natural disasters ppt by muzzammil ghayas
DESCRIPTION
Presentation on natural disasters by the students of Iqra University ( Gulshan Campus)TRANSCRIPT
Natural DisastersGroup Members:-1. Tahira Jabbar Shaikh (4377)2. Shahid Hussain (4422)3. Sana Laiq Ali (4384)4. Kamran Mehmood (4424)5. Muhammad Muzammil Ghayas (4338)
Course Instructor:-Miss Mehvish Saleem
Disaster:-
An occurrence causing widespread
destruction and distress.
A catastrophe.
A grave misfortune.
Definitions
A natural disaster is an event caused by
natural forces.
It often has a significant effect on human
populations.
Typically the human populations either are
displaced (left homeless) or killed.
Natural Disasters
Have economic and emotional effect on
people.
Directly affect life and property.
Contd…
Natural disasters occurs in all three broadareas:
Land Air Water
Occurrence & Affects of Natural Disasters
There are 4 kinds of natural disasters whichoccurs on land:
Earthquakes Volcanic Eruptions Lahars Avalanches
Disasters on Land
Earthquake is a sudden shock of earth’s crust.
The underground point of origin is called the
focus.
The point directly above the focus is called
the epicenter.
They are measured with a seismometer.
The scale is called the Richter Scale.
Earthquakes
An earthquake that occurs after the main
shock.
It occurs in the same area or region of the
main shock.
Its magnitude is relatively smaller than the
main shock.
The Aftershocks
If the magnitude of an after shock is greater
than the main shock:
After shock is designated as the main shock.
The main shock is redesignated as the fore
shock.
Designation of Main Shock & The After Shock
Earthquake itself does not kill any one.
Usually the secondary events kill the
people.
Secondary events include:
Tsunami
Building Collapse
Fires
Volcanoes
Earthquakes does not Kill People
A volcano is an opening in earth’s crust.
It allows hot magma, ash and gasses to
come out from below the surface.
They are generally found where tectonic
plates are diverging or converging.
Volcanic Eruptions
Volcanoes can be destructive.
Can be harmful for the life and property.
Icelandic volcanic eruption continued for
nearly 3 months.
Caused thousands of
flights to be cancelled.
Contd…
A type of mudslide/landslide composed of
pyroclastic material & water.
It is liquid while moving and becomes solid when
the activity is stopped.
Can flow 100 km/hour.
Can cover a distance of more than 300 km.
Can be deadly due to their energy & speed.
Killed 23000 people in Armero , Columbia in 1985.
Lahars
An avalanche is a rapid flow of snow down a
slope.
Primarily composed of flowing snow.
It occurs in mountainous regions.
It can mix air and water with descending snow.
Most destructive natural disaster in the
mountainous regions.
Avalanches
Wellington Avalanche (1910)
Blons Avalanches (1954)
Some Notable Avalanches
There are basically three types of naturaldisasters which occurs in or due to the water:
Floods Tsunami Limnic eruptions
Water Disasters
A flood is an overflow of water.
They occur when the flow of water exceeds
the capacity of river.
Heavy rain is another reason.
Can be destructive for life and property.
Floods
A tsunami is a series of water waves.
It is caused by the displacement of a large
volume of a water body.
Caused by the underwater earthquakes,
volcanic eruptions and
underwater explosions.
Can destroy coastal areas.
Tsunami
Frequent in Japan.
In 2004, Indian Ocean Tsunami caused widespread
destruction.
Hundreds of thousands of people were killed in different
countries.
During 2nd World War, New Zealand army tried to create
an artificial tsunami.
New Zealand army was failed to create the artificial
tsunami.
Contd…
Can not be predicted correctly even if magnitude
and place of quake is known.
Pacific tsunami warning system monitors Pacific
Ocean’s seismic activities.
People can save their lives by going
to the places higher than the land.
Sign boards are placed in US to
show the people where to go.
Countering Tsunami
A rare type of natural disaster.
Occurs in lakes.
Occurs when a gas (carbon dioxide) erupts deep
under the water.
Large cloud of carbon dioxide forms above the lake.
Killed 37 people in Cameron at Lake Monoun in 1984.
Killed 1700-1800 people in Cameron at Lake Nyos.
Limnic Eruptions
Air Disasters
Tornado
A rotating column of air.
In contact with both surface of earth and
the cloud.
Approximate length is 250 feet (80 m).
Usually wind speed is 110 miles/hour.
Can attain wind speed of more than 300
miles/hour.
Tornado
Multiple-Vortex Tornado
Water Spout
Dust Devil
Fire Whirls
Steam Devil
Some Other Types of Tornadoes
Multiple-Vortex Tornado
2 tornadoes moving simultaneously
Waterspout
A tornado over the Water
Dust Devil
A Dust Devil
Fire Whirls
A tornado of fire
Steam Devils
Multiple tornadoes of Smoke
Humans can not control the nature.
Better understanding of natural disasters
and causes can help us in minimizing the
damage.
By proper disaster management thousands
of lives can be saved.
Conclusion
Q & A