Basic Definitions in Disaster Management

Disaster Risk Management

The systematic process of using administrative decisions and operational skills to implement policies and coping strategies within the communities to lessen the impacts of natural hazards. This comprises all forms of activities, including structural and nonstructural measures to avoid (prevention) or to limit (mitigation and preparedness) adverse effects of hazards. Disaster Risk Management (DRM) refers to the systematic approach of analyzing, assessing, and managing the risks associated with disasters. It involves activities and measures aimed at reducing vulnerabilities, preventing or minimizing the impact of disasters, and promoting resilience. DRM encompasses various phases, including risk assessment, mitigation, preparedness, response, and recovery.

Example: A city's disaster risk management plan includes initiatives such as early warning systems, community training programs, infrastructure improvements, and coordination mechanisms among emergency response agencies.


A serious disruption of the functioning of a community causing widespread human, material, economic or environmental losses which exceed the ability of the affected community to cope using its own resources. A disaster is a function of the risk process. It results from the combination of hazards, conditions of vulnerability and insufficient capacity or measures to reduce the potential negative consequences of risk. A disaster is a sudden event or series of events that disrupts the normal functioning of a community or society, causing significant damage, destruction, and loss of lives and livelihoods. Disasters can be natural, such as earthquakes, floods, hurricanes, or man-made, including industrial accidents, terrorist attacks, or pandemics.

Example: A severe earthquake strikes a region, resulting in collapsed buildings, infrastructure damage, and a large number of casualties, disrupting the normal life of the affected population.

According to NHRG (Natural Hazard Research Group) a disaster is an event meeting the below defined criteria:

  1. $1 Million Losses
  2. At least 100 lives lost
  3. At least 100 people injured


The probability of harmful consequences, or expected losses resulting from the interactions between hazards and vulnerable conditions e.g. deaths, injuries, property, livelihoods, economic activity disrupted or environmental damages. Risk refers to the potential for a disaster event to occur and the associated adverse consequences or impacts. It combines the probability or likelihood of an event occurring with the severity of its potential consequences. Risks are influenced by hazards, vulnerabilities, and exposure to the affected population, infrastructure, and environment.

Example: The risk of flooding in a coastal area is assessed based on factors such as historical flood data, climate patterns, topography, and the vulnerability of infrastructure and populations in flood-prone zones.


Structural and non-structural measures taken to reduce the adverse effects of a disaster, if it occurs e.g. construction of retaining walls, widening of water channels, building codes etc. Mitigation refers to the actions and measures taken to reduce or prevent the impacts of disasters. It involves identifying vulnerabilities, implementing structural and non-structural measures, and developing policies and strategies to minimize risks.

Example: Building and enforcing strict building codes and regulations in earthquake-prone areas to ensure the construction of resilient structures that can withstand seismic forces.

Risk Assessment

The process of determining the nature and extent of risk by analyzing potential hazards and evaluating existing condition of vulnerability and capacity. Risk assessment is the process of evaluating the potential risks and vulnerabilities associated with hazards. It involves analyzing the likelihood and potential consequences of specific hazard events to determine the overall risk and inform decision-making regarding disaster management strategies.

Example: Conducting a risk assessment for a region prone to hurricanes involves analyzing historical hurricane data, vulnerability of buildings and infrastructure, and the density of population in vulnerable areas.


The estimation of risk posed by a hazard. Risk assessment consists of the following steps:

  1. Hazard Assessment
  2. Vulnerability Assessment
  3. Capacity Assessment

Hazard vs Disasters

A hazard refers to a potential threat or source of danger that can lead to a disaster. Hazards can be natural, such as earthquakes, storms, or wildfires, or human-induced, such as chemical spills or industrial accidents. A disaster, on the other hand, is the actual occurrence and impact of a hazardous event that causes significant damage, loss, and disruption.

Example: An active volcano is a hazard, while an eruption that causes destruction and displacement is a disaster.


Resistance refers to the ability of a system, community, or infrastructure to withstand and resist the impact of a hazard or disaster without significant damage or disruption. It involves designing structures or implementing measures to enhance their ability to withstand extreme events.

Example: Constructing buildings with reinforced concrete and steel frames to resist the impact of strong winds during hurricanes or typhoons.


Capacity of a community to resist, absorb, adjust to and recover from the negative impacts of a disaster in a timely and efficient manner. OR

Resilience is the capacity of a system or community to adapt, recover, and bounce back from the impacts of a disaster. It involves building the ability to absorb shocks, maintain essential functions, and quickly restore normalcy.

Example: A community that, despite facing a severe flood, has the ability to quickly restore critical infrastructure, provide assistance to affected households, and recover their livelihoods demonstrates resilience.

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 e.g. risk management plans, community recovery plans, ‘culture of prevention’, early warning systems, awareness programs etc.

The strengthening of coping capacities usually builds resilience to withstand the effects of natural and human-induced hazards.

Value or Exposure

The dimension and cost of a region’s goods that might be susceptible to losses from a threat. Such exposure extends to infrastructure, the populace, economy and production. Determining the value of exposure becomes more complicated depending on the size and diversity of a region. Value or exposure refers to the extent to which people, infrastructure, assets, and natural resources are exposed and susceptible to the impacts of a hazard or disaster. It includes physical, economic, social, and environmental values at risk.

Example: A densely populated coastal city with high-value infrastructure, such as ports, airports, and industrial facilities, has a significant exposure to the impacts of a potential tsunami.


Refers to changes in natural and human systems to reduce risks to the lives and livelihoods of people. Adaptation actions can reduce many unavoidable impacts in the near term, although they cannot reduce them to zero. Failure to mitigate will eventually lead to failure of adaptation because the magnitude of the impacts is predicted to become too large to manage even with considerable investment. Adaptation and mitigation are not alternative strategies but complementary ones that need to be pursued together. Adaptation refers to the process of adjusting and modifying strategies, policies, and practices to better cope with the changing conditions and risks associated with hazards and climate change. It involves proactive measures to reduce vulnerabilities and increase resilience.

Example: Implementing climate change adaptation measures, such as modifying agricultural practices, diversifying livelihoods, and constructing flood-resistant infrastructure, to cope with changing rainfall patterns and increased flood risks.

Disaster Management Spiral

Relief ==> Recovery ==> Reconstruction ==> Prevention ==> Prepare

↓ Relief ==> Recovery ==> Reconstruction ==> Prevention ==> Prepare

↓ Relief ==> Recovery ==> Reconstruction ==> Prevention ==> Prepare

The disaster management spiral is a continuous cycle of activities that encompasses various phases of disaster management, including preparedness, response, recovery, and mitigation. It emphasizes the iterative and interconnected nature of these phases and the need for ongoing learning and improvement.

Example: After responding to a flood event, disaster management agencies engage in post-disaster recovery activities, conduct a review of the response efforts, update preparedness plans based on lessons learned, and implement mitigation measures to reduce future risks.


The conditions determined by physical, social, economic and environmental factors or processes, which increase the susceptibility of a community to the impact of hazards. OR

A set of prevailing conditions which adversely affect the community’s ability to prevent, mitigate, prepare for or respond to a hazard. Absence of coping strategies is also a part of vulnerability and has to be considered in vulnerability assessment e.g. living in hazard prone locations like near to a sea or river, above the fault lines, at the base of a mountain etc.

Vulnerability refers to the susceptibility or susceptibility of individuals, communities, or systems to the impacts of hazards and disasters. It is influenced by factors such as socio-economic conditions, infrastructure quality, access to resources, and the capacity to cope and adapt.

Example: Communities living in informal settlements with inadequate housing, limited access to basic services, and high poverty rates are often more vulnerable to the impacts of disasters compared to affluent neighborhoods with resilient infrastructure and resources.