GEO

• Convection currents can move the earth plates in 3 ways

  1. plates move apart - Divergence (divergent movement) E.g South American and African plates
  2. Plates move towards each other - Convergence (convergent movement) E.g Eurasian and pacific plates
  3. Plates slide past each other - Transverse (transform movement) E.g pacific and North American plates
• Fissures: cracks in rocks , the crust through which magma flows

  vents: holes in rocks , the crust through which magma can flow
• A volcano can be caused by tectonic plates moving apart or that have collied with each other
• volcanoes can be

  1. active volcanoes ( erupt almost all the time )
  2. dorment volcanoes ( have erupted in the past but are inactive at this time)
  3. Extinct volcanoes ( have not erupted in a long time but can suddenly)
• igneous rock is rocks formed from magma and lava that became extremely hard and solid
• Parts of the volcano

  A)

  B) ash and dust cloud

  C) creater

  D) lava flow

  E) main vent

  F) secondary vent

  G) Magma chamber

  H) Magma chamber

  I) secondary cone

  J) volcanic bombs

  K) pyroclastic flow

  
• The ring of fire is 40 000 km long. It is where earthquakes and volcanic eruptions occur frequently.
• 90% of the worlds earthquakes occur in the pacific ring of fire
• 81% of the strongest earthquakes occur in the Pacific Ring of Fire