volcanoes and earthquakes

• where do volcanoes occur?

  destructive & constructive plate margins
• how does a volcano form at a destructive margin?

  • denser oceanic plate moves down into mantle
  • melts
  • pool of magma forms
  • when magma reaches the surfaces erupts, forming a volcano
• how does a volcano form at a constructive margin?

  • magma rises into the gap
  • forming a volcano
• what are hotspots?


  parts of the mantle that are really hot - volcanoes can form here
• what plate margins do earthquakes occur at?


  destructive, constructive, conservative
• how does an earthquake form at destructive margins?

  tension builds when one plate gets stuck
• what is the moment magnitude scale?

  measure the amount of energy released by an earthquake
• how can buildings and structures be designed to reduce the effects of earthquakes?

  • reinforced concrete - special foundations that absorb earthquakes energy
  • wrapping pillars in steel frame - less likely to collapse
  • automatic shut off switches - turn of gas and electric supplies - prevent fires
• How can the risks from earthquakes

  be reduced?

  • Monitoring and prediction - Radon gas

  detection, seismometers to measure

  foreshocks.

  • Protection - constructing buildings to

  withstand earthquakes

  • Planning - preparing emergency aid

  supplies, earthquake drills and training

  people to respond e.g. how to turn off gas

  and electric supplies
• How can the risks from volcanoes be reduced

  • Monitoring - tilt meters / GPS to detect

  changes in the shape, gas monitoring

  • Prediction - monitoring changes in the

  shape of a volcano enables scientists to

  make predictions

  • Protection - evacuation of people

  • Planning - evacuation plans, education

  and creating exclusion zones.