ENVIRONMENTAL

SCIENCE
DISASTERS
 What is Disaster?
• A disaster is “a sudden
accident or a natural
catastrophe that causes
great damage or loss of
life.”
• A DISASTER is an event
or series of events, which
give rise to casualties
and damage or loss of
property, infrastructure, or
means of livelihood.
 Disasters
• Disasters give rise to casualties and
damage or loss of property, infrastructure
or means of livelihood.
• Disasters threaten sustainable economic
development worldwide.
• In past twenty years, calamities have
killed around 3million people and made
them homelessness and misery on 1
million people.
NATURAL DISASTERS
EARTHQUAKES
• Earthquakes cause the shaking, rolling or movement of the
earths surface.
• Earthquakes happen along cracks called (fault lines)in the
earths surface.
• Earthquake is a sudden geological event below the surface of
the earth which results in generation of shock waves that
travel vertical and horizontal vibrations.
• These consequential motions cause destruction.
EARTHQUAKES-SEISMICITY IN
MAHARASHTRA
• Maharashtra occupies the central-
western portion of peninsular India. A
disastrous earthquake occurred ,at
Koyna on December 11th,1967,with a
magnitude of 6.5 on the Richter Scale.

• In Latur September,30th,1993, with a

magnitude 6.4.
EARTHQUAKES :Do’s & Don'ts
IF INDOOR : IF OUTDOORS
1.Drop to the ground, take cover 1.Stay there, until the shaking
under a table or other piece of stops.
furniture; and hold on until shaking 2.Move away from buildings,
stops.
trees, streetlights and utility wires.
2.Stay away from glass, walls, falling
3.If on a moving vehicle stop
fixtures etc.
quickly as safety permits. Avoid
3.Stay in bed when earthquake
stopping near under
strikes, hold and protect your head
with pillows. buildings ,trees and wires.
4.Use a doorway for shelter, if it is in 4.Avoid roads, bridges or ramps
close proximity. which might have been damaged
5.Be aware that electricity may go by the earthquake.
out or fire alarms may turn on. 5.Do not forget to carry disaster
6.Do not use elevators. emergency kit.
 FLOODS
A flood is an overflow of water that submerges land. Flooding
may result from the volume of water within a body of water,
such as a river or lake, which overflows or breaks its usual
boundaries. Floods have been a recurrent phenomena in India
from time immemorial.
 Flood denotes accumulation of water which results from an
imbalance between inflow and outflow of water in a river.

 Floods affect Maharashtra quite frequently. Most floods occur

during monsoon.
 Floods destroy houses, crops and food stocks.
There are three types of Floods.
 Flash floods-Flash floods occur in hilly areas, where sudden
very heavy rains cause strong flow of water. When a
temporary blockage in hilly areas impounds water, which
when released suddenly creates havoc.

 River floods- Heavy rainfall, snowmelt, and short intense

storms cause floods. Inadequate capacity within the banks of
the river to contain high flows.

 Coastal floods- are caused due to tsunami or heavy rainfall

from cyclones.
FLOODS – DO’S AND DON’TS
DO’S DON’TS
1.Turn off power and gas 1.Do not wade through flood
connection be alert for gas leaks. water.
2.Disconnect electrical 2.Do not eat food which has
appliances , do not touch them been in contact with flood water.
with wet hands. 3.Do not drink from wells, drink
3.Secure your home, move only boiled water.
essential items to an upper floor. 4.Do not use gas, electricity or
4.Stay away from electrical electrical appliances which have
ports, fallen power lines. come in contact with flood water.
5.Stay away from sewage lines, 5.Do not walk near riverbanks or
drains etc. canal edge as these may
collapse.
 CYCLONES
• Cyclones are violent rotating windstorms which occur in every
major ocean across the world.
• When a cyclone hits the coast, the accumulated mass of sea-
water strikes the coast as a giant sea wave called the storm
surge.
• Cyclones occur in the Indian Ocean; the Bay of Bengal, which
pose a major threat to life and property.
 TSUNAMIS.
• A tsunami is a series of waves with a long wavelength and
period.
• Tsunami is a Japanese word meaning ‘harbour wave”, the sea
waves generated by undersea earthquakes.
• These waves originate from under sea or coastal seismic
activity or undersea earthquake ultimately breaking over land
with great destructive power.
• Tsunami causes major destruction to the human settlements,
roads, ports and infrastructure.
TSUNAMIS – DO’S AND DON’TS.
DO’S DON’TS
1.First protect yourself.. 1.Avoid downed power
lines and stay away from
2.Do not forget to carry damaged buildings and
the disaster emergency bridges.
kit. 2.Move quickly to higher
ground away from the
coast.
 DROUGHT.
• In India, the erratic nature of monsoon, with long dry spells
and high temperature. This is mainly responsible for draught.
• The Deccan plateau constitutes 50% of the drought –prone
areas and 12% of the population lives in such areas.
• Variations of rainfall in monsoon leading to water shortage
causes drought.
DROUGHT- DO’S AND DON’TS
DO’S DON’TS

• Monitoring of rainfall on a • Do not waste water,

regular basis. especially drinking water,
• Advising farmers to take up as it is precious.
drought resistant crops and • Do not waste food , as it
crops requiring less water.
could be useful for those
• Utilizing available water
in need.
carefully.
• Implement central and
state government schemes
towards mitigating adverse
effects of drought.
QUESTIONNAIRE
1. Explain the impact of
an earthquake?
2. What are cyclones?
3. What is a Tsunami?
4. Enlist some do’s
during floods?
5. Explain the don'ts of
a Draught.
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URBAN FLOODS
• Urban areas are densely populated and people living here are
vulnerable to suffer due to floods, resulting in loss of life, loss
of livelihood and human suffering.
• Major cities in India, have witnessed loss of life and property,
disruption in transport and power and incidence of epidemics.
 TYPES OF DROUGHTS
• Meteorological Drought- referring to lack of precipitation.

• Agricultural Drought- referring to lack of moisture in the soil where

crops grow.

• Hydrological Drought- referring to low levels of water in reservoirs.

• Socio-economic Drought- referring to water shortages affecting

people in society, which impacts availability of food grains, fodder,
etc.
 VOLCANOES
• A Volcano is a rupture in the crust of a planetary mass
object, such as Earth, that allows hot lava,
volcanic ash, and gases to escape from the magma
chamber below the surface.
• Earths volcanoes occur because its crust is broken into
17 major tectonic plates that float on a hotter,
softer layer in its mantle.
• Barren Island one of the most easterly of the Andaman
and Nicobar Islands, is the only confirmed active
volcano in India.