The document discusses the nature and impact of disasters, categorizing them into natural and man-made events, highlighting various types of hazards including floods, earthquakes, and industrial accidents. It emphasizes concepts such as vulnerability, exposure, and coping capacity, as well as specific case studies and examples, particularly focusing on Tamil Nadu's multi-hazard vulnerability. Additionally, it outlines the role of the Tamil Nadu Disaster Management Authority in mitigating and managing disaster risks.

1. Unit I
HAZARDS, VULNERABILITY AND
DISASTER RISKS
Prepared by
Dr.S.Ajith
Assistant Professor – ISE

2. Disasters
Disasters are the hazards that cause destruction or
environmental changes
Types
Natural disaster
Man made disaster

3. Disaster –
General Definition
The disaster is an undesirable
occurrence of events of such
magnitude and nature that adversely
affect production, cause loss of
human lives, injuries and properties
as well as damage to the
environment.

4. Disaster –
Disaster Management Act of 2005
“Disaster means a Catastrophe, Mishap, Calamity or Grave
occurrence in any area, arising from natural or man-made
causes, or by accident or negligence which results in
substantial loss of life or human suffering or damage to, or
degradation of environment and is of such a nature or
magnitude as to be beyond the Coping Capacity of the
community of the affected area.”

5. What is Hazard ?
A process, phenomenon or Human
Activity that may cause Loss of Life,
Injury or other Health Impacts, Property
Damage, Social and Economic
Disruption or Environment Degradation
Hazards – Hazards have a potential to
cause Damages & Losses & only if they
Cause Damages & Losses, we may tag
them as Disasters & otherwise Not!

6. Case Study - Hazard
“An expert biker is riding his brand new
bike on the Mumbai -Pune Expressway. It
is the monsoons and the Western Ghats is
looking absolutely stunning. All of a
sudden, a small rock rolls down from the
steep slopes and lands right in front of the
biker. The biker, who was riding almost as
fast as the wind, could not control his bike
and skidded off the road.”

7. Vulnerability
It is the inability to resist a hazard or to respond when a disaster has occurred.
For instance, people who live on plains are more vulnerable to floods than people
who live higher up.
In actual fact, vulnerability depends on several factors, such as people's age and
state of health, local environmental and sanitary conditions, as well as on the quality
and state of local buildings and their location with respect to any hazards.

8. What human actions can increase our vulnerability?
When people cut down too many trees at a faster pace leads to
deforestation.
It increases the vulnerability of many communities to rain which,
when they fall on unprotected soil, cause mudslides, landslides,
floods and avalanches.
 Building homes in high-risk places makes more vulnerable.
 For instance, if you live too close to a river and people have been
throwing garbage into it so that the water cannot flow on through,
you will be more vulnerable to floods.

9. Exposure
The situation of people, infrastructure, housing, production capacities and other tangible human
assets located in hazard-prone areas.
How do we measure exposure?
Measures of exposure can include the number of people or types of assets in an area. Common data
sources are council and local government agencies, household surveys, aerial photos, and individual
architectural/structural drawings

10. Coping Capacity
It is the ability of people, organizations and
systems, using available skills and resources, to
manage adverse conditions, risk or disasters.
The capacity to cope requires continuing
awareness, resources and good management,
both in normal times as well as during disasters
or adverse conditions.
Coping capacities contribute to the reduction of
disaster risks.

11. Classification
of Hazards
Categorized by “High
Powered Committee” (HPC)
in August, 1999, before the
Orissa super cyclone in
November, 1999

12. Natural Disaster A natural disaster is the effect of a natural hazard (e.g., flood,
tornado, hurricane, volcanic eruption, earthquake, landslide

13. Examples of Natural Disasters
Cyclone
Earthquake
Tornado
Volcanic eruption
Tsunami
Flood
Drought
Avalanche
Landslide

14. Cyclone
 Cyclone refers to any spinning storm that rotate
around a low pressure centre
Closed low level atmospheric circulation, strong
winds and a spiral arrangement of thunderstorms
that produce a heavy rain
Cyclones are characterised by inward spiral winds
that rotate about a zone of low air pressure

15. Cyclone forms due to latent heat
driven by significant activity
The biggest cyclone recorded is
the Bhola cyclone. It hit coast of
today’s Bangladesh in 1970 with a
death of 3,00,000 people.

