the less likely damage may be, and the faster and more effective recovery is likely to be. The ability to resist downward pressures and to recover from a shock. From the ecology literature: property that allows a system to absorb and use (even benefit from) change. Where resilience is high, it requires a major disturbance to overcome the limits to qualitative change in a system and allow it to be transformed rapidly into another condition. From the sociology literature: ability to exploit opportunities, and resist and recover from negative shocks. The capacity that people or groups may possess to withstand or recover from emergencies and which can stand as a counterbalance to vulnerability. Resilience is a measure of the recovery time of a system. The capacity that people or groups may possess to withstand or recover from emergencies and which can stand as a counterbalance to vulnerability. A measure of how quickly a system recovers from failures. Resiliency to disasters means a locale can withstand an extreme natural event with a tolerable level of losses. It takes mitigation actions consistent with achieving that level of protection. Resiliency is thought of as a characteristic of systems that offers flexibility and scope for adaptation whilst maintaining certain core functions (for example, access to basic needs and social stability. Pliability, flexibility, or elasticity to absorb the event. Resiliency is offered by types of construction, barriers, composition of the land (geological base), geography, bomb shelters, location of dwelling, etc. As resiliency increases, so does the absorbing capacity of the society and/or the environment.

Resiliency is the inverse of vulnerability. Qualities of people, communities, agencies, infrastructure that reduce vulnerability. Not just the absence of vulnerability rather the capacity to

  • 1) prevent, mitigate losses and then if damage occurs
  • 2) to maintain normal living conditions and to
  • 3) manage recovery from the impact.

Response The totality of measures undertaken during and immediately after disaster impact to resolve to the degree possible crisis-time problems (e.g., damage assessment, debris removal, search and rescue efforts, and emergency medical services). 2. Those activities that address the short-term, direct effects of an incident. Response includes immediate actions to save lives, protect property, and meet basic human needs. It also includes the execution of emergency operations plans, as well as mitigation activities designed to limit the loss of life, personal injury, property damage, and other unfavorable outcomes. As indicated by the situation, response activities include: applying intelligence and other information to lessen the effects or consequences of an incident; increased security operations; continuing investigations into the nature and source of the threat; ongoing public health and agricultural surveillance and testing processes; immunizations, isolation, or quarantine, and specific law enforcement operations aimed at preempting, interdicting, or disrupting illegal activity, and apprehending actual perpetrators and bringing them to justice.

Response time The time lapse between when an emergency response unit is dispatched and arrives at the scene of the emergency. Retrofitting 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.

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. A measure of the probability of damage to life, property, or the environment, which could occur if a hazard manifests itself, including the anticipated severity of consequences to people.

Risk is the product of hazard (H) and vulnerability (V) as they affect a series of elements (E) comprising the population, properties, economic activities, public services, and so on, under the threat of disaster in a given area. Risk is estimated by combining the probability of events and the consequences (usually conceptualized as losses) that would arise if the events take place. The risk formula is: Risk = Hazard * Vulnerability divided by Disaster Management, where risk is defined as the scope of consequences (loss of life, damage to property or the environment); hazard as the “Punch of Nature” (external forces); vulnerability as the weakness or strength of the element at risk, and disaster management as a comprehensive strategy based on a set of activities to reduce the risk by: reduction of the vulnerability of the elements at risk; ensuring that adequate measures are implemented before disaster strikes; responding as efficiently and effectively as possible to disasters when they occur, and assuring a sustainable development of the region stricken. Insurance is purchased to cover such exigencies. The expected number of lives lost, persons injured, damage to property and disruption of economic activities due to a particular natural phenomenon, and consequently the product of specific risk and element at risk.

