Environmental Hazards Revision

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Environmental Hazards Revision

• Tectonic Plates
• Structure of the earth
• Location of Volcanoes, earthquakes and tropical
  storms
• How each forms/occurs
• Effects of all natural disasters on people and
  landscape
• Methods used to measure/record natural disasters

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THE EARTHS LAYERS
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Earth Layers

• The Earth is divided into four main layers.
• Inner Core
• Outer Core
• Mantle
• Crust

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The Crust

• The Earths crust is like the skin of an apple.
  It is very thin compared to the other three
  layers.
• The crust makes up 1 of the Earth.
• The crust of the Earth is broken into many pieces
  called plates.

CRUST
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The Mantle

• The mantle is the layer below the crust.
• The mantle is the largest layer of the Earth.
• The mantle is divided into two regions the upper
  and lower sections.

MANTLE
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Outer Core

• The core of the Earth is like a ball of very
  hot metals.
• The outer core is liquid.
• The outer core is made up of iron and is very
  dense.

Outer Core
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Inner Core

• The inner core of the Earth has temperatures
  and pressures so great that the metals are
  squeezed together and are not able to move.
• The inner core is a solid.

Inner Core
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Review

• 1) What are the four layers of the Earth?
• 2) The Earths crust is very ______?
• 3) The mantle is the largest layer of the Earth?
  True or False
• 4) Is the Outer Core a liquid or a solid?

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What are Convection currents?

• Large thermal currents within the mantle which
  rise towards the surface.
• When they reach the upper mantle they are blocked
  by the solid crust and so have to turn sideways.
• As they do so they cause a drag on the crust and
  so cause it to move very slightly.
• This has caused the crust to break into large
  sections called plates.

http//education.sdsc.edu/optiputer/flash/convecti
on.htm
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What type of plate boundary?
Parting Plate Boundary (constructive)
Colliding Plate Boundary (destructive)
Sliding plate boundary
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Tropical Storms
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By the end of this lesson you should be able to

• Detail where and when tropical storms occur
• Explain the formation of a tropical storm
• Understand the impact of a tropical storm

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Where and when are tropical storms found?

• Tropical storms require warm seas (gt27 degrees
  celsius) which tends to be only found within 30
  degrees of the equator.
• Subsequently, only tend to occur in late summer,
  early autumn (sea temperatures at their highest).

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How does a tropical storm form?

• They form at areas of intense low pressure
  (rising humid air) which causes the air to spiral
  round the eye (centre) at great speeds.

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How are tropical storms recorded?

• Hundreds of weather stations on land and at sea
  record the weather as the hurricane approaches
  and passes over, giving information on its
  wind-speed, wind direction, temperature and
  pressure.

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Radiosonde Balloons are sent into the hurricane
carrying weather instruments and they send back
information on temperature, pressure and
humidity.
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Radar is used to find out where the rain is
falling and its intensity.
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Satellites take photographs of the hurricane so
that its speed and direction can be tracked.
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Specially-designed aircraft fly into hurricanes
and record wind-speed, wind direction and
temperature.
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Computers in the National Hurricane Centre in
Miami, USA process all this data and, based on
how previous hurricanes have behaved (stored in
their memory), they predict the hurricane's
speed, strength and direction over the next few
days.
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What is the impact of a Tropical storm?
Hurricane Mitch
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• Hurricane Mitch formed in the western
  Caribbean Sea on October 22, 1998 and was one of
  the deadliest and most powerful hurricanes on
  record in the Atlantic basin, with maximum
  sustained winds of 180 mph (290 km/h).
• Deaths due to catastrophic flooding made it
  the second deadliest Atlantic hurricane in
  history nearly 11,000 people were killed with
  over 8,000 left missing by the end of 1998. The
  flooding caused extreme damage, estimated at over
  5 billion.