This document provides definitions and concepts related to disasters. It defines a disaster as a serious disruption that exceeds a society's ability to cope using its own resources. Hazards are physical or human-made events that can potentially trigger a disaster. Risk is defined as expected losses from a hazard of a particular magnitude in a given area over time. Vulnerability refers to susceptibility to harm from physical, social, economic or political factors. Resilience is the ability to prevent, mitigate, prepare for, respond to and recover from disasters without compromising long-term development. The document also categorizes different types of disasters and hazards.

1. INTRODUCTION TO DISASTERS
CONCEPTS AND DEFINITIONS
Megha Bedi
Assistant Professor
Civil Engineering Department

2. TERMINOLOGIES
DISASTER
“… A SERIOUS DISRUPTION OF THE
FUNCTIONING OF A SOCIETY, CAUSING
WIDESPREAD HUMAN, MATERIAL, OR
ENVIRONMENTAL LOSSES WHICH EXCEED
THE ABILITY OF THE AFFECTED SOCIETY TO
COPE USING ITS OWN RESOURCES.”
2

3. Contd..
• The United Nations defines Disaster as “THE
OCCURRENCE OF A SUDDEN OR MAJOR
MISFORTUNE WHICH DISRUPTS THE BASIC
FAFRIC AND NORMAL FUNCTIONING OR A
SOCIETY (COMMUNITY).”

4. 4
TYPES OF DISASTERS
SUB GROUP I
WATER &
CLIMATE
RELATED
DISASTERS
FLOODS & DRAINAGE MGT.,
CYCLONES, TORNADOES &
HURRICANES, HAILSTORM,
CLOUD BURST, HEAT WAVE &
COLD WAVE, SNOW
AVALANCHES, DROUGHTS,
SEA EROSION AND
THUNDER & LIGHTNING.
SUB GROUP II
GEOLOGICALLY
RELATED
DISASTERS
LANDSLIDES, MUDFLOWS,
EARTHQUAKES, DAM
FAILURES / DAM BURSTS
AND MINE FIRES.
SUB GROUP III
CHEMICAL,
INDUS., &
NUCLEAR
RELATED
DISASTER
THE CHEMICAL AND
INDUSTRIAL & NUCLEAR
DISASTERS HAVE BEEN
INCLUDED.

5. Contd…
SUB GROUP IV ACCIDENT RELATED
DISASTERS
FOREST / URBAN
FIRES, MINE
FLOODING, OIL
SPILL, MAJOR BLDG.
COLLAPSE, SERIAL
BOMB BLASTS ETC.
SUB GROUP V BIOLOGICALLY
RELATED DISASTERS
BIOLOGICAL
DISASTER &
EPIDEMICS, PEST
ATTACKS, CATTLE
EPIDEMICS & FOOD
POISONING ETC.
5

6. HAZARD
• A Hazard is a physical or human-made event
that can potentially trigger a disaster.
• A rare or extreme natural or human- made event
that threatens to adversely affect human life,
property to the extent of causing a disaster.

7. 7
H
A
Z
A
R
D
S
VIOLENCE BASED
War, Armed
Conflict, Physical
Assaults etc.
NATURE BASED
Earthquakes,
Droughts, Floods,
Cyclones etc.
FAILING
INDUSTRIALLIZE
D SOCIETY
BASED
Fire, Gas leakage,
Transport
Collisions etc.
DETERIORATION
BASED
Environmental
Degradation,
Declining Health,
Education & other
Social services.

8. RISKS
• Risk is the measure of the expected losses due to
a hazard event of a particular magnitude
occurring in a given area over a specific time
period.
• The level of risk depends upon:
– Nature of the hazard
– Vulnerability of the affected elements
– Economic value of affected elements

9. VULNERABILITY
• Vulnerability is the
‘Susceptibility to harm’
of those at risk.
• Vulnerability may be:
– Physical
– Social
– Economic
– Political

10. RESILIENCE
• Resilience is the capacity to prevent, mitigate,
prepare for, respond to and recover from the
impacts of disasters.
• It is the ability of individuals, communities,
organizations and states to adapt to and
recover from hazards, shocks or stresses
without compromising long-term prospects
for development.

11. Core Elements of Disaster Resilience
• Context: Whose resilience is being built – such as a social group, socio-economic or
political system, environmental context or institution.
• Disturbance: What shocks (sudden events like conflict or disasters) and/or stresses
(long-term trends like resource degradation, urbanisation, or climate change) the group
aims to be resilient to.
• Capacity to respond: The ability of a system or process to deal with a shock or stress
depends on exposure (the magnitude of the shock or stress), sensitivity (the degree to
which a system will be affected by, or will respond to, a given shock or stress), and
adaptive capacity (how well it can adjust to a disturbance or moderate damage, take
advantage of opportunities and cope with the consequences of a transformation).
• Reaction: A range of responses are possible, including: bounce back better, where
capacities are enhanced, exposures are reduced, and the system is more able to deal
with future shocks and stresses; bounce back, where pre-existing conditions prevail; or
recover, but worse than before, meaning capacities are reduced. In the worst-case
scenario, the system collapses, leading to a catastrophic reduction in capacity to cope
with the future.

12. Contd…

13. THANKU…!