16. Earthquakes
Earthquake, any sudden shaking of the ground caused by
the passage of seismic waves through Earth’s rocks.
Seismic waves are produced when some form of energy
stored in Earth’s crust is suddenly released, usually when
masses of rock straining against one another suddenly
fracture and slip.
They are measured using seismograph
The Valdivia earthquake is the biggest earthquake ever
recorded. It hit Chile on May 22, 1960 with a magnitude of
9.5 Richter scale & death of around 6000

17. Tornados (Twisters)
A tornado is a violently rotating column of air that
is touching both the ground and a cumulonimbus
cloud.
Tornado conditions are caused when different
temperatures and humidity meet to form thunder
clouds
 Twisters can attain speed upto 100 miles an hour
 The deadliest tornado recorded in Daultipur and
Salturia, Bangladesh on April 26th
, 1989. Death –
1300 & injured – 12,000

18. Volcanic Eruption
A Volcano is an opening in a planet’s surface
which allows hot magma to escape from the
surface.
Study of volcano is called volcanology and
volcanic eruptions are measured using volcanic
explosivity index.
The biggest volcanic eruption is Mount Tambora,
Indonesia on April 10, 1815. Death – 71,000

19. Tsunami
A tsunami 'harbour wave’, is a series of waves in
a water body caused by the displacement of a
large volume of water, generally in an ocean or a
large lake.
The tsunami caused by 2004 in Indian ocean by
earthquake is the deadliest natural disaster with
a dead of 2,80,000

20. Floods
Floods are caused when water
overflows from a water body
One of the biggest flood in the world is
the Yellow river flood in China in 1887
which killed around 9,00,000

21. Drought
Drought is a prolonged dry period in the
natural climate cycle that can occur
anywhere in the world.
It is a slow-onset disaster characterized
by the lack of precipitation, resulting in a
water shortage.
Drought can have a serious impact on
health, agriculture, economies, energy
and the environment.

22. Avalanches
An avalanche is a rapid flow of snow down a
hill or mountainside.
Although avalanches can occur on any slope
given the right conditions, certain times of
the year and certain locations are naturally
more dangerous than others.
Wintertime, particularly from December to
April, is when most avalanches tend to
happen.
 The biggest avalanche happened in Mt.
Huascaran, Peru killing 20,000 people

23. Landslide
A landslide is the movement of rock, earth, or
debris down a sloped section of land.
Landslides are caused by rain, earthquakes,
volcanoes, or other factors that make the
slope unstable.
Geologists, scientists who study the physical
formations of the Earth, sometimes describe
landslides as one type of mass wasting.

24. Man made Disasters
Bhopal Gas Tragedy
On December 2, 1984, poisonous Methyl
Isocyanate (MIC) gas spilled from the factory
run by Union Carbide.
One of the deadliest chemical disasters in
history left over 10,000 people dead (the exact
number is still being debated) and over 5.5
lakh more injured and in excruciating pain.

25. Fire at AMRI Hospital
AMRI Hospital's basement caught fire in
the early morning hours of December in
Kolkata's Dhakuria neighbourhood.
On the morning of December 9, 2011,
most patients and medical personnel were
asleep because it was early (about 3 am).
160 stuck in the hospital 89 lost their lives in the
incident

26. Jaipur Fire (Indian Oil)
The Jaipur oil depot fire broke out on 29
October 2009 at 7:30 PM (IST) at the Indian
Oil Corporation (IOC) oil depot's giant tank
holding 8,000 kilolitres of petrol, in Sitapura
Industrial Area on the outskirts of Jaipur,
Rajasthan, killing 12 people and injuring over
300.

27. Other Industrial Accidents
May 7, 2020: Visakhapatnam gas leak. A gas leakage accident at LG Polymers chemical plant in
Gopala samudram, Vizag. The leakage had spread over a radius of about 3 km, affecting the
nearby areas and villages. 11 were killed and more than 1000 people were injured as of 7 May
2020.
3 June 2020: 2020 Dahej chemical plant explosion. Five deaths and more than fifty people
injured.
August 4, 2020: 2020 Beirut explosions (Lebonan). A massive explosion of a large cache of
ammonium nitrate at the Port of Beirut flattened much of the port and damaged buildings
throughout the city. More than 200 people were killed and over 7000 injured.

28. Other Industrial Accidents
4 November 2020: Ahmedabad chemical factory blast resulted in twelve deaths and injuries to nine
people.
6 January 2022: Surat gas leak: At least six people died and 22 people became sick following gas leak
from a tanker in an industrial area in India.
4 June 2022: 2022 Sitakunda fire. A fire and subsequent explosions at a container storage facility in
Bangladesh's Chittagong District killed at least 33 people and injured more than 450 others.
27 June 2022: 2022 Aqaba toxic gas leak, at least 10 dead and more than 251 injured by ruptured tank
containing 25 tons of chlorine in Port of Aqaba, Jordan.

29. Pandemic
Coronavirus disease (COVID-19) is an infectious disease caused by
the SARS-CoV-2 virus.
Most people infected with the virus will experience mild to moderate
respiratory illness and recover without requiring special treatment.
However, some will become seriously ill and require medical
attention. Older people and those with underlying medical
conditions like cardiovascular disease, diabetes, chronic respiratory
disease, or cancer are more likely to develop serious illness.
Anyone can get sick with COVID-19 and become seriously ill or die at
any age.

32. Disaster Vulnerability Profile of Tamilnadu
Tamil Nadu is prone to multi hazards, higher than other States and is frequented by hazards
of various nature and different intensities.
The vulnerability of the coastal community became exceedingly evident when Tsunami struck
the southern coast of India.
Besides Tsunami, the coastal community faces disasters like cyclone and floods periodically.
Communities in other hazard prone plains and hilly regions of the State face threats from
Landslides, Earthquakes and Floods. Urban flooding is also becoming a growing concern in
the State.

33. Cyclone
In general, the coastal area of Tamil Nadu is prone to cyclones and depressions. Cyclone forms in
low-pressure zones in the Bay of Bengal. The cyclone along the Tamil Nadu coasts is not as severe
as in Andhra Pradesh.
Tsunami
An earthquake of magnitude 9.00 on the Richter scale struck seabed off the Sumatra Coast,
Indonesia at 6.28 AM on 26.12.2004. The resultant seismic giant sea wave (Tsunami) battered the
coast of South India. The people living in villages and towns all along the coastline Chennai,
Kancheepuram, Tiruvallur, Villuppuram, Cuddalore, Nagapattinam, Tiruvarur, Thanjavur,
Pudukkottai, Ramanathapuram, Thoothukkudi, Tirunelveli and Kanniyakumari were affected

34. Major Cyclone in Tamilnadu

35. Tamilnadu State Disaster Management Authority
1. Hon’ble Minister for Revenue and Disaster Management
2. Chief Secretary to Government
3. Secretary, Revenue and Disaster Management Department
4. Secretary, Finance Department
5. Secretary, Home Department
6. State Relief Commissioner and Commissioner of Revenue Administration
7. Director, Centre for Disaster Management & Mitigation, Anna University, Chennai and
8. Head of Department of Civil Engineering, Indian Institute of Technology, Madras.

36. Role of TN Disaster Management Authority
The State Disaster Management Authority (SDMA) is responsible for coordinating the
response to disasters and to reduce risks.
All measures for mitigation, preparedness, response, and recovery are undertaken
under the guidance and supervision of the Authority.
The SDMA approves the State Disaster Management Plan and District Disaster
Management Plans in accordance with the guidelines laid down by the National Disaster
Management Authority.