GEOGRAPHY sec.solihull.sch.uk/AQA-Rivers-Revision.pdf.

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GEOGRAPHY http:// www.langley-sec.solihull.sch.uk/AQ A-Rivers-Revision.pdf

Transcript of GEOGRAPHY sec.solihull.sch.uk/AQA-Rivers-Revision.pdf.

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Restless EarthDistribution of plates; contrasts between

continental and oceanic plates.Destructive, constructive and conservative

plate margins.

1. More dense – heavier

2. Darker

3. Younger

4. Basalt

1. Less dense

2. Lighter (in colour)

3. Older

4. Granit

1. Density2. Colour3. Age4. Rock

Type

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Restless EarthDestructive, constructive and conservative

plate margins.

• oceanic and continental plate move towards each other.

• The dense oceanic plate is forced under the continental plate.

• As it sinks below the continental plate the oceanic plate melts due to friction in the subduction zone.

• The crust becomes molten called magma.

• This may be forced to the surface of the earth causing a volcanic eruption.

• The movement of the oceanic plate is not smooth.

• Due to friction the plate gets stuck. Pressure then builds up.

• The plate will eventually slip sometimes causing an earthquake.

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Mid ocean ridge?

• Plates move away from each

other due to convection currents

in the magma

• Magna rises from the mantle

through the opening.

• The magna erupts to the surface

of the earth.

• When the magma reaches the

surface the lava cools and

creates new crust.

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• Formation of ocean trenches?

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ShieldVolcanoes

Gentle slopes

frequent

Low-wide base coneThin-runny

lava

Non violent

Constructive PB

E.g.. Mauna loa

Composite

VolcanoesDestructiveSteep sidesExplosiveLess frequentMade of alternative layers of ash + lava

Eg mount fuji

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Andes: fold mountain• FarmingGrow crops on low valleys. Cash crops:

• HEP: Hydroelectic actionSteep slopes, narrow valleys = easily dammed. Snow melt increases supplies. El Platinal dam 2nd biggest in Peru • MiningLot of important minable material. Iron, nickel, silver, Gold, Coal, Oil. Mining in Yanacocha is open cast (largest in the world)• Tourism

• The length of the west coast of south America.

• Oceanic and continental crust

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Warning signs Monitoring techniques

Hundreds of small earthquakes are caused as magma rises up through cracks in the Earth's crust.

Seismometers are used to detect earthquakes.

Temperatures around the volcano rise as activity increases.

Thermal imaging techniques and satellite cameras can be used to detect heat around a volcano.

When a volcano is close to erupting it starts to release gases. The higher the sulfur content of these gases, the closer the volcano is to erupting.

Gas samples may be taken and chemical sensors used to measure sulfur levels.

Key techniques for monitoring a volcano

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• Preparing for an eruption• A detailed plan is needed for dealing with a possible

eruption. Everyone who could be affected needs to know the plan and what they should do if it needs to be put into action. Planning for a volcanic eruption includes:

• creating an exclusion zone around the volcano• being ready and able to evacuate residents• having an emergency supply of basic provisions,

such as food• funds need to be available to deal with the emergency

and a good communication system needs to be in place

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EarthquakesPredicting & Preparing

• Seismometer: used to pick up the vibrations in the Earth’s crust. An increase may indicate earthquake.

• Radon gas: escapes from cracks in crust. Sudden increase= earthquake.

• Training: holding drills, education via TV, Radio.

• Emergency kits: stored in homes, tinned food. First aid, blankets.

• Earthquake proof buildings: designed to absorb the energy from earthquake.

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Measuring Tool

Seismograph Observation

Measures The energy released by earthquake

The effects caused by earthquake

Calculation Information resulted from seismometers that measure the shock waves and movement

Quantified from observation of effect on earth’s surface, human, objects and man made structures.

Scale 1 – 10+ I – XII

Richer Scale Mercalli Scale

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San Andreas

Conservative Plate Boundary :

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CASE STUDY: Haiti (LEDC)

EFFECTS

280,000 buildings collapsed =90% of all

16,500 schools damaged

316,000 killed

3m affected

Transport & communication links damaged

Flattened homes= living on the streets n cars.

Huge economy impact

1/5 jobs lost

Roads blocked 10 days after

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CASE STUDY: Japan (MEDC)

EFFECTS

10 trains were derailed

A 500m wall of flame swept through the city

180,000 buildings were damaged.

Thousands trapped in the rubble

5,390 died

Risk of disease-No sewage system &disposal of dead bodies were delayed

After shocks

230,000 homeless

Such as Panasonic were forced to close

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HAITI

Caribbean + N. American plates moving same direction.

Shallow focus of 13km below surface.

Epicentre 16km west of capital, Port-au-Prince.

Seismologists warned of huge earthquake as fault been ‘locked’ for 250yrs.

JAPAN,KOBE