Geography Paper 1

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Unstable Earth

Constructive plate margins - where plates are moving apart

Conservative plate margins - where plates slide past eachother

Destructive plate margins - where plates collide

Collision zones - type of destructive margin

Oceanic crust - under the oceans (thick)

Continental crust - under continents, land masses (thin)

As heat rises from the Earth's core, it sets off convection currents in the mantle which allows plates to move and is the movement that sets off earthquakes and volcanic erruptions.

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Plate Margins

Constructive

At constructive plate margins two plates move apart; like the North American and Eurasian plates move apart in Iceland (Volcano Eyjafjallajokull). It allows magma from the mantle to rise up to the Earth's surface and make or construct new crust. Earthquakes can also be caused by friction of the plates as they move over the mantle

Destructive

This is wear a oceanic and continental plate collide and as the oceanic is denser than the continental plate, the continental plate sinks beneath into the mantle. When its sunk in the mantle it melts forming magma. It also takes sea water down with it making it less dense in the mantle. This will rise up through the continental crust and explode as a volcanic eruption. The sea water turns into steam. The friction can also cause earthquakes

Conservative

As the plates move past eachother the friction between the plates causes earthquakes. These are rare but can be destructive if the earthquakes occur close to the earth's surface. 

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Landforms at plate margins

Fold Mountains                                                                                                                 They lie on a collision zone and the two continental plates are pushing againist eachother. As they are the same density neither sink, so they push upwards forming fold mountains

Ocean Trenches                                                                                                          

Ocean trenches are also found on destructive plate margins as the denser plate sinks below the continental plate it creates a deep-sea trench

Composite Volcanoes                                                                                                     Found at destructive plate margins, when the oceanic plate sinks into the mantle and melts with the sea water, then rises up through the cracks in the earth's crust forming volcanoes. Eruptions are violent, they are also layered of ash and lava with a tall cone shape

Shield Volcanoes

Found at constructive plate margins as the plates move apart the magma rises up from the mantle, these are non-violent erruptions and have a wide base and gently sloping sides

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Using Fold Mountains - The Alps

Located in Central Europe covering Austria, Italy, Switzerland, Germany & France             Created when the African plate collided with the Eurasian plate

Uses:

Farmers farm cattle on the valley floors and goats on the steep edge of the mountains, they also have vineyards on the sunny side of the mountains to bring money to the economy          

Tourism is a popular use of the Alps with winter sports e.g. skiing and also having locals and visitors supporting the tourism industry, giving an income to the locals. In summer they offer walking and climbing of the mountains                                                                                

Energy companies use the steep terrain and build dams across valleys to provide 60% of Switzerlands power through HEP

Trees are chopped down for the lodges for tourism meaning they have access to cheaper materials

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Using Fold Mountains - The Alps 2

How have people adapted?

Farmers adapted their practise to working in fold mountains by placing goats on steep terrain and moving cows in the summer up to the peaks of the mountains, producing local goods sold to tourists leading to a higher income

A larger use of the alps has led to infrastructure being improved making it easier to access the alps so people can live and work more effectively. They have placed ski lifts and cable cars to move people and cattle

Tourism has developed as locals developed new ways of activities for the resort throughout summer as well as winter providing jobs for locals

Energy companies placing dams has led to people using renewable energy resources instead of scarce non-renewable resources

The industry use natural resources to provide wood for variety of uses. Also providing long term employment

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Volcanic Eruption - Montserrat

Montserrat located in the Caribbean Islands                                                                         This volcano is on a destructive plate margin meaning the oceanic plate sunk and was melted       and the magma rised leading to a violent eruption

The effects

More than half of Montserrat became uninhabitable, infrastructure was destroyed including the airport, 19 people died and many people fled from the Island and tourism decreased

Immediate respones

Residents evacuated, population fell to 3500, British government spent money on aid - temporary buildings, charities set up temporary schools and sent emergency food for farm animals

Long term respones

People returned to the island as the population rised to 5000, the population structure changed as many young people left and didn't return and the British government spent £200 million to restore electricity, water and build infrastructure

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Monitoring Volcanoes

How?

