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

At equinoxes, the sun shines directly on the equator

The earth is tilted 23½° on its axis relative to its plane of rotation around the sun

The earth's orbit, rotation, and tilt result in seasons

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.

EarthquakesEarthquakes are shock waves that result when large masses of rock in the earth's crust move relative to each other

VolcanoesVolcanoes 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 InstabilityOccurs 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.

WildfireCoastal storm surgesDrought (1988 drought – est. cost of 39 Billion $)Hail

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1900 1910 1920 1930 1940 1950 1960 1970 1980 1990

Deaths

Estimated deaths and damages caused by hurricanes since 1900

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1900 1910 1920 1930 1940 1950 1960 1970 1980 1990

Damage in

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Dollars

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 andWildfires

are not included on the website.