Plate Tectonics and Volcanoes

• Lithosphere


  Solid part of the Earth
• Layers of the Earth

  • Crust
  • Mantle
  • Core
• Earth's crust


  • Composed of several broken plates that move continuously
  • Movements caused by properties and processes in the Earth's interior
• Convection cells in the Earth's interior

  1. Warmer material from lower mantle near core rises

  2. As it rises, it slowly cools down and sinks again

  3. Replaced by rising warmer material

  4. Forming a never-ending cycle
• Continental Drift Theory


  • Earth was once composed of only one supercontinent called Pangaea
  • Pangaea split into two sub-continents, Laurasia and Gondwanaland
  • Laurasia split into smaller continents forming the continents in the northern hemisphere
• Seafloor Spreading Theory


  Seafloor is continuously spreading and the extra crust gets recycled into the mantle
• Plate Tectonics Theory

  • Crust is composed of different plates which move either towards, away or past each other
  • Modern version of the Continental Drift Theory of Alfred Wegener
• Types of volcanoes (by structure)

  • Cinder Cone Volcano
  • Shield Volcano
  • Composite Volcano or Stratovolcano
• Cinder Cone Volcano


  • Steep slope
  • Emits ash during eruption
• Shield Volcano


  • Wide base
  • Emits lava
  • Looks like a shield
• Composite Volcano


  • Emits both ash and lava
• Types of volcanoes (by activity)

  • Active Volcano
  • Dormant Volcano
  • Extinct Volcano
• Active Volcano


  Currently erupting or expected to erupt in the near future
• Dormant Volcano


  Not currently erupting but have erupted within recordable history and are expected to erupt again in the future
• Extinct Volcano


  Considered as dead and are not expected to erupt in the future