Checking changes in shape using electronic tilt meters and global positioning systems

Using seismometers to listen to the rumbling of the volcano as magma flows to the surface

Creating a seismology network to collect information

Measuring sulfur dioxide emissions

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Supervolcanoes - Yellow Stone National Park, USA

How its formed

The magma is blocked from reaching the Earth's surface, the pressure begins to build up, more rock melts and more magma is formed. When the pressure becomes to much the entire surface above the magma chamber is blown away by a huge explosion, forming a caldera

Impacts of an eruption

Magma would be flung 50km into the atmosphere

All life 1000km away or nearer would be killed by falling ash, lava and the force of the explosion

Enough ash would flow out of the volcano to cover the whole of the USA leading to a mini ice age as radiation from the sun would be unable to reach

This means

Crops wouldn't grow, people would starve, economies would collapse and society would not survive

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Earthquake

Features of an Earthquake

When an earthquake occurs the ground shakes violently causing infrastructure and buildings to collapse

This happens when the plates have been stuck and eventually move sending out huge pulses of energy causing shock waves to travel out from the focus (where the earthquake starts) to the epicentre which is the point on the earths surface directly above the focus

Measuring Earthquakes

The Richter Scale

The magnitude of an earthquake is measured. There is no upper limit to this scale

The Mercalli Scale

The scale goes from 1-12 and measures power and effects of an earthquake based on observation

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Chile, 2010

Occured at a destructive plate margin, the magnitude being 8.8

Primary effects

500 killed & 12,000 injured

500,000 buildings damaged

Infrastructure damaged & Airport slightly damaged

Secondary effects

Most of Chile lost power

Water and communications

Fire brokeout at a chemical plant

Chile's copper mines suffered damage - crucial to their economy

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Haiti, 2010

Occured on a destructive plate margin with a magnitude of 7.0

Primary effects

220,000 dead & 300,000 injured

Infrastructure destroyed including the main port

200,000 homes damaged in Port-au-Prince and 1.3 million Haitians left homeless

Secondary effects

2 million Haitians were left without food and water

There were many dead bodies in the street leading to disease - Cholera

Destruction to government buildings meaning the police force collapsed - increased crime

Infrastructure damaged, no aid could get through

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Chile, 2010 - Responses

Immediate respones

In hours floating bridges were arriving from specific countries as the presidents requests for help

The day after the quake route 5 was temporarily repaired so aid could arrive to places

10 days after the earthquake 90% of homes had power and water restored

$60 million was raised to build emergency supplies and shelter (from a national telethon)

Long term responses

A month after the earthquake Chile's government launched a housing reconstruction plan to build 196,000 homes

The huge copper reserves earned plenty of money for the reconstruction so did not have to rely on foreign aid

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Haiti, 2010 - Respones

Immediate responses

Aid was slow to arrive due to infrastructure being damaged

American engineers tried to clear debris at port for aid to get in 

The USA sent ships, helicopters and $100 million in aid

The food aid cluster was set up to feed 2 million

Field hospitals were set up

Long term responses

New homes still need to be built

Haiti is dependent on Overseas aid to recover

Haiti is still not back to the way it used to be

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Haiti & Chile - Prediction, Prepare & Protection

Prediction - Set up tilt meters to see the plate movement

Preparation & Protection (Chile)

Buildings to withstand earthquakes

Earthquake plan was set up in 2002

Government sets up anti-disaster drills

All Chileans know if an earthquake occurs they must 'Drop, Cover, Hold' under a heavy table or doorframe

Preparation & Protection (Haiti)

Haiti weren't prepared as they hadn't had an earthquake in living memory

They had a weak government and little money (poorest country in world)

The homes were not built to withstand earthquakes as they were poorly built and overcrowdered

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Tsunami - Indian Ocean, 2004

A tsunami that occurs in the sea displacing water towards land

The boxing day scored between 9.0 and 9.3 on the Richter scale

Effects

289,601 were killed or are missing & 400,000 people lost their jobs

Homes, crops and fishing boats were destroyed & tourist resorts were hit

Immediate Respones

Clean water, food and tents arrived as aid& $7 billion was donated for the affected countries

The UN's World Food Programme provided food aid for 1.3 million people

Long term responses

There are tsunami warning systems, drills and the countries are restoring mangroves to absorb water and the wave power before it hits civilians

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