Specific risk: The expected degree of loss due to a particular natural phenomenon and as a function of both, natural hazard and vulnerability. H (hazard) + V (vulnerability) = R (risk) (speeding minibus taxi) + (elderly frail woman) = (risk of accident) The probability of exposure to an event, which can occur with varying severity at different geographical scales, suddenly and expectedly or gradually and predictably, and to the degree of exposure. The probability of harmful consequences or expected losses resulting from a given hazard to a given element at danger or peril over a specified time period. In general, “risk” is defined as the expectation value of losses (deaths, injuries, property, etc.) that would be caused by a hazard. Disaster risk can be seen as a function of the hazard, exposure and vulnerability as follows;

Disaster Risk = function (Hazard, Exposure, Vulnerability). Risk can be defined as the likelihood, or more formally the probability, that a particular level of loss will be sustained by a given series of elements as a result of a given level of hazard. The elements at risk consists of populations, communities , the built environment, the natural environment, economic activities and services, which are under threat of disaster in a given area. (In this definition risk and hazard are used as synonyms) Risk is characterized by a known or unknown probability distribution of events. These events are themselves characterized by their magnitude (including size and spread), their frequency and duration, and their history. The expected number of lives lost, persons injured, damage to property and disruption of economic activity due to a particular natural phenomenon, and consequently the product of specific risk and elements at risk. The capacity of a system, community or society to resist or to change in order that it may obtain an acceptable level in functioning and structure. This is determined by the degree to which the social system is capable of organising itself, and the ability to increase its capacity for learning and adaptation, including the capacity to recover from a disaster. Risk is when you know the possible range of things that may happen following a choice; uncertainty is when you don’t. . ..Risk in its general form is when it is possible, at least in principle, to estimate the likelihood that an event (or set of events) will occur; the specific forms of those estimates are the probabilities of adverse consequences.”

Potential for exposure to loss. Risks, either man-made or natural, are constant. The potential is usually measured by its probability in years. Risk is the probability of an event multiplied by the consequences if the event occurs. A combination of the probability or frequency of occurrence of a defined hazard and the magnitude of the consequences of the occurrence. More specific, a risk is defined as the probability of harmful consequences, or expected loss (of lives, people, injured, property, livelihoods, economic activity disrupted or environment damaged) resulting from interactions between natural or human induced hazards.

The following formula is used to calculate disaster risk: Disaster Risk = Hazard x Vulnerability In this equation risk is the product of the two factors, hazard and vulnerability. Therefore, it is clear that a risk exists only if there is vulnerability to the hazard posed by a natural event. The objective (mathematical) or subjective (inductive) probability that the hazard will become an event. Factors (risk factors) can be identified that modify this probability. Such risk factors are constituted by personal behaviors, life-styles, cultures, environmental factors, and inherited characteristics that are known to be associated with health-related questions. Risk is the probability of loss to the elements at risk as the result of the occurrence, physical and societal consequences of a natural or technological hazard, and the mitigation and preparedness measures in place in the community. Risk is the expected number of lives lost, persons injured, damage to property and disruption of economic activity due to a particular natural phenomenon, and consequently the product of specific risk and elements at risk. The chance of something happening that will have an impact upon objectives. It is measured in terms of consequences and likelihood.

In disaster risk management – a concept used to describe the likelihood of harmful consequences arising from the interaction of hazards, communities and the environment.

Risk indicates the degree of potential losses in urban places due to their exposure to hazards and can be thought of as a product of the probability of hazards occurrence and the degree of vulnerability. Risk of a system may be defined simply as the possibility of an adverse and unwanted event. Risk may be due solely to physical phenomenon such as health hazards or to the interaction between man-made systems and natural events, e.g. a flood loss due to an overtopped levee. Engineering risk for water resources systems in general has also been described in terms of a figure of merit which is a function of performance indices, say for example, reliability, incident period, and reparability Risk is an integral part of life. Indeed, the Chinese word for risk “weij-ji” combines the characters meaning ‘opportunity/chance’ and ‘danger’ to imply that uncertainty always involves some balance between profit and loss.

Since risk cannot be completely eliminated, the only option is to manage it. Risk’ is the probability of a loss, and this depends on three elements, hazard, vulnerability, and exposure. If any of these three elements in risk increases or decreases, then the risk increases or decreases respectively. The risk associated with flood disaster for any region is a product of both the region’s exposure to the hazard (natural event) and the vulnerability of objects (society) to the hazard. It suggests that three main factors contribute to a region’s flood disaster risk: hazard, exposure, and vulnerability. Risk is defined as the expected losses (lives lost, persons injured, damage to property, and disruption of economic activity or livelihood) caused by a particular phenomenon. Risk is a function of the probability of particular occurrences and the losses each would cause. Other analysts use the term to mean the probability of a disaster occurring and resulting in a particular level of loss. A societal element is said to be ‘at-risk’ or ‘vulnerable’, when it is exposed to known hazards and is likely to be adversely affected by the impact of those hazards if and when they occur. The communities, structures, services, or activities concerned are described as “elements at risk.”

Risk, acceptable The concept of Acceptable Risk is not particular easy to define. It is essentially a measure of the risk of harm, injury or disease arising from a chemical or process that will be tolerated by a person or group. Whether a risk is “acceptable” will depend upon the advantages that the person or group perceives to be obtainable in return for taking the risk, whether they accept whatever scientific and other advice is offered about the magnitude of the risk, and numerous other factors, both political and social. Degree of human and material loss that is perceived by the community or relevant authorities as tolerable in actions to minimize disaster risk. Degree of humans and material loss that is perceived as tolerable in actions to minimize disaster risk”. One definition of acceptable risk that has been widely accepted in environmental regulation, although is not relevant to microbiological parameters, is if lifetime exposure to a substance increases a person’s chance of developing cancer by one chance in a million or less. This approach to determining acceptable risk is based on what is acceptable to the general public. In other words, a risk is acceptable when it is acceptable to the general public. The probability of occurrences of physical, social, or economic consequences of an earthquake that is considered by authorities to be sufficiently low in comparison with the risks from other natural or technological hazards that these occurrences are accepted as realistic reference points for determining design requirements for structures, or for taking social, political, legal, and economic actions in the community to protect people and property. Seismic risk consists of the components seismic hazard, seismic vulnerability, and value of elements at risk (both, in human and economic terms).

Risk assessment/analysis A methodology to determine the nature and extent of risk by analyzing 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. Risk analysis is the most sophisticated level of hazard analysis/assessment. It involves making quantitative estimates of the damage, injuries, and costs likely to be experienced within a specified geographic area over a specific period of time.

Risk, therefore, has two measurable components:

  • 1. the magnitude of the harm that may result (defined through vulnerability assessment)
  • 2. the likelihood or probability of the harm occurring in any particular location within any specified period of time
  • (risk = magnitude x probability).

A comprehensive risk analysis includes a full probability assessment of various levels of the hazard as well as probability assessments of impacts on structures and populations. Risk analysis is a process of determining the nature and scale of losses and damage due to disaster which can be anticipated in particular areas during a specified time period. Evaluation of risk is the social and political judgement of various risks by the individuals and communities that face them. This involves trading off perceived risks against potential benefits and also includes balancing scientific judgments against other factors and beliefs. A qualitative or quantitative (or both) determination of the likelihood of an adverse event occurring and the severity or impact of its consequences. It may include scenarios under which two or more risks interact, creating greater or lesser impacts, as well as the ranking of risky events. An objective scientific assessment of the chance of loss or adverse consequences when physical and social elements are exposed to potentially harmful natural and technological hazards. The endpoints or consequences depend on the hazard and include: damage, loss of economic value, loss of function, loss of natural resources, loss of ecological systems, environmental impact, and deterioration of health, mortality, and morbidity.

Risk assessments integrate hazard assessments with the vulnerability of the exposed elements at risk to seek reliable answers to the following questions:

  • 1. What can happen?
  • 2. How likely are each of the possible outcomes?
  • 3. When the possible outcomes happen, what are the likely consequences and losses?

Risk characterization The synthesis and summary of information about a potentially hazardous situation that addresses the needs and interests of decision makers and of all interested and affected parties. The designation of risk on a categorical scale (e.g., low, medium, and high). Risk characterization provides input for deciding which areas are most suited to mitigate risk. The chance of something happening that will have an impact on objectives. A risk is often specified in terms of an event or circumstance and the Consequences that may flow from it. Risk is measured in terms of a combination of the consequences of an event and their likelihood .

Risk communication The understanding of risks, the transfer of risk information to the public, and the transfer of information from the public to decision makers. Risk communication involves a dialogue among interested parties including risk experts, policy makers, and affected citizens.

Risk factor A characteristic that has been statistically demonstrated to be associated with (although not necessarily the direct cause of) a particular injury. Risk factors can be used for targeting preventative efforts at groups who may be particularly in danger of injury.

Risk Management The public process of deciding what to do when risk assessments indicate that risk, or the chance of loss, exists. Risk management encompasses choices and actions for communities and individuals (i.e., prevention, mitigation, preparedness, recovery) which are designed to:

  • a) stop increasing the risk to future elements that will be placed at risk to natural and technological hazards,
  • b) start decreasing the risk to existing elements already at risk
  • c) continue planning ways to respond toand recover

from the inevitable natural and technological hazard, including the imponderable extreme situation or catastrophic event. The process whereby decisions are made and actions implemented to eliminate or reduce the effects of identified hazards. A framework for the systematic application of management policies, procedures, and practices to the tasks of identifying, analyzing, evaluating, treating, and monitoring risk.

Risk mitigation The implementation of mitigating actions, depending on an organization’s chosen action posture (i.e., the decision on what to do about overall risk). Specifically, risk mitigation may involve risk acceptance (taking no action), risk avoidance (taking actions to avoid activities that involve risk), risk reduction (taking actions to reduce the likelihood and/or impact of risk), and risk sharing (taking actions to reduce risk by sharing risk with other entities). Risk mitigation is best framed within an integrated systems approach that encompasses action in all organizational areas; including personnel, processes, technology, infrastructure, and governance. An integrated systems approach helps to ensure that taking action in one or more areas will not create unintended consequences in another area.

Risk map cartographic representation of the types and degrees of hazards and of natural phenomena that may cause or contribute to a disaster.

Risk Mapping The presentation of the results of risk assessment on a map, showing the levels of expected losses which can be anticipated in specific areas, during a particular time period, as a result of particular disaster hazards. Risk Marker an attribute of the hazard that is associated with an increased probability that an event may occur and can be used as an indicator of an increased or increasing risk that the event will occur.

Risk reduction Long-term measures to reduce the scale and/or the duration of adverse effects of unavoidable or unpreventable disaster hazards on a society which is at risk, by reducing the vulnerability of its people, structures, services, and economic activities to the impact of known disaster hazards. Typical risk reduction measures include improved building standards, flood plain zoning, and land-use planning, crop diversification, and planting windbreaks. The measures are frequently subdivided into structural and non-structural, active, and passive measures. Seismic zonation a public policy tool to link earthquake risk assessment and earthquake risk management, with the objective being to identify, delineate, and highlight those geographic areas of a community where investments in expanded risk assessment and specific mitigation measures and regulations are needed to mitigate, prevent, or reduce the community’s perceived unacceptable risk.

When fully implemented, seismic zonation is the link between earthquake risk assessment and earthquake risk management. It requires three kinds of activities that build upon the current state-of-the-art and the continually evolving understanding of science, technology, and public policy. They are:

1. Development of hazards maps for use in a risk assessment. These maps characterize aspects of the hazard environment that contribute to the risk. They are constructed by integrating information and databases on the characteristics of the earthquake source, regional seismic wave propagation paths, and the local site. The maps are typically based on probabilistic concepts and depict the hazards of ground shaking, ground failure, surface fault rupture, regional tectonic deformation, and tsunami wave run up, and the aftershock sequence during a specified exposure time.

Simultaneously with the development of hazards maps, information on the perceived vulnerabilities and expected performance of the community’s built environment in a damaging earthquake is integrated and formatted for use in a risk assessment.

Applications of information management techniques (i.e., GIS) and analytical models (i.e., analytical models such as HAZUS) to assess the risk to elements of the built environment exposed to the earthquake hazards of ground shaking, ground failure, surface fault rupture, regional tectonic deformation, tsunami wave run up, and the aftershock sequence. The products of a risk assessment include statements on the risk, which can be classified by the community policy makers and stake holders through a consensus process into two categories: acceptable risk and unacceptable risk. 3) Enactment, adoption, enforcement, and implementation of community-specific public policies and professional practices that will increase a community’s earthquake resistance and mitigate, prevent, or reduce unacceptable risk.

Seismicity earthquake activity, as measured in terms of number of events, their magnitude, distribution, and frequency.

Semi-quantitative scale A scale that quantifies the variable in a way that allows rank ordering, and possibly an approximation of magnitude, but does not allow meaningful calculations within itself, such as adding and subtracting, or multiplying and dividing by another factor.

Slow disaster disaster, usually natural, the beginnings of which are slow, sometimes imperceptible until the full effect is felt, as in poor crops leading to drought and famine. Synonym: creeping disaster.

