This document discusses different types of natural disasters including floods, earthquakes, tsunamis, volcanic eruptions, wildfires, avalanches, and epidemics. It explains the causes of these disasters such as heavy rainfall causing floods, tectonic plate movement causing earthquakes, volcanic magma releases causing eruptions, and disease transmission causing epidemics. The effects of natural disasters like property damage, loss of life, and economic impacts are also mentioned. Examples of specific historic natural disasters are provided like the 1918 Spanish flu pandemic and avalanches during World War I.
2. What are natural disasters?
• A natural disaster is a major adverse event resulting
from natural processes of the Earth ; examples
include floods ,volcanic
eruptions,earthquakes,tsunamis,and other geologic
processes.
• A natural disaster can cause loss of life or property
damage and typically leaves some economic
damage in its wake, the severity of which depends
on the affected population'sresilience, or ability to
recover.An adverse event will not rise to the level of
a disaster if it occurs in an area without vulnerable
population.In a vulnerable area, however, such
3. Floods
• A flood is an overflow of water that "submerges"
land. The EU Floods Directive defines a flood as
a temporary covering by water of land not
normally covered by water.In the sense of
"flowing water", the word may also be applied to
the inflow of the tides. Flooding may result from
the volume of water within a body of water, such
as a river or lake, which overflows causing the
result that some of the water escapes its usual
boundaries.While the size of a lake or other
body of water will vary with seasonal changes in
precipitation and snow melt, it is not a
significant flood unless the water covers land
4. Causes and Effects
Natural disasters happen all over the world, and
they can be utterly devastating for people’s lives and
the environments in which they live. Although
natural disasters are caused by nature and there is
nothing that we can do to prevent them happening,
there are many different natural causes that lead to
natural disasters, and being aware of these causes
enables us to be better prepared when such
disasters do arrive.One common natural disaster is
flooding, which occurs when a river bursts its banks
and the water spills out onto the floodplain. This is
far more likely to happen when there is a great deal
5. Causes and Effects
There are other risk factors for flooding too: steep-
sided channels cause fast surface run-off, while a
lack of vegetation or woodland to both break the
flow of water and drink the water means that there is
little to slow the floodwater down. Drainage basins
of impermeable rock also cause the water to run
faster over the surface. Earthquakes are another
common natural disaster that can cause many
fatalities. The movements of the plates in the earth’s
crust cause them. These plates do not always move
smoothly and can get stuck, causing a build-up of
pressure. It is when this pressure is released that an
6. Causes and Effects
Tsunamis can also be caused by underwater
volcanic eruptions. Volcanic eruptions are another
natural disaster, and they are caused by magma
escaping from inside the earth. An explosion takes
place, releasing the magma from a confined space,
which is why there are often also huge quantities of
gas and dust released during a volcanic eruption.
The magma travels up the inside of the volcano, and
pours out over the surrounding area as lava. One of
the most common natural disasters, but also one of
the most commonly forgotten, is wildfires. These
take place in many different countries all over the
9. Epidemics
• An epidemicis an outbreak of a contractible disease
that spreads through a human population. A
pandemic is an epidemic whose spread is global.
There have been many epidemics throughout
history, such as theBlack Death. In the last hundred
years, significant pandemics include:
• The 1918 Spanish flupandemic, killing an estimated
50 million people worldwide
• The 1957–58 Asian flupandemic, which killed an
estimated 1 million people
• The 1968–69Hong Kong water flupandemic
• The 2002-3SARSpandemic
• The AIDS pandemic, beginning in 1959
• The H1N1 Influenza(Swine Flu) Pandemic 2009–2010
• Other diseases that spread more slowly, but are still
considered to be global health emergencies by
theWHO, include: XDR TB, a strain of tuberculosis
10. Avalanches
• During World War I, an estimated 40,000 to 80,000
soldiers died as a result of avalanches during the
mountain campaign in the Alpsat the Austrian-Italian
front. Many of the avalanches were caused by
artillery fire.
11. Earthquakes
• An earthquake is the result of a sudden
release of energy in theEarth's crust that
creates seismic waves. At the Earth's
surface, earthquakes manifest themselves
by vibration, shaking and sometimes
displacement of the ground. The vibrations
may vary in magnitude. Earthquakes are
caused mostly by slippage within geological
faults, but also by other events such as
volcanic activity, landslides, mine blasts, and
12. Volcanic Eruptions
• Volcanoes can cause widespread destruction
and consequent disaster in several ways.
The effects include the volcanic eruption
itself that may cause harm following the
explosion of the volcano or the fall of rock.
Second, lava may be produced during the
eruption of a volcano. As it leaves the
volcano, the lava destroys many buildings,
plants and animals it encounters.
Third,volcanic ash generally meaning the