The Restless Earth

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  • Created by: Han2812
  • Created on: 03-06-13 09:44

Types of Plate Boundaries

Conservative Plate Margins:

  • Plates slide past each other  (going past each other)
  • Can cause really large earthquakes if plates get stuck
  • Eg. San Andreas Fault (Californa), boundary between North American and Pacific Plate

Destructive Plate Margins:

  • Plate push against each other
  • Cause earthquakes, COMPOSITE volcanoes, fold mountains and ocean trenches
  • Eg. The Andes, (South America), Nazca and South American Plate

Constructive Plate Margins:

  • Plates pulling apart from each other
  • Can cause earthquakes, SHIELD volcanoes and volcanic islands
  • Eg. The Mid-Atlantic Ridge (goes through Iceland), boundry of N.American and Eurasion plate
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Formation of Types of Volcanoes

Sheild Volcanoes:

  • Plates move apart, magma rise upwards from the mantle to fill the gap
  • This adds new rock to the spreading plates
  • Some maybe be forced to go to the surface through the vent
  • If an underwater volcano grows high enough, can form volcanic islands eg Iceland

Composite Volcanoes:

  • Plate collide, denser oceanc plate is pushed down into the mantle, get melts in the subduction zone and forms a pool of lava
  • The heat and pressure may force the magma along a crack where it errupts at the surface and forms a volcano
  • Eg. Krakatoa in Indonesia
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What are they?

  • Huge volcanoes, that errupt with at least 1000 km3 of erruptable material
  • It forms a depression, called a caldera
  • They errupt infrequently,1000s of years apart, have very large and violent eruptions if they do
  • The effects are felt globally, with the ash affecting the land around and the atmosphere above, having significant and long term effects across the world


  • Magma cannot escape to the surface and collects under the lower crust
  • An 'uplifted bulge' begins to form under the lower crust as the magma chamber enlarge
  • Cracks appear on the surface. Gas and ash erupt from the magma chamber through these cracks
  • The magma chamber collapses and a depression is formed. This is called a caldera


  • Yellowstone, Yellowstone National Park, USA - its depression is 55km by 80k wide
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Fold Mountains


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Land Use of Fold Mountains - European Alps


  • Dairy - moving cattle to higher Alps in summer (grass) and feeding on hay in the winter
  • Today cable cars bring milk down to the valley floor
  • Also buys foodstuff for cattle to stay on valley floor all year round


  • On North facing slopes - cuting down of coniferous trees
  • Use wood for buildings and fuel, to make pulp and paper


  • All year round (skiing, snowboarding, climbing, walking etc)
  • Hotels, restuarants, ski lifts etc build on flat land of the high alps - helps economy
  • Promblems: warming up means less snow, more skiers - worn slopes/soil erosion

HEP (Hydroelectric Power)

  • Steep slopes, high rainfall, snow melt = fast flowing rivers, ideal for HEP
  • Narrow valleys can be dammed, lakes can store the water
  • Cheep HEP - used for industry eg, saw mills, aluminium smelting. Sold to other countries
  • No minerals but high population is wealthy so technology can be used to develop the area, eg, electric railways, cable cars, build tunnels etc, allowing more tourism
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Earthquake Case Studies - Japan

MEDC - Japan, March 11th 2011

Epicentre: 30 miles of the East coast of Japans largest island

Time: 2.46 pm

Magnitude: Richter Scale - 9.1    Mercalli Scale - IX

Plates involved: Pacific + Eurasion plates, DESTRUCTIVE plate boundary

Primary Effects: 15,854 deaths, some buildings collapsed but mostly stayed standing

Secondary Effects: Tsunami - waves up to 40m hight, flowed 6 miles inland, Fukashima nuclear power melt down, over 1000 aftershocks

Immediate Responses: Warning + evacuation of coastal areas due to good warning systems, many countries gave emergency aid

Long Term Responses: Rebuilding of destroyed towns, costing $122 billion, building of larger tsunami walls

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Earthquake Case Studies - Haiti

LEDC - Haiti, 24th January 2010

Epicentre: 16 miles west of the capital Port-au-Prince

Time: 4.53 pm

Magnitude: Richter Scale - 7  Mercalli Scale - X (10)

Plates Involved: Caribbean + North American Plate, a CONSERVATIVE plate boundary

Primary Effects: 316,000 dead, 300,000 injured, 1 million homeless people. Major buildings in Port-au-Prince were destroyed - Presidential palace, parliment, cathedral, UN building, jail

Secondary Effects: 1 million people living in shelters, shortages of food. Disease - cholera, especially in refugee camps. Hospitals overwhelmed. Economy collapsed

Immediate Responses: Emergancy Aid given from MEDCs. USA took control of rescue effor as Haiti govement had been killed

Long Term Responses: $5.3 billion has been pled by MEDCs (USA, UK) to rebuild the capital

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Tsunami Case Study - Japan Tukuku 2011


  • Earthquake magnitude (9.1) - slippage on Paific ocean floor, causing it to fall by 10m
  • Water is displaced, wave moved west towards Japan and across the pacific


  • Breached sea walls, flooded 10km in land
  • killed estimate 20,000
  • knocked out the Fukushima nuclear power plant
  • production slowed (honda - swindon)


  • immediate alerts sent via tv, phones, radios etc, costal areas were warned,
  • safe places were identified and drills were paracticed every 3 months, so people knew what they should do
  • buildings constructed to withstand earthquakes
  • sea walls were build around 40% of japan coast to defend against tsunamis


  • Earthquake waas bigger than predicted, tsunami was taller than predicted, protective measures werent that good so massive scale of damage + relativly high death toll
  • 2 year afterwards, nuclear power plant is still too dangerous to enter
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Other Key Terms

Lava: Molten rock on the surface

Acid Lava: High viscosity, moves slowly, thick, from composite volcanoes

Basic Lava: Runny, love viscosity, moves fast, from shield volcanoes

Magma: Molten rock, found in the crust/mantle/volcano

Crust: Hard rock, cracked into different tectonic plates

Oceanic Crust: Made out of basalt, more dense, averages 5 km in thickness

Continental Crust: Made out of granite, less dense, averages 30 km in thickness

Mantle: Closer to the surface, molten rock

Core: In the centre of the earth, Temp 5500 degrees, solid rock

Crater: Opening of a volcano, where the lava comes out

Vent: Vertical cut/gap in a volcano that magma rises through to the surface

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