Strategic planning Consists of preparing the organization to respond to disaster threats in locations that are not specified and not immediately threatened. A plan that addresses long-term issues such as impact of weather forecasts, time-phased resource requirements, and problems such as permanent housing for displaced disaster victims, environmental pollution, and infrastructure restoration.

Structural 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.

Susceptibility the degree of ease by which a person or a population is affected by a given phenomenon. In the context of the Guidelines, susceptibility and vulnerability will be used interchangeably.

Sustainable development Development that meets the needs of the present without compromising the ability of future generations to meet their own needs. Measures that meet the needs of the present without compromising the ability of future generations to meet their own needs. It comprises the concept of “needs”, i.e. the essential needs of the 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 supply present and the future needs.

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. Sustainable development is based on socio-cultural development, political stability and decorum, economic growth and ecosystem protection, which all relate to disaster risk reduction.

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).

Tabletop exercise An exercise that places senior staff, elected or appointed officials, or other key personnel in an informal setting to discuss simulated situations. This type of exercise is intended to stimulate discussion of various issues regarding a hypothetical situation. It can be used to assess plans, policies, and procedures, or to assess types of systems needed to guide the prevention, response to, and recovery from the defined event. Tabletop exercises typically are aimed at facilitating the understanding of concepts, identifying strengths and shortfalls, and/or achieving a change in attitude. Participants are encouraged to discuss issues in depth and develop decisions through slow-paced problem solving rather than rapid, spontaneous decision-making as occurs under actual or simulated emergency conditions.

Toxicological disaster Serious environmental pollution and illness caused by the massive accidental escape of toxic substances into the air, soil or water, and to man, animals or plants.

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. The susceptibility of the population to the type (nature) of the event. In this way, vulnerability represents the susceptibility of an individual or population to injury or contagion.

The degree of possible/potential loss to a given element at risk resulting from a given hazard at a given intensity. Thus, it is the inverse of resiliency. The conditions determined by physical, social, economic and environmental factors or processes, which increase the susceptibility of a community to the impact of hazards. Characteristic of human behavior, social, and physical environments, describing the degree of susceptibility (or resistance) to the impact of e.g. natural hazards.

Vulnerability is determined by combining hazard awareness, condition of human settlements and infrastructure, public policy and administration, and organizational strength in disaster management. Poverty is one of the main causes of vulnerability in many parts of the world. The potential loss in value of an element at risk from the occurrence and consequences of natural and technological hazards. The factors that influence vulnerability include: demographics, the age and resilience of the built environment, technology, social differentiation and diversity, regional and global economies, and political arrangements.

Vulnerability is a result of flaws in planning, sitting, design, and construction.

1. The inherent state or condition of an asset that can be exploited to cause harm.

2. The susceptibility of a population to a specific type of event.

Vulnerability is also associated with the degree of possible or potential loss from a risk that results from a hazard at a given intensity. The factors that influence vulnerability include demographics, the age and resilience of the environment, technology, social differentiation, and diversity, as well as regional and global economics and politics.The extent to which an individual, community, sub-group, structure, service, or geographic area is likely to be damaged or disrupted by the impact of a particular disaster hazard.

Vulnerability study Study and investigation of all the risks and the hazards susceptible to cause a disaster.

Vulnerability Analysis The process of estimating the vulnerability to potential disaster hazards of specified elements at risk. For engineering purposes, vulnerability analysis involves the analysis of theoretical and empirical data concerning the effects of particular phenomena on particular types of structures. For more general socio-economic purposes, it involves consideration of all significant elements in society, including physical, social and economic considerations (both short- and long-term), and the extent to which essential services and traditional and local coping mechanisms are able to continue functioning. The assessment of an exposed population’s susceptibility to the adverse health effects of a particular hazard.

Warning A message informing of danger. The alerting of emergency response personnel and the public to the threat of extraordinary danger and the related effects that specific hazards may cause. A warning issued by the National Weather Service (e.g., severe storm warning, tornado warning, tropical storm warning) for a defined area indicates that the particular type of severe weather is imminent in that area. In the military, a communication and acknowledgment of dangers implicit in a wide spectrum of activities by potential opponents ranging from routine defense measures to substantial increases in readiness and force preparedness and to acts of terrorism or political, economic, or military provocation. Also refers to operating procedures, practices, or conditions that may result in injury or death if not carefully observed or followed.

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