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Hazards

Hazards. natural environment presents hazards and offers opportunities for human activities. Reference should be made to the hazards posed by volcanic eruptions, earthquakes, tropical storms, flooding and drought. Volcanic hazards: case study; Etna. Why live there?

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Hazards

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  1. Hazards

  2. natural environment presents hazards and offers opportunities for human activities. • Reference should be made to the hazards posed by volcanic eruptions, earthquakes, tropical storms, flooding and drought.

  3. Volcanic hazards: case study; Etna • Why live there? • The fertile volcanic soils; agriculture with vineyards and orchards across the lower slopes of the mountain and the Plain of Catania to the south. • They can generate electricity from the volcano using geothermal power; • The volcano attracts tourists and residents of nearby Messina and Catania earn money from renting accommodation to tourists; • The Italian government have invested money in prediction by building walls, also it is closely monitored and they are willing to take the risk • The height of the volcano gives snow, - skiing at RifugioSapienza • (Iceland; hot pools)

  4. Issues Volcanic hazards at Etna are: • (1) lava flows, RifugioSapienza on the south side of Mount Etna, Sicily, in December 2002. • (2) tephra falls (and volcanic ash plumes endangering air traffic), closure of Catania airport 2-3 times a year • (3) earthquakes related to eruptive activity and magma movement, • (4) volcanic sector collapse, • (5) tsunami, 4000 BC! • (6) pyroclastic flows.

  5. Earthquake: Sichuan Earthquake: 12th of May 2008: 2:30 PM that's 10 km. magnitude 7.9. • Why live there? • They have lived there all their lives/sentimental attachment; • Close to family/friends; • There are good services/schools/hospitals; • Work in area/fertile farmlands; so they can make a good living • Cannot afford to move; • Pressure of living space; as much of the other land is • Mountainous; • Confidence in safety; • Willing to take the risk; as earthquake has not occurred for many years, • building regs. education.

  6. Tropical storms:

  7. Why occur? • Sea surface temperatures over 27°C; this gives heat and moisture to the system; • A position 5°north or south of the equator to allow the coriolis force to start twisting the rising air; ; • Upper atmospheric conditions which allow the removal of the rising air, like a vacuum cleaner.

  8. Hazard vulnerability: physical factors depends on devel of country • the wind speed,. As the hurricane moves inland it decreases in intensity so damage is less • . Hurricanes usually move at between 6 and 50 kph. Slower moving storms will obviously cause more damage than faster ones. • These storms can bring torrential rain over 2000 mm in two days is not uncommon. This brings floods and the threat of landslide. • Finally storm surges on the coast can penetrate far inland.

  9. Management • Prediction: The National Hurricane Centre monitors the situation. But it is important that if possible a 12-18 hours warning is given. It is estimated that the cost of evacuating the USA coastline is $1 million per km. LEDCs now tend to have the ability to warn people. • Prevention: Not really possible, but there are theories that if rain occurred over the sea the impact would be possible. • Protection: That means being prepared; through education and information, (e.g. Project Safeside) as well as hard defences such as sea walls.. In LEDCs shelters are needed. MEDCS also have the possibility of insurance to limit the subsequent problems.

  10. Katrina: 23 August 2005 Primary effects • category 5 average wind speeds 175 mph gusts up to 215 mph • Storm surge, 10 m high waves • Secondary effects • 2000 dead • $80 bn cost

  11. Response • Short • Evac of New Orleans, 15,000 to Superdome • Long • Rebuild of levees and new plans

  12. Flooding: Boscastle

  13. Drought as a hazard • A drought is an extended period of months or years when a region notes a deficiency in its water supply. • Drought in Australia is defined as rainfall over a three month period being in the lowest 10% of rainfall of what has been recorded for that region in the past.

  14. Since 1992 this area of has experienced the worst drought in over 100 years and this was intensified in 2006 which recorded the lowest rainfall since 1900. The situation worsened as temperatures reached their highest on record. This has been called the Big Dry.

  15. The Murray Darling rivers provide over 70% of irrigation water to the farming areas which produces 40% of Australia's food. • many small settlements on the margins of cultivation are falling in population as a future in farming is seen to be redundant • many livestock areas are suffering as reservoirs have gone dry • abattoirs and wool plants have cut consumption by 30% • tap water is now unfit for human consumption so bottled water must be bought • bushfires have caused a major problem around Sydney

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