Restless Earth Revision

Paper 1 – Physical Geography

Question 1

What do you need to know?

1. The Earth’s crust is unstable, especially at plate margins. Unique landforms occur at plate margins. (01:17)

2. People use these landforms as a resource and adapt to the conditions within them. (11:33)

3. Volcanoes are hazards resulting from tectonic activity. Their primary and secondary effects are positive as well as negative. (18:19)

4. Supervolcanoes are on a much bigger scale than other volcanoes and an eruption would have global consequences. (26:59)

What do you need to know?

5. Earthquakes occur at constructive, destructive and conservative plate margins. (31:09)

6. The effects of earthquakes and responses to them differ due to contrasts in levels of wealth. (36:56)

7. Tsunamis are a specific secondary effect and can have devastating effects in coastal areas. (45:25)

1. The Earth’s crust is unstable, especially at plate margins. Unique landforms occur at plate margins.

Earth Structure

Earth Structure

Convection Currents

Plates

Volcanoes and Earthquakes

Types of Crust

Types of Crust

Oceanic Continental

Newer – most less than 200 million years old

Older – most over 1500 million years old

Denser Less dense

Can sink Cannot sink

Can be renewed and destroyed Cannot be renewed or destroyed

Plate Margins

Constructive Destructive Conservative Name

Movement

Land changes

Effects

Activity

Apart and spreading

Creates new land by

magma rising

Ridge of new crust

Shield volcano and

earthquakes

Together and destroying

Destroys crust through

heat and friction

Ocean trench and fold

mountains

Composite volcano and

earthquakes

Sliding past

Nothing created or

destroyed

No major changes

Earthquakes only

Destructive Plate Margin

What happens? A continental plate and an oceanic plate are moving towards each other. The oceanic plate is denser (heavier) so, it is forced underneath the continental plate. This is called subduction. The point at which this happens is called the subduction zone. The oceanic plate melts to form magma.

Creating a volcano… The melted oceanic plate rises up through cracks in the continental crust to form a volcano.

Constructive Plate Margin

What happens? The oceanic plates move apart. As the plates move apart (very slowly), magma rises from the mantle. The magma erupts to the surface of the Earth.

Creating a volcano… When the magma reaches the surface, it cools and solidifies to form new oceanic crust. Eventually the new rock builds up to form a volcano.

Conservative Plate Margin

What happens? Here plates slide past each other. The plates eventually become stuck and tension builds up. Eventually this tension and friction is released as they slip past each other in a sudden movement.

Creating an earthquake The shockwaves created from this movement produce an earthquake.

Ocean Trench

Where there is a destructive plate margin and oceanic crust is going below continental crust, an ocean trench occurs. .

Ocean Trench

This is a deep part of the ocean found where the oceanic plate is being sub ducted under the continental plate.

Fold Mountains

Where two continental plates collide or when a continental plate is pushed up by the subduction of oceanic plate you find fold mountains.

Distribution

Formation

As the plates move towards each other the sedimentary rock crumple creating fold mountains with synclines and anticlines.

Layers build up over time to form sedimentary rock. At a destructive plate boundary two plates move towards each other.

Rivers erode material from the land surface and transport it to the sea depositing it at the bottom of the sea.

2. People use these landforms as a resource and adapt to the conditions

within them.

Uses of Fold Mountains

Alps

• The ALPS are located in Central Europe and cover Austria, Italy, Switzerland, Germany and France.

• The Alps consist of many high mountains such as Mt. Blanc, the Matterhorn and Eiger.

• This is also where Europe's great rivers begin such as the Rhine and Danube.

• Around 12 million people live there.

Farming

The valley floor is ideal for farming and the main type is usually is Dairy Farming although vineyards can be found in warmer areas. It is ideal here because: * The land is flatter * The soils are deeper and more fertile * There are better communications Mountain farming takes up 13% of the entire country with around 43,000 Alpine farmers in Switzerland.

Tourism

• 100 million people visit the Alps every year.

• 70% of Tourists visit in the winter • 30% of people visit in the summer. • Entirely new villages have been built

to cater for the vast quantity of tourists (e.g. Tignes in France)

• Ski Runs, Ski Lifts, Cable Cars, Holiday Chalets and Restaurants pepper the landscape.

Forestry

Many trees wold not be able to grow in the harsh conditions and on the steep slopes, to combat this Scots pine is planted all over the Alps because its more resilient.

Forestry employs over 90,000 people in Switzerland with 31% of Switzerland covered in Alpine forest.

Hydro-electric Power

Hydroelectric power is generated by water moving through a dam to turn a turbine; creating electricity. The narrow valleys are perfect for building a dam to generate hydroelectric power. The highest concentration of hydroelectric power stations is in the Berne region of Switzerland. In total, 60% of Switzerland's electricity comes from hydroelectric power stations in the Alps. The Grande Dixence Dam in Switzerland powers four different hydroelectric power stations.

Adaptations

Changes people make to ensure they are able to cope with the conditions they live in.

Steep Relief

• Many farms keep goats because they're well adapted to live on steep mountains and provide meat and milk.

• The steep sides of valleys is perfect to build a dam to create hydroelectric power plants.

• Some farms create steps on steep slopes so they are able to grow crops, this is called terracing.

Poor Soil

• Animals are grazed in the upper-most areas as the soil is thin and un-fertile, which means crops can't be grown very well.

• Low lying slopes are more fertile so only theses areas are used to grow crops, such as vineyards.

Limited Communications

• It is difficult to get around due to all the steep slopes this means that roads are only built over lower sections between mountains, but these can be blocked by snow in winter.

• As the countries are rich problems like communication and transport have been overcome. Modern road tunnels e.g. Mont Blanc, St Bernard have replaced old routes over high passes. Many electrified railways link the Alps to cities; rail tunnels under the Alps include the Brenner and St Bernard.

• Cable cars and ski lifts link the valley floor to high level benches and ski slopes above them.

Natural Hazards

Avalanches and rockslides are two hazards that affect people in fold mountains. There are three ways that these can be prevented. • Explosions Avalanches can be started deliberately in order to prevent the snow building up. This is one of the most important ways of preventing avalanches. • Snow fences and barriers These can be used to divert and break up the path of the avalanche.

• Reforestation Trees can be planted, increasing stability of the slope and helping to reduce the damage further down the valley.

3. Volcanoes are hazