and Jitendra Kumar
College of Fisheries, KVAFSU, Mangalore,
A natural disaster is
the effect of a natural
hazard- (e.g. flood,
landslide) that affects
the environment, and
leads to financial,
The World is always changing.
Natural disasters are changes which are
so great they may cause damage to the
shape of the land or to the lives of people
and other living things.
Great changes happen deep inside the
Earth and on its surface. The changes on
the outer part of the Earth happen
because of different kinds of weather.
Cyclone or Hurricane
Forest fire or Bushfire
A volcanic eruption is the spurting out of gases and
hot lava from an opening in the Earth’s crust.
Pressure from deep inside the Earth forces ash, gas
and molten rock to the surface.
A volcano is a mountain or hill formed by the
accumulation of magma or molten rock
Volcanoes are hazardous to wildlife and humans
1. Volcanic Gases
4. Ash Fall
an incredible surge of sulfur dioxide gas into
the stratosphere where it combined with
water to form sulfuric acid. The new aerosol
deteriorated the Earth's ozone layer by
altering the chlorine and nitrogen
But even when a volcano isn't erupting, it
emits gases from fumaroles, cracks or
openings from the ground. Most of these
gases is water vapor which combines with
carbon dioxide, sulfur dioxide, hydrogen
sulfide, hydrogen, and fluorine to produce
harmful gases such as acid rain. The extra
carbon dioxide in the air will result in animal
and human deaths
Landslides are also very common with
volcanoes. The terrible shaking of an
eruption causes the loose debris on the side
of the mountain to rapidly fall down its steep
flank. However, debris avalanches may also
be caused by earthquakes or heavy rainfall.
Mount St. Helens eruption caused the largest
volcano landslide in recorded history, while
Mount Rainier have had at least five large
avalanches within the past 6,00 years. Such
massive landslides result in a complete burial
of surrounding cities and the obliteration of
wildlife and such.
However, of all the effects of volcanoes,
mudflows or lahars are the deadliest. Debris
flows of mud, rock, and water travel down
the flank and into valleys and streams at
velocities of 20 mph to 40 mph. Some of the
most extreme cases have lahars with a
consistency of wet concrete flowing up to 50
An earthquake is a violent shaking of the ground.
Sometimes it is so strong that the ground splits
When parts of the earth, called plates, move
against each other giant shock waves move upwards
towards the surface causing the earthquake.
Earthquakes release an incredible amount of
energy and are able to destroy bridges,
buildings, and even entire cities in just a few
Below are some pictures of some of the most
destructive earthquakes in recent history.
A Cyclone is a fierce storm with storm winds
that spin around it in a giant circle. During a
cyclone trees can be uprooted, buildings
can be destroyed and cars can be
Hurricanes can combine the effects of other
natural disasters, proving especially
The monsoon is a wind current in Southern
Asia, blowing northeast during the summer
and southwest during the winter.
During the summer, the monsoon brings
heavy rains to southern Asia and Africa,
while in the winter it causes the drier
The effects of the winter monsoons are very
different from the summer monsoons.
During winter monsoons, the wind blows from the
land to ocean, while in the summer it is the
This can cause major climate changes throughout
the entire world, depending on the location.
An Avalanche is a movement of snow, ice and
rock down a mountainside. Avalanches happen
very suddenly and can move as fast as a racing
car up to 124mph.
Avalanches can be caused by –
snow melting quickly
snow freezing, melting then freezing again
a loud noise or an earth tremor
A flood is caused by an overflow of water which
covers the land that is usually dry.
Floods are caused by heavy rain or by snow
melting and the rivers burst their banks and
Costal floods are caused by high tides, a rise in
sea level, storm waves or tsunami (earthquakes
under the sea).
Floods make an enormous impact on the
environment and society.
Floods destroy drainage systems in cities,
causing raw sewage to spill out into bodies of
This can lead to catastrophic effects on the
Floods cause significant amounts of erosion to
coasts, leading to more frequent flooding if not
Floods make an enormous impact on the
environment and society. Floods destroy
drainage systems in cities, causing raw sewage
to spill out into bodies of water. Also, in cases
of severe floods, buildings can be significantly
damaged and even destroyed. This can lead to
catastrophic effects on the environment as
many toxic materials such as paint, pesticide
and gasoline can be released into the rivers,
lakes, bays, and ocean, killing maritime life.
Floods may also cause millions of dollars worth
of damage to a city, both evicting people from
their homes and ruining businesses. Floods
cause significant amounts of erosion to coasts,
leading to more frequent flooding if not
A drought is the lack of rain for a long time.
In 1968 a drought began in Africa. Children born
during this year were five years old before rain
•Drought can weaken an
ecosystem by stressing plant
and animal resources.
•Flora and fauna not able to
find adequate resources are
more vulnerable to predation
•Dry conditions can increase
not just the number but the
severity of fires
•Drought, of itself, is a
devastating event, leading to
crop loss and possible topsoil
Drought, of itself, is a devastating event, leading
to crop loss and possible topsoil loss. It also
carries another equally serious impact. Dry,
compacted soils provide little opportunity for
rainwater to penetrate during storms. Droughtaffected areas then become vulnerable to
floods. Stream banks are easily eroded without
the soil-anchoring vegetation lost during a
drought. A buildup of forest litter also increases
the risk of wildfires.
The effects of drought can be felt in every
aspect of society, the economy and the
environment. While the immediate effects are
devastating, long term effects can persist,
compounding damage and loss.
Fires can burn out of control in areas of forest or
bush land. Fires are caused by lightning, sparks
of electricity or careless people. Wind may blow a
bushfire to areas where people live.
Fire effects are the
physical, chemical, and
biological impacts of
fire on ecosystem
resources and the
effects of fire include
its role in changing
soil properties, and
Biotic effects include
altering vegetation and
related impacts on
A tsunami is a series of
tremendous waves generated
by a massive underwater
Tsunamis can move at speeds
as high as 500 miles per hour.
capable of causing a
One tsunami can
destroy an entire
coastal village and
remove all the sand
from a beach and
sand that took
hundreds of years to
Electrical storms are
composed of lightning and
accompanied by heavy
Each storm forms in large
one to five miles in
diameter with a height of
Electrical storms are an amazing phenomenon.
it is not considered a very dangerous natural
It is a very isolated event as each lightning
strike only affects a minimal area and rarely
kills or injures humans and animals.
Lightning does contain a significant amount of
power, reaching temperatures hotter than the
surface of the sun, and creating shockwaves
that we hear as thunder
A forest fire caused by an electrical storm
A tree split in half by lightning
Lightning over a city at night
Lightning striking a tall tree
Natural Disaster Effects | eHow.com
Read more: How do Droughts Effect the Ecosystem? |