Hazardous Earth

• What are tectonic hazards?


  Natural events caused by convection currents in the mantle moving the plates as they rise and cool.
• What is the plate tectonic theory?


  Wegener stated the Earth used to have a super continent called Pangea but the plates have moved apart.
• What are the 4 pieces of evidence for the plate tectonic theory?

  1. Contients seem to fit together
  2. Fossils found on different continents eg. Mesosaurus found in Africa and America but could not swim
  3. Paleomagnetism
  4. Similar coal deposits in UK, USA, Antarctica
• What is a divergent plate boundary?

  2 oceanic plates move apart
• What is a conservation plate boundary?


  2 land plates rub past each other
• What is a convergent plate boundary?

  • Land plate subducts the ocean plate
  • new Ocean plate subducts the older ocean plate
  • Land plate hit land plate and both rises
• What is a hotspot?


  Area of the crust that has a high heat flow away from plate boundaries
• How do hotspots release lave from crust?

  Strong currents raise mantle plumes which push the surface and if able to peirce lava will be released
• Explain the Hawaiian islands:

  • Formed by hotspots
  • Pacific plates move 7 cm a year
  • Population is evacutated and educated
• What is a explosive volcano?


  Viscous lava on a convergent boundary called stratovolcano
• What is a effusive volcano?


  Thin lava on a divergent boundary called a shield volcano
• What is VEI and what does it take into account?

  Volcanic explosive index 0-8

  • Magnititude = amount
  • Intensity = speed
• What is a lava plateau?


  Crack in grownd that lava can seep through
• What are volcanic hazards?

  1. Lava flows
  2. Pyroclastic flows
  3. Tephra
  4. Toxic gas
  5. Lahar
  6. Flooding
  7. Tsunami
• How many people live near volcanos and why?

  600 million people live near

  • uneducated
  • Cheap
  • Managment
  • Family
• Explain Iceland:

  • Geothermal energy (20%)
  • Geothermal heating (89% with 2200Km pipes)
  • Tourism (354000 visitor to lagoon)
• What is an earthquake?


  Release of stress from the crust
• What are P waves?


  fast and pass through everything
• What are S waves?


  slow and pass only through solids
• What are L waves?


  Slowest and pass only through the crust
• What is a shallow focus?


  70Km
• What is a deep focus?


  70km to 700km
• Where do earthquakes happen?

  on fault lines
• Where is the epicentre?


  Above where the waves originate
• What are the 3 ways to measure earthquakes?

  • Richter scale
  • Moment magnitude scale
  • Modified Mercalli scale
• What are 3 landforms created by earthquakes?

  1. Rift valleys eg. East African
  2. Fold mountains eg. Himalaya
  3. Mid oceanic ridge eg. Atlantic
• What are 4 hazards created by earthquakes?

  1. Landslides / Avalanche eg. Nepal, blocked transport and dams
  2. Tsunami eg. Sumatra, 1000 tonnes of water
  3. Shaking / Displacement
  4. Liquifaction eg. Kobe, port destroyed hurt economy and trade
• What are the 5 stafes of the disaster response curve?

  1. Modify event / vulnerablity / loss
  2. Tectonic event
  3. Search and rescue
  4. Relief
  5. Recover
• Modify the event AC examples...

  Italy built lava channles and barriers
• Modify the vulnerablity AC example...

  Italy monitors and early alerted population
• Modify the vulnerablity EDC example...

  Idonesia monitor the volcano as they have a prepared government. Also have sensors to detect lahars.
• Modify the vulnerablity LIDC example...

  Haiti are not prepared as are not earthquake resistant nor managed and do not monitor the hazards.
• Modify the loss AC example...

  Italy has the resources and evacuation plan. This is needed as 600000 people live in the red zone.
• Modify the loss EDC example...

  Indonesia has strong bonds with other countries to help them. Individually they have trained services and temporary shelters ready.
• Modify the loss LIDC example...

  Haiti is helped by NGO that provided $5.3 billion. However, only gave 1% of the money so Haiti struggled a lot more.