This document defines and describes several types of natural disasters: Volcanic eruptions occur when pressure forces magma up through a volcano's conduit. Earthquakes are caused by the sudden movement of tectonic plates. Floods happen when heavy rainfall or melting snow causes water levels in rivers and lakes to rise over land. The document also discusses avalanches, droughts, forest fires, hurricanes, lightning strikes, and tsunamis, explaining the causes and impacts of each type of natural disaster.

1. WRITTEN BY:
Alex Mitropoulos
George Soultojohn
Thanos Prokopakis
John Lebetlis
Vaggelis Nanos

2. 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.

3.  Volcanic eruptions
 Earthquake
 Flood
 Avalanche
 Drought
 Forest fire
 Hurricane
 Lightning strike
 Tsunami

4.  An eruption begins when
pressure on a magma
chamber forces magma up
through the conduit and out
the volcano’s vents. When the
magma chamber has been
completely filled, the type of
eruption partly depends on the
amount of gases and silica in
the magma. The amount of
silica determines how sticky
the magma is and water
provides the explosive
potential of steam.

5.  An earthquake is a
shaking of the ground
caused by the sudden
breaking and
movement of large
sections (tectonic
plates) of the earth's
rocky outermost crust.

6.  Flooding is when the water
level in a river, lake or the
sea rises and covers land
that is usually dry. While
some floods occur without
problem, others are
devastating, causing large-
scale destruction and
significant loss of life.
Flooding is experienced all
over the world and in some
countries flooding occurs
regularly.

7.  Technically, an avalanche is
any amount of snow sliding
down a mountainside. It can
be compared to a landslide,
only with snow instead of
earth. Another common term
for avalanche is “snowslide”.
As an avalanche becomes
nearer to the bottom of the
slope, it gains speed and
power, this can cause even
the smallest of snowslides to
be a major disaster.

8.  A drought is
considered a period
of abnormally dry
weather that causes
serious hydrological
imbalance in the
area.

9.  A forest fire is a natural
disaster consisting of a
fire which destroys a
forested area, and can
be a great danger to
people who live in
forests as well as
wildlife. Forest fires are
generally started by
lightning, but also by
human negligence or
arson, and can burn
thousands of square
kilometers.

10.  Hurricanes are large
tropical storms with heavy
winds. By definition, they
contain winds in excess of
74 miles per hour (119 km
per hour) and large areas of
rainfall. In addition, they
have the potential to spawn
dangerous tornadoes. The
strong winds and excessive
rainfall also produce
abnormal rises in sea levels
and flooding.

11.  Lightning is a massive
electrostatic discharge
caused by unbalanced
electric charge in the
atmosphere either
inside clouds, cloud to
cloud or cloud to
ground, accompanied
by the loud sound of
thunder.

12.  A tsunami is a series of
ocean waves with very
long wavelengths
(typically hundreds of
kilometres) caused by
large-scale disturbances
of the ocean, such as:
 Earthquakes
 Landslide
 Volcanic eruptions
 Explosions
 meteorites

13. THE END
(THANK YOU FOR YOUR ATTENTION)