Plate Tectonics

  • Created by: K4t13
  • Created on: 03-06-15 10:34


At a plate boundary:

  • divergent/ constructive margins where the crust is pulled apart and a magma 'plugs' up the gap, forming underwater volcanoes
  • after serval eruptions, the volcanoes can break the ocean surface to form islands

At a plate boundary:

  • Covergent/ destuctive margins where slabs of crust move towards each other
  • the denser oceanis crust subducts
  • as it is forced into the mantle, friction and increasing heat causes the rock to melt
  • as it is hotter, the magma is forced upwards from a magma chamber, exploiting a weakness in the rock and erupts as a volcano

Volcano: Formed by material from the mantle being forced through an opening in the earths crust called a vent.

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Prediction and Prevention (Volcanoes)

Prediction of Volcanic Eruptions

  • GPS- bulging volcano
  • Gas sampling- sulphur!
  • Geothermal monitoring- form space
  • Seismic monitoring- tremors proir to eruption
  • Historical records- can you predict when the next is likely to go
  • EG... Popacatapetl, Mexico 2000- successfully predicted due to detecting small tremours

Preventing Volcanic Eruptions

  • Spraying lava to cool it down
  • Concrete blocks or barriers to divert the flow of lava
  • Setting off explosions to divert lava flow
  • Digging Ditches
  • EG... The Village of Zafferana, Sicily was saved in 1991-1993
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Prediction and Prevention (Earthquakes)

Prediction of Earthquakes

  • Noting animal behaviour
  • Increased electrical dischange prior to a quake
  • Recording/ monitoring foreshocks

Prevention of Earthquakes

  • Providing education to the population about what to do in an emergancy
  • Have an emergancy kit ready
  • Designing 'earthquake' proof building ( eg counter balances; rubberised foundations; fexible steel frames)
  • Planning regulations
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Why do people live in areas of crustal instability

  • Natural resources (tin, silver, copper, gold -> mining=jobs)
  • Geothermal energy (eg Iceland)
  • Fertile soils for farming
  • Low ricks of eruption
  • Tourism
  • Family and friend are there
  • Earthquake proof building
  • Evacuation/Disaster Plans 
  • Low chance
  • Wortht the risk
  • Well-established (eg San Franciso)
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