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.


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.

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.


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.

Risk Assessment

The process of determining the nature and extent of risk by analyzing potential hazards and evaluating existing condition of vulnerability and capacity. OR

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



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

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.


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.

Disaster Management Spiral

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

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

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


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.