Volcanoes and Supervolcanos

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  • Volcanoes
    • Constructive plate boundaries
      • As the plates move apart, magma rises up to fill the gap that's created. This adds new rock to the Earths surface through a vent.
      • Shield volcano
        • Gentle slopes
        • Wide base
        • Lava is erupted (non-violent)
    • Destructive plate boundaries
      • An oceanic plate and a continental plate move together. The denser oceanic plate sinks below the continental plate and enters the subduction zone, where there is lots of pressure and friction. The oceanic plate melts, creating magma, which rises through cracks in the Earths crust. It explodes up to the surface causing a volcanic eruption. The lava from the eruption cools and forms new crust. After several eruptions the rock builds up forming a volcano.
      • Composite volcano
        • Steep sides
        • Narrower base
        • Erupts lave and ash (violent)
    • Predicting eruptions
      • Bulging around the crater - gas and pressure building up in the vent
      • Increased steam and gas emission - magma heating up
      • Monitoring temperatures - temperature will rise when magma starts to rise
      • Tiltmeter - used to check for movements in the Earth (change in steepness)
      • Measuring small earthquakes in the area - change in activity
    • Super Volcanoes
      • 10,000 times stronger than a normal volcano
      • Magma rises through cracks in the Earths crust forming a magma chamber. The Earths surface is forced bulge. The bulge cracks causing lava to escape through the vents. As the magma chamber empties the rock above collapses causing a caldera to form.
      • Yellowstone National Park lies on top of a super volcano
      • The ash can block out the sun and trigger a mini ice age as less heat energy from the sun can get to the Earth.
      • Power can be measured on the VEI scale . It measures the catastrophic proportions on a scale from 1-8, each leap up the scale represents an increase of 10 times the power.
      • Flat volcano, ejects more than a trillion tons of material when it erupts.


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