volcanoes

• Volcano locations


  • Volcanoes form when magma, which is molten rock from beneath the Earth's crust, reaches the surface
  • Volcanoes usually form along plate margins, where crustal plates are either moving towards or away from one another
• Constructive margin


  Where two plates move away from one another, causing magma to rise up and fill the gaps
• Destructive margin


  Where two plates move towards one another, causing the oceanic crust to sink beneath continental crust at a subduction zone, creating magma which rises to form a volcano
• Volcanoes affect different places in different ways, causing more damage in poorer countries with fewer resources to predict and prepare for them
• Structure and common features of volcanoes


  • Magma chamber - where molten rock is stored beneath the ground
  • Main vent - channel through which magma travels to reach the Earth's surface
  • Secondary vent - where magma may escape through the side of the volcano
  • Crater - found at the top of the volcano where magma erupts from
• Positive effects of volcano eruptions


  • Geothermal energy generation
  • Ash acts as a good fertiliser
  • Volcanoes attract tourists
• Negative effects of volcano eruptions


  • Volcanoes are dangerous, can kill people and damage property
  • Economic activity can suffer after an eruption
  • Habitats and landscapes are damaged by lava flows
• Composite volcanoes


  • Found on destructive plate margins
  • Acidic, viscous lava
  • Steep sides
  • Alternate layers of ash and lava
  • Violent eruptions
  • Longer periods between eruptions
• Shield volcanoes


  • Found on constructive plate margins
  • Basic, runny lava
  • Gentle sides
  • No layers, just lava
  • Less violent eruptions
  • Shorter periods between eruptions
• Volcanic eruptions are unpredictable
• Techniques for monitoring volcanoes

  • Seismometers to measure earthquakes
  • Tiltmeters and GPS satellites to monitor landscape changes
  • Robots to measure gas release
  • Measuring temperature
  • Analysing past eruption patterns
• Benefits of living by a volcano


  • Volcanic rock and ash provide fertile land
  • Volcanoes attract tourists, boosting the local economy
  • Geothermal energy can be harnessed for cheaper electricity
  • Minerals in lava can be mined