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The earth's atmosphere
is divided into layers on
the basis of changing
temperatures.
The density of the
atmosphere decreases
exponentially as you go
away from the earth's
surface.
99% of atmospheric
gases are in the
troposphere and
stratosphere.
Two factors add complexity to these patterns:
• The coriolis effect produced by the earth's rotation on
its axis
• The earth's topography
The earth's orbit, rotation,
and tilt result in seasons
The earth is tilted
23½° on its axis
relative to its plane
of rotation around
the sun
At equinoxes, the
sun shines directly
on the equator
At solstices, the sun
shines directly on the
northern or southern
hemisphere
Natural hazards are generally rare,
but normal, natural events.
Natural hazards only become disasters
if people are present.
Earthquakes
Earthquakes are shock waves that result when
large masses of rock in the earth's crust move
relative to each other
Volcanoes
Volcanoes are found at places in the earth's
crust where hot, molten rock (magma) wells
up to the surface; found at tectonic plate
boundaries and hot spots
Land Instability
Occurs in many places; includes: landslides,
rockfalls, slumps
Barrier Island coast
Impacts of a jetty on beach
sand deposition and erosion
Tropical cyclones, hurricanes and typhoons are intense
storms that develop over warm tropical areas.
Tornadoes are a rapidly rotating vortice of air that forms
a funnel. When they touch the ground, they can be one
of the most deadly natural hazards.
Floods can be nothing more than a normal but not
frequent natural occurrence but seem disastrous from a
human perspective. Cumulatively, floods are among the
most destructive of natural hazards.
Wildfire
Coastal storm surges
Drought (1988 drought – est. cost of 39 Billion $)
Hail
Estimated deaths and damages caused by
hurricanes since 1900
10000
8000
Deaths
6000
4000
2000
0
Damage
in
Billions
of
Dollars
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
35
30
25
20
15
10
5
0
Estimated deaths from natural hazards
during 1965 to 1995
(tropical storm)
(earthquake)
(flood)
(slides)
(volcano)
Example slides of various natural disasters such as:
Earthquakes,
Tornadoes,
Volcanoes and
Wildfires
are not included on the website.