Geography Raise a Grade Session Hazards

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Geography Raise a Grade Session - Hazards
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Natural Hazards
A Natural Hazard is a natural event which is
perceived by people as a threat to life and
property. It may be generated from within the
Earth (earthquakes, volcanoes), occur upon the
surface (landslides, avalanches, floods), or
happen within the atmosphere (high winds,
drought, snow, fog).
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Plate Tectonics
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Earthquake Prediction

• Ground changes.
• Ground temperature.
• Environmental Changes.
• Past History.

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Benefits of Tectonic Activity.

• Geothermal Energy.
• Fertile Soils.
• Tourism.
• Building Materials.

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Where is Mount Pinatubo?
Population density Luzon
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What caused the volcanic eruption?
Filipino plate
Eurasian plate
Eurasian plate
Filipino Plate being subducted

• The Philippines lie on a destructive plate
  boundary, where the Filipino Plate, composed of
  oceanic crust moves in a north-westerly direction
  towards the Eurasian Plate. When they meet, the
  oceanic Filipino Plate is subducted under the
  Eurasian Plate. The oceanic plate is turned into
  magma, rises and erupts on the surface to form
  composite / strato volcanoes like Pinatubo.

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What happened on June 15th 1991?
5 billion cubic kms of ash pushed up to
21miles high. Travelled around the world
reduced global temps by 0.7 ºC
Pyroclastic flows
Lahars have destroyed more than 100,000 homes
especially those near river valleys
Lahars travelled up to 50kms at 50 km/h burying
villages like Lourdes
Lahars travelled down the Bambam river burying
people houses and crops
Ash lead to 2,000,000 roof collapses and
breathing difficulties
10 cm ash deposited over 2000 km2. over 5000
houses destroyed including these at Clark Air
Base.
Ash in Manila blocks roads and covered 40,000 ha
of farmland. Harvests effected 91 92
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Kobe Earthquake

• January 1995 at 5.46am
• 7.2 on the Richter scale.
• Lasted for 20 seconds.
• 616 aftershocks in the same day.

• Short Term Effects
• 5477 deaths.
• 172,000 homes collapsed.
• Fires.
• Evacuation.
• Transport network devastated.
• Water, gas and electric supplies
  devastated.Long Term Effects
• Businesses forced to close.
• Extra jobs created in construction industry.
• 10 billion yen cost in damages.
• Kobes population fell by 33,000 due to people
  moving away.

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Tropical Storms.
Lower pressure in the centre.
Faster winds in the centre.
Rapid uplift of air
Water is needed to give the storm energy.
Seas must be over 27ºc
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What causes Tropical Storms? Put these statements
into the correct order
Rising air creates low pressure. Air rushes in to
fill gap left by rising air.
The storm continues to feed itself. Latent heat
makes air rise even more.
Air on surface of ocean is heated (it also
contains lots of moisture)
Rotation of the earth means winds do not blow
straight. Winds circle towards the centre.
The tropical storm losses its energy and dies
out.
When the system crosses the land it losses its
source of heat and moisture.
Hot, humid air rises, cools and condenses. Clouds
form.
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What causes Tropical Storms?
1. Air on surface of ocean is heated (it also
contains lots of moisture)
2. Hot, humid air rises, cools and condenses.
Clouds form.
3. Rising air creates low pressure. Air rushes
in to fill gap left by rising air.
4. Rotation of the earth means winds do not blow
straight. Winds circle towards the centre.
Could be interchangeable
5. The storm continues to feed itself. Latent
heat makes air rise even more.
6. When the system crosses the land it losses
its source of heat and moisture.
7. The tropical storm losses its energy and dies
out.
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River Floods
Causes Heavy rainfall Saturated
ground Snowmelt Deposition of silt Dam
failure Deforestation Urbanisation
Prevention Levees Improved services Re-afforestat
ion Flood Action Plan Aid
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River Floods Boscastle, 2004.

• 75 cars and 6 buildings washed into the sea loss
  of water and electric
• no major injuries or loss of life were reported
  loss of industry
• 90 of Boscastles economy is tourism and about
  2/3 of this income usually occurred during the
  school holidays

• Responses
• 4.5m scheme to improve flood defences.
• The scheme stretches along the valley,
  incorporating drainage, sewerage systems and land
  re-grading.

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River Floods Bangladesh 1998.

• 30 million homeless
• gt1000 dead
• loss of water and electric
• communications destroyed
• loss of industry

• Difficulties in Bangladesh
• 92 of catchment
• outside the country.
• Cost!
• Corruption (officials helping
• themselves to government money).
• Priorities (trade!)
• Size of problem.
• Increasing population.

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Exam Practice

• What are the most important words in this
  question?

2. What would you need to do to get an A for
this question?
MARK SCHEME L1 (1 4 marks or C/D grade) Names
and locates the hazard and gives something simple
in (i) or (ii) or develops one of them. L2 (5
7 marks or B grade) Something written in each
section and develops section (i) or (ii), with
some detail. L3 (8 9 marks or A grade)
Develops both sections with specific detail.