Raise A Grade Session Hazards


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Raise A Grade Session Hazards

  1. 1. Geography Raise a Grade Session - Hazards
  2. 2. 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).
  3. 3. Plate Tectonics San Francisco Large earthquakes. Conservative Himilayas Fold mountains, earthquakes. Collision Japan Subduction zone, ocean trenches, island arcs, volcanoes and earthquakes. Destructive Mid-Atlantic Ridge Continuous small volcanoes. Earthquakes. Constructive Location Effects/ Landforms Diagram
  4. 4. Earthquake Prediction <ul><li>Ground changes. </li></ul><ul><li>Ground temperature. </li></ul><ul><li>Environmental Changes. </li></ul><ul><li>Past History. </li></ul>
  5. 5. Benefits of Tectonic Activity. <ul><li>Geothermal Energy. </li></ul><ul><li>Fertile Soils. </li></ul><ul><li>Tourism. </li></ul><ul><li>Building Materials. </li></ul>
  6. 6. Mount St Helens <ul><li>May 1980. </li></ul><ul><li>Destructive Boundary </li></ul><ul><li>Earthquakes and large volcano </li></ul><ul><li>Monitored for over 2 months before the eruption because the volcano was bulging. </li></ul>Effects: Landscape – vegetation destroyed, landslides, land covered in volcanic deposits. Farming – Short term loss of crops and livestock, but eventual increase in fertility of soil. Forestry – forests flattened, logging industry destroyed. Communications – rivers blocked, roads and bridges washed away by flooding. Fishing – Raised water temperatures led to loss of fish. People – Evacuation, many inhaled toxic gases. Tourism – Tourists attracted – tourist centre set up in 1993, attracting >1 million visitors a year.
  7. 7. Kobe Earthquake <ul><li>January 1995 at 5.46am </li></ul><ul><li>7.2 on the Richter scale. </li></ul><ul><li>Lasted for 20 seconds. </li></ul><ul><li>616 aftershocks in the same day. </li></ul><ul><li>Short Term Effects </li></ul><ul><li>5477 deaths. </li></ul><ul><li>172,000 homes collapsed. </li></ul><ul><li>Fires. </li></ul><ul><li>Evacuation. </li></ul><ul><li>Transport network devastated. </li></ul><ul><li>Water, gas and electric supplies devastated. Long Term Effects </li></ul><ul><li>Businesses forced to close. </li></ul><ul><li>Extra jobs created in construction industry. </li></ul><ul><li>10 billion yen cost in damages. </li></ul><ul><li>Kobes population fell by 33,000 due to people moving away. </li></ul>
  8. 8. Tropical Storms. Seas must be over 27 º c Water is needed to give the storm energy. Rapid uplift of air Faster winds in the centre. Lower pressure in the centre.
  9. 9. Tropical Storms – Bangladesh. <ul><li>April 1991. </li></ul><ul><li>12,000 dead, 28,000 injured. </li></ul><ul><li>Food shortages. </li></ul><ul><li>Loss of income. </li></ul><ul><li>Dirty water. </li></ul><ul><li>Loss of homes. </li></ul><ul><li>Prediction/Prevention. </li></ul><ul><li>Evacuation schemes. </li></ul><ul><li>Coastal defences. </li></ul><ul><li>Emergency services training. </li></ul><ul><li>Reinforced buildings. </li></ul><ul><li>Forecasting. </li></ul><ul><li>Effects: </li></ul><ul><li>Strong winds. </li></ul><ul><li>Torrential rain. </li></ul><ul><li>Storm surges. </li></ul>
  10. 10. River Floods Causes: Heavy rainfall Saturated ground Snowmelt Deposition of silt Dam failure Deforestation Urbanisation Prevention: Levees Improved services Re-afforestation Flood Action Plan Aid
  11. 11. River Floods – Bangladesh 1998. <ul><li>30 million homeless </li></ul><ul><li>>1000 dead </li></ul><ul><li>loss of water and electric </li></ul><ul><li>communications destroyed </li></ul><ul><li>loss of industry </li></ul><ul><li>Difficulties in Bangladesh: </li></ul><ul><li>92% of catchment </li></ul><ul><li>outside the country. </li></ul><ul><li>Cost! </li></ul><ul><li>Corruption (officials helping </li></ul><ul><li>themselves to government money). </li></ul><ul><li>Priorities (trade!) </li></ul><ul><li>Size of problem. </li></ul><ul><li>Increasing population. </li></ul>
  12. 12. Drought <ul><li>Factors affecting: </li></ul><ul><li>temperature </li></ul><ul><li>previous rainfall </li></ul><ul><li>run off </li></ul><ul><li>wealth </li></ul><ul><li>population </li></ul><ul><li>land-use </li></ul><ul><li>Effects: </li></ul><ul><li>Less water </li></ul><ul><li>Fire </li></ul><ul><li>Subsidence </li></ul><ul><li>Reduced Yields </li></ul><ul><li>Less water for industry </li></ul><ul><li>Hosepipe bans </li></ul><ul><li>MEDC e.g.Texas 1998 </li></ul><ul><li>Lack of rain (for 5 months) </li></ul><ul><li>High temperatures (41 ºc) </li></ul><ul><li>High demand for water </li></ul><ul><li>LEDC e.g. the Sahel </li></ul><ul><li>Human activity – clearance </li></ul><ul><li>Starvation and famine </li></ul><ul><li>Loss of cattle </li></ul><ul><li>Lack of rainy season. </li></ul>
  13. 13. Past Paper Question – June 2001 <ul><li>Question B5 </li></ul><ul><li>c) Describe the physical processes that are responsible for drought. (4) </li></ul><ul><li>Human activity can make the effects of hazards worse. Explain how this happens. (4) </li></ul><ul><li>For a natural hazard that you have studied: </li></ul><ul><ul><li>Explain the physical processes responsible for the hazard. </li></ul></ul><ul><ul><li>How might people be protected from the hazard? </li></ul></ul><ul><ul><li>You should refer to any examples you have studied in your answer. (8) </li></ul></ul>