Geography Revision Cards

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  • Created by: mkindell
  • Created on: 18-05-15 17:49

Earthquake Mitigation

Earthquake drills

  • practice what happens in an earthquake --> emergency services --> schools

Emergency kits

  • kept in case of an earthquake (food, water, blankets, torch, radio --> not preventative but useful

HIC Earthquake proof buildings

  • taller building, deep foundations, rubber shock absorbers, double glazing, steel frame

LIC Earthquake proof building

  • wooden cross bracing, steel rod foundations, thatched roof
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Dynamic

Dynamic - a force that stimulates change or progress within a system

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Sustainable

Sustainable - meeting the needs of the present without comprimising the needs of the future (using resources carefully

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Layers of the Earth ("spheres")

Atmosphere

  • Layer of gases which make up the air around us
  • oxygen - humans need to respire, CO2 - plants need to photosynthesise

Hydrosphere

  • Layer of water on the earths crust
  • water cycle, water for plants & animals

Biosphere

  • layer of living organisms (on the earth's crust)
  • live on & survive, food & water, organisms used for medicines

Geosphere

  • layer of rock (earths core-crust)
  • cores magnetic field protects us from space radiation, minerals, fossils, fuel, building materials

the four layers interact throught the hydrological cycle

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Earth's Structure

Inner Core

  • solid layer made from iron
  • 5500 degrees centigrade

Outer core

  • liquid layer of iron

Mantle

  • thick semi-solid layer
  • 1300-5000 degrees centigrade

Crust

  • solid outer layer
  • 6-70km deep

Lithosphere = the crust and upper layer of the mantle, split into tectonic plates, solid, cooler

asthenosphere = upper layer of the mantle below the lithosphere, semi-solid, hotter

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Constructive Plate Boundary

Example: Mid Atlantic Ridge (Iceland - Volcano)

  • Two oceanic plates move apart
  • magma rises to fill the gap and cools, forming land
  • creates volcanoes --> earthquakes

Iceland's land mass is increasing as the plates move apart

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Destructive Plate Boundary

Example: Andes Mountains

  • Continental plate meets an oceanic plate
  • the oceanic plate is subducted underneath the continental plate because it is more dense
  • as the oceanic plate is subducted it is heated and melts forming magma --> increased volume of magma causes pressure to build --> leads to volcano(es) forming & volcanic eruptions
  • friction between the moving plates can cause earthquakes
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Conservative Plate Boundary

Example: San Andreas Fault

  • two continental plates rub against each other either in different directions or in the same direction at different speeds
  • friction causes small tremors
  • large slips cause larger earthquakes
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Collision plate boundary

Example: Himalayas, The Alps (african plate colliding with Eurasian plate)

  • two continental plates of similar depth and densities meet meet and force each other upwards / ground between them buckles under pressure --> creates fold mountains
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Convection currents

mantle - earths layer in which convection currents occur

plumes - magma rising

convection cell - a singular current of magma

convection current - a circular flow of magma in the mantle

  • magma in the mantle is heated by the earths core
  • a plume of magma rises
  • as it reaches the earths crust it cools and solidifies slightly, begins to sink
  • this creats a convection cell/convection current - a circular flow of magma from the core to the crust then back down to the core
  • this circular movement moves the tectonic plates (continental drift)
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Volcanoes Key words/info

eruptions measured in VEI (Volcanic explosive Index) on a scale of 1 - 8 (least - worst)

Volcano - an opening or vent in the earth's surface through which molten magma erupts and solidifies as lava

Active - currently erupting (erupting often)

Dormant - not currently erupting but due to erupt in the future

Extinct - no longer erupting(/active)

viscosity - thickness (of lava - high viscosity = thicker, more solid lava)

crater - the volcano's opening

vent - the passage by which the magma exits

magma chamber - area within the volcano body containing magma

predicted by monitoring earthquakes or gases escaping from vent/crator

prevention/reduction of effects - shelters, emergency supplies, evacuation, refugee camps, rescue missions, aid

 

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Volcanic Eruption Effects

Primary effects - happen immediately (during eruption)

  • lava flows
  • acid rain
  • poisonous gases
  • ash cloud
  • pyroclastic flows
  • volcanic bombs

