Geography (Physical)

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  • Created by: Samantha
  • Created on: 05-04-13 16:50

Restless Planet - Key Words

  • Crust - Outer layer of the Earth
  • Mantle - Liquid melted molten under the Crust
  • Inner Core - Outer Layer of the Core
  • Core - The centre of the Earth
  • Plate Boundaries - Where the Earths plates meet
  • Destructive Margin - Plates pushing together (Oceanic+Continental)
  • Constructive Margin - Plates moving away from each other
  • Conservative Margin - Plates sliding past each other
  • Collision Margin - Plates pushing together (Both Continental)
  • Earthquakes - Shaking of the earth
  • Volcanoes - A land form where molten lava erupts through the surface of the Earth
  • Shield VolcanoA broad rounded Volcano that is built up by successive outpourings of very fluid lava
  • Extinct Volcano -  A volcano that will never erupt again
  • Focus - The point in the Earth where the eruption occured 
  • Epicentre - The point on the Earth, directly above the Focus
  • Conical Cone Volcano - Classic cone shaped Volcano
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Restless Planet - Key Words

  • GeosynclinesA large-scale depression in the Earth's Crust containing a thick series of sediments
  • Fold Mountains - Mountains formed mainly by the folding of layers within the upper part of the Earth's Crust
  • Ocean Trenches - Depressions on the ocean floor, the deepest parts of the ocean
  • Tsunami - A long high sea wave caused by an Earthquake or other disturbance
  • CraterA bowl-shaped opening at the top of a Volcano
  • Main Vent - Where the magma and volcanic ash escape
  • Super Volcano - A volcano with a magma chamber x1000bigger than a normal Volcano
  • CalderaA large volcanic crater
  • Magma Chamber - A large underground pool of molten rock found beneath the surface of the Earth
  • Active Volcano - A Volcano that could erupt at any time
  • Dormant Volcano - A Volcano that hasn't erupted in years but still could
  • Pyroclastic FlowA dense, destructive mass of very hot ash, lava fragments, and gases ejected explosively from a volcano which travels very fast and has a high temp
  • Richter ScaleA numerical scale for expressing the magnitude of an Earthquake
  • Mercalli ScaleA twelve-point scale for expressing the local intensity of an Earthquake.
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Plate Boundaries

Destructive Plate Boundary

Two plates move towards each other. An Oceanic Plate (the denser plate) sinks under a Continental Plate. When the Oceanic plate sinks so far down it melts, turning into magma which is then released through a volcano.

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Plate Boundaries

Constructive Plate Boundary

Two plates move away from each other, due to convection currents in the mantle. Magma rises inbetween the gap, igneous rock is formed when the magma reaches the surface. They are usually found under the sea. Volcanoes have formed under the sea and new islands have been made. 

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Plate Boundaries

Collision Plate Boundaries

Two land plates are moving towards each other, the land between them buckles and moves upwards. This forms fold mountains, no volcanic eruptions happen here, but sever Earthquakes can happen.

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Plate Boundaries

Conservative Plate Boundaries

Two plates slide past each other, without creating or destroying any land. The main effects are earthquakes which can be fairly violent and frequent. As they move past each other they often get stuch, building up great pressure until finally they jolt past each other. It is this sudden jolt that causes the earthquake.

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Volcano Types

Shield Volcanoes

Are made at Constructive Plate Boundaries, as the plates move apart magma rises to fill the gap, a new layer of rock is then built up each time. They are a cone with a wide base, they are made of lava only, they have regular and frequent eruptions and lava pours out with little violence. 

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Volcano Types

Composite Cone Volcano

These are made at Destructive Plate Boundaries. When the plates collide, the denser plate is pushed down, melts and makes a pool of magma, the great heat and pressure forces the magma upwards. They are tall cones with narrow base and steep sides, made of alternate layers of lava and ash, irregular eruptions with dormant periods, violent explosions possible.

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Fold Mountains

Fold mountains are formed from the collision of continental tectonic plates (they are only made with continental plates).Since neither plate subducts under the other one, the colliding plates buckle and then wrinkle and fold. 


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Ocean Trenches

Ocean trenches are formed when a dense ocean plate collides with another ocean plate or a continental plate, the denser plate "sub-ducts", or sinks back into the mantle. Where this sub-ducting plate buckles and sinks into the mantle creates a deep trench in the ocean floor.


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Earthquakes

Why They Occur?

When the tectonic plates rub or collide together at a plate margin,  pressure builds up and then they move, the movement forces waves of energy to come to the earth's surface. This causes tremors and shakes and this is what causes earthquakes.

How They Are Measured?

Richter Scale - The strength, or magnitude, of an earthquake is measured using the Richter Scale. The Richter scale is numbered 0-10.

Mercalli Scale - A means of measuring earthquakes by describing and comparing the damage done on a scale of l to Xll

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Earthquakes - LEDC CASE STUDY

Haiti Earthquake - Basic Facts

  • Date: 12th january 2010
  • Time of Day: 4:53pm
  • Death Toll: 316,000 people
  • Magnitude: 7.0
  • Cause: A release of built up pressure from the North American Plate moving past the Caribbean plate in a conservative plate boundary.
  • It is the 2nd deadliest earthquake known to man.

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Earthquakes - LEDC CASE STUDY

Haiti Primary and Secondary Impacts

Primary

  • Around 200,000 - 300,000 deaths
  • 80% of buildings fell down
  • Cracks in the ground
  • Most people in Haiti used oil lamps because electricity is too expensive, this lead to fires
  • Water polluted

Secondary

  • Temporary 'tent' houses meant diseases spread easily (specifically Cholera) 
  • Mud slides - this caused many deaths
  • Aftershocks went on for about a month
  • Cracks in the ground hard to repair
  • No shipping - unable to trade
  • Difficulty of getting around the country due to cracks
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Earthquakes - LEDC CASE STUDY

Haiti Earthquake - Responses and Long Term effects

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Water on the Land: Key Words

Erosion - A wearing away of the rocks

Attrition - When rocks collide to form smaller rock particles

Solution - Dissolved substances wearing away the rock

Abrasion - When rocks grind together to wear it down

Hydraulic Action - The force of the water wearing away the rock

Transportation - A movement of substances in the river

Solution - When the substances are dissolved in the water and are carried in the water

Saltation - When small pebbles and stones are carried/bounce along the riverbed

Traction - When big stones roll along the river bed

Suspension - When fine/light material gets carried along in the river

Depositation - When the river doesnt have enough energy to carry the material so it drops it

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Water on the Land: Key Words

Cross Profile - A slice across the river

V shaped valley - Carved by rivers, a valley that resembles a V

Source - Where the river starts

Tributary - A small stram that joins the main river

Confluence - Where 2 rivers join 

Meander - A bend in the river

Ox-bow lake - A detatched meander

Waterfall - A drop in the river

Gorge - A deep channel that is formed by a river 

Flood Plain - An area of land that is prone to flooding

Flood - When water spills out of the river onto the land

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Water on the Land: Key Words

Estuary - The area of land near the mouth of the river where there are lots of little streams and the  land is very flat, where the fresh water meets the ocean

Mouth - The end of the river

Long profile - A slice of the river from source to mouth

Levees - Caused by floods, landforms created by deposition

Flood hydrograph - It shows the amount of rainfall and the discharge of the river

Discharge - The volume of water which flows through it in a given time

Impermeable rock - Doesn't absorb water

Permeable rock - Absorbs water

Hard engineering - Man made flood management

Soft engineering - Uses natural systems to manage flooding

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Water on the Land: Key Words

Surplus - An exess of precipitation, exceeds evaporation, resulting in saturated grounds

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Water on the Land: How a River Changes Downstream

LONG PROFILE

The source of a river - upland

River flows over steep slopes

Flows over a series of waterfalls and rapids - highland - hard igneous rocks - ideal for forming these features

Water performs vertical erosion - steep slopes - cut down into river bed - V shaped valleys

River flows towards the mouth - less slopes

Flat land - the discharge will increase as it approaches the sea


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