Geography (Physical)
- 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 Volcano - A 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
Restless Planet - Key Words
- Geosynclines - A 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
- Crater - A 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
- Caldera - A 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 Flow - A 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 Scale - A numerical scale for expressing the magnitude of an Earthquake
- Mercalli Scale - A twelve-point scale for expressing the local intensity of an Earthquake.
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.
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.
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.
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.
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.
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.
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.
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.
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
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.
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
Earthquakes - LEDC CASE STUDY
Haiti Earthquake - Responses and Long Term effects
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
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
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
Water on the Land: Key Words
Surplus - An exess of precipitation, exceeds evaporation, resulting in saturated grounds
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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