Secondary effects - delayed, occur as a result of the eruption

  • food & water shortages
  • evacuation / refugee camps
  • loss of homes
  • livestock / crops destroyed
  • disease spreads (e.g. cholera)
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Volcano Types

Composite Volcano - larger, steep slopes, more powerful eruptions, more layers of cooled ash and lava, high viscosity, usually formed on destructive plate boundaries (e.g. Sakurajima, Japan)

shield volcano - smaller, rounded / less steep, weaker eruptions, high viscosity, lava and ash flows slower and further, usually formed on constructive plate boundaries (e.g. Icelandic Volcano)

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Earthquakes

earhtquake - a sudden violent movement of the earth

  • occur after a build up of pressure causes rocks to give way
  • measured using a seismograph, on the richter scale
  • mostly occur on plate boundaries and after volcanic eruptions

Can be caused by:

  • nuclear testing
  • drilling for oil
  • coal mining
  • weight of large dams
  • fracking

focus - the point below the earths surface (inside the crust) where the pressure is released

epicentre - the point on the earth's surface directly above the focus, where the most movement is felt

shallow focus earthquake - an earthquake with a focus near to the earths surface (more severe)

deep focus earthquake - an earthquake with a focus deep in the earths surface (less severe)

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Climate

Climate - The average weather of an area over the past 30 years 

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Weather

Weather - climate on a day-to-day basis (e.g. temperature, rainfall)

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Understanding Past Climates

  • Ice age/glacial periods - interglacial periods
  • fossils
  • landforms (e.g U-shaped valleys left by glaciers)
  • Ice cores
  • carbon dating
  • human records (photos, diaries, harvest records, paintings)
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Eruption Theory (change in climate)

Large volcanic eruptions produce ash clouds

wind causes the ash cloud to spread around our atmosphere

ash ---> blocks out suns rays

sulphur dioxide --> global cooling

Example: Mount Pinatubo, Philippines 1991 eruption released 17 million tonnes of CO2 and Sulfur Dioxide reducing global sunlight

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Sunspot & Solar Output

dark spots on the sun release a larger amount of solar energy

cooler periods, such as the little ice age, and warmer periods have been caused by changes in sunspot activity

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Greenhouse Gas

the natural GHE (greenhouse gas effect) is essential

  • layer of gases (e.g CO2, Methane
  • reflect some sunlight and traps the rest in the earths atmosphere --> keeps global climate constant
  • enhanced GHE caused by industrial revolution ---> rising population --> more people using fossil fuels etc, more farms (cows produce methane)
  • thicker layer of gas traps more solar energy in the earths atmosphere for longer --> increase in global climate (--> ice melts --> water levels rise)
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Global Effects of Climate Change

Advantages

  • mediterranean summers
  • more coastal cities
  • season times increase
  • change in crops
  • temperatures rise by 1-2 degrees

Disadvantages

  • major cities at risk of flooding
  • some areas become drier OR wetter --> crops die
  • preventative flood measures costing £10 billion (UK)
  • greater risk of forest fires
  • loss of Coral reefs
  • increase in tropical diseases
  • glacial melting --> sea levels rise
  • extinction of animals --> upset in food webs
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Ecosystems

ecosystem - a community of plants and animals (biotic) that interact with each other and their physical environment (abiotic - e.g light, water, energy, rocks, minerals, air)

small scale / large scale - large scale are called biomes e.g. Deserts, Rainforests, Tundra

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Factors affecting Biomes

  • Latitude - angle affects the way the suns rays hit the earths surface, more vegetation in the tropics than at the poles
  • continetally - land: quick to heat/cool, water: slow to heat/cool --> land has more extreme climates, marine biomes less extreme
  • altitude - atmosphere is thinner at high altitude & temperature is colder --> fewer plants and animals able to survive at high altitude
  • temperature
  • precipitation - where air is forced to rise (low pressure) i.e. at the equator - more precipitation --> rainforests / tropical climate
  • geology - permeable rock absorbs water --> drier climate --> less water for vegetation
  • drainage - areas drained by rivers are drier
  • Soil - where soil is thin/lacking in nutrients its harder for plants to grow
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Biosphere Goods & Services

Goods - physical items that can be removed and used for personal / commercial use

  • medicine
  • wood/timber
  • fruit & nuts

Services - regulating/mainting something

  • nutrient cycle
  • provides habitat
  • regulates atmosphere
  • water cycle
  • carbon cycle
  • Tourism
  • maintaining soil
  • "Green lungs"
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Conserving the biosphere (sustainability)

sustainable management - limiting harm to the environment to reach the meet the needs of the people now and in the future (Economy, Social equality, Environment)

National Parks - 15 in UK, prevent damage to rural areas

Ecotourism - tourism that doesnt damage the environment, e.g. in the rainforest, coral reefs, safaris

RAMSAR - set up in 1971, protects wetlands

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Keystone (species)

Keystone (species) - a species that has a large effect on others, e.g. bees pollinate flowers 

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Sustainable management (Logging)

  • Selective logging - some tree cover remains to protect soil, vegetation, animals
  • extractive reserve - rubber, nuts
  • Agroforestry - crops grown beneath the shade of trees, maintains biodiversity in agriculture
  • Afforestation - seedling nurseries planted in areas of deforestation
  • Eco-tourism
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Uses of Water

  • more technology (e.g. showers, baths)
  • sewage
  • irrigation --> watering crops
  • Industrial uses --> cooling in nuclear power plants
  • Dams --> energy production
  • Attractions (e.g. fountains, water parks)
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Problems of Over-abstraction

  • nature - fish die, vegetation, more pollutants as water volume decreases so less dilute
  • humans - drought --> hose pipe bans, increase in water prices
  • LIC - not enough water --> people drink dirty water --> disease (e.g. cholera) --> people die
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Coral Reefs

  • groups of living organisms found in marine waters
  • vital to humans for: medicines, fishing, tourism, research, aquarium trade, education
  • mostly between tropic of cancer / capricorn in water of 25cm deep or less
  • Coral reefs require very specific conditions of light, oxygen, clear water and a temperature of between 23-29 degrees centigrade
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Threats to Coral Reefs

  • overfishing - upsets eco-system
  • coastline industrialisation - siltation --> blocks out sunlight
  • temperature rise --> coral bleaching, --> ice caps melt --> deeper water
  • volcanic eruptions --> sulfur dioxide melts ice caps --> sea levels rise --> deeper water
  • Tourism --> trampling, tourist food, souvenirs
  • Pollution --> ruins water quality
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difficulties in managing the fishing industry

  • opinions vary
  • many people make a living by fishing and would struggle to earn money any other way
  • its difficult to monitor boats
  • its hard to quantify a catch (overfishing prevention)
  • fishing quotas are controversial as many dead fish are dumped if a catch goes over the limit
  • some people live mostly off fish, stricter fishing regulations mean less fish available (especially specific species) --> prices rise
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River Transport Processes

Traction - large rocks are rolled along the river bed by the current

Saltation - smaller rocks bounce along the river bed

Suspension - sediment carried by the current

Solution - dissolved rock particles carried by the current

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River Courses

Upper course - near the source, starts high, steep

  • features: V-shaped valley, interlocking spurs, waterfalls
  • cross-section: shallow, round, rough - vertical erosion cutting downwards
  • transport: traction, some saltation
  • human use: dams, sheep farming

Middle course - less steep

  • features: meanders, slip-off slopes
  • cross-section: flatter, broader - lateral erosion, some vertical
  • transport: saltation, some suspension
  • human use: clutivated land, occaisional market towns

Lower Course - near mouth, flat

  • features: ox-bow lakes, levees, deltas, mud flats,
  • cross-section: wide, square - lateral erosion, deposition
  • transport: suspension, solution
  • human use: flat fertile land ideal for farming and towns/cities
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Flood Management

Hard = man made

  • Dams
  • Embankments
  • Straightening & Dredging
  • Flood walls
  • Storage areas / balancing lakes

Soft = natural --> sustainable

  • Afforestation
  • Washlands
  • Warning systems
  • Land use zoning
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River Erosion Processes

Hydraulic action - the force of water against a rivers banks

Attrition - material of the rivers load collides with each other and are broken down and smoothed

Corrasion/Abrasion - the load rubs against the river banks as it is carried by the current

Corrosion - acidity of river water dissolves the bed and banks

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