Georgraphy

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  • Created by: sidra
  • Created on: 14-05-13 19:20
The Earth's surface is seperated into tectonic plates. Centre = Core, solid iron and nickel. Around the Core = mantle, semi molton-rock. Outer layer = Crust, thin. Which is divided into lots of slabs called tectonic plates which float on mantle.
There are two types of crust. Continental = thicker and less dense. Oceanic = thinner and more dense. The plates are moving because the rock in the mantle underneath them is moving. The place where plates meet are called boundaries or plate margins
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The three types of plate margins are Destructive Margin = two plates are moving towards each other. when an oceanic plate meets continental plate, the denser oceanic plate is forced down in the mantle and destroyed. This often creates volcanoes
and ocean trences (very deep section of the ocean floor where the oceanic plate goes down) Where two continental plates meet, the plates smash together, but no crust is destroyed.
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Constructive plate margins= where two plates are moving away from each other. Magma rises from the mantle to fill gap and cools, creating new crust.
Conservative Margins = when two plates are moving sideways past each other or are moving in the same direction but at different speeds. Crust is not created or destroyed.
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Fold Mountains are formed when plates collide at destructive margins. When plates collide the sedimentary rock that has been built up between them are folded and forced upward to form mountains. They form when a continental and oceanic plate collide.
You can also get them when 2 continental plates collide. Humans use fold mountains for Farming = to graze animals, HEP= to generate HEP, Mining, Forestry = to grow some types of trees(conifers) Tourism= winter + summer activities like skiing and walk
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Case Study-(Alps) They use fold mountains for Farming= steep upland areas are used to farm goats, which provide milk, cheese and meat. Tourism=100 million tourists, 70% tourists visit in the winterand summer to do activities.
New villages have been built to cater for the quantity of tourists. Mining = salt, iron ore, gold, silver and copper were mined in alps. Forestry= scots pine is planted all over the alps. HEP = Switzerland gets 60% of its electricity from alps.
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Volcanoes are found at Destructive and Constructive plate margins. At the destructive plate margin the oceanic plate goes under the continental plate because it's more dense. The oceanic plate moves down into the mantle where it is destroyed. Pool of
magma forms. Magma rises through cracks in the crust called vents. Magma erupts onto the surface (lava) forming a volcano. At constructive plate margins the magma rises into the gaps created by plates moving apart forming volcano.
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Different types of volcano. Composite volcanoes=made up of ash and lava that has erupted, cooled and hardened into layers. The lava is usually thick and flows slowly. It hardens quickly to form steep sided volcano.
Shield volcanoes = made up of only lava. It is runny. Flows quickly and spreads over a wide area forming a low flat volcano. Dome volcanoes=made up of only lava. It is thick, flows slowly and hardens quickly. forming steep sided volcano.
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Volcanic-(case study) soufriere hills in Montserrat June 25th 1997. Primary impacts=Large areas were covered with volcanic material. Capital city plymouth was buried under mud and ash. Over 20 villages and 2/3 homes
destroyed by pyroclastic flows. schools, hospitals and airports were destroyed. 19 people died and 7 injured. Secondary impacts=fires destroyed buildings including locl government offices, the police headquaters and petrol station.
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Tourists stayed away and businesses were destroyed which has negative affect on economy. Population decline. Volcanic ash has improved soil fertility. Tourism is increasing as people come to see the volcano. Immediate response=people were evacuated
from the south to safe areas in north. Shelters were built for evacuees, Temporary infrastructure built like roads and electricity supplies. UK provided 17 million emergency aid. LES provided support services to search for and rescue survivors.
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Long term responses=UK provided 41 million, new docks, an airport and houses have been built.
Supervolcanoes-much bigger than standard volcanoes. They develop at destructive plate margins or over parts of mantle that are really hot called hotspots. YSN in USA is on top of a supervolcano.
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Characteristics of supervolcano= flat unlike normal volcanoes,cover a large area(much bigger than normal volcanoes), Have a caldera (unlike normal volcanoes where there is just a crater at the top) Global consequences=thousands of cubic kilometres of
rock, ash and lava. Thick cloud of superheated gas and ash will flow at high speed from volcano killing, burning and burying everything it touches. Ash will shoot kilometres into the air and block out almost all daylight over whole continents.
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Earthquakes=plates get stuck together and when they become unstuck you get earthquakes. You get earthquate at all plate margins. Destructive=tension builds up when one plate gets stuck as it's moving down past the other into the mantle.
Constructive= tension builds along cracks within the plates as they move away from each other. Conservative=tension builds up when plates that are grinding past each other get stuck.
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The plates eventually jerk past each other, sending out shockwaves (vibration) these vibrations are the earthquake. The shockwave spreads out from the focus - the point in the earth where the earthquake starts. Near the focus the waves are stronger
and cause more damage. Epic centre=the point on the earths surface straight above the focus.
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Earthquakes are measured using 2 different scales: Richter scale=measure ENERGY RELEASED by earthquake called magnitude. magnitude is measured using a seismometer. The mercalli scale=measures the EFFECTS of an earthquake.
Tsunamis= If volcanoes or earthquakes happen at sea they can cause Tsunamis. A tsumami is a series of enormous waves caused when a huge amount of water gets displaced.
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Tsunami-(case study) Indian ocean 26th december 2004. Destructive margin. earthquake measurment=9.1 richter scale. The plate moved very quickly which caused a lot of water to be displaced. 30m high waves.Affected many countries=
indonesia, thailand, india and sri lanka. no early warning systems, 230 000 killed, towns and villages destroyed-1.7m lost their homes, infrastrucure severley damaged, 5-6 million needed emergency food, water and medical supplies.
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economic damage=fishermen lost livelihoods, tourism industry=suffered because people were afraid to go there. Enviromental damage=salt from seawater has meant plants can't grow in many areas. Short term response=hundreds of millions of pounds had
been given by foreign governments, charities, businesses and individuals to give survivors access to supplies and shelter. Ships, planes, soldiers and teams were sent to rescue, clean up and distribute supplies.
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Long term responses=billons of pounds sent to help rebuild infrastructure. programmes to rebuild homes and get people to go back to work. Tsunami warning systems put in place. Management plans= volunteers have been trained so that local people know
what to do if a tsunami happens again.
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Other cards in this set

Card 2

Front

The three types of plate margins are Destructive Margin = two plates are moving towards each other. when an oceanic plate meets continental plate, the denser oceanic plate is forced down in the mantle and destroyed. This often creates volcanoes

Back

and ocean trences (very deep section of the ocean floor where the oceanic plate goes down) Where two continental plates meet, the plates smash together, but no crust is destroyed.

Card 3

Front

Constructive plate margins= where two plates are moving away from each other. Magma rises from the mantle to fill gap and cools, creating new crust.

Back

Preview of the front of card 3

Card 4

Front

Fold Mountains are formed when plates collide at destructive margins. When plates collide the sedimentary rock that has been built up between them are folded and forced upward to form mountains. They form when a continental and oceanic plate collide.

Back

Preview of the front of card 4

Card 5

Front

Case Study-(Alps) They use fold mountains for Farming= steep upland areas are used to farm goats, which provide milk, cheese and meat. Tourism=100 million tourists, 70% tourists visit in the winterand summer to do activities.

Back

Preview of the front of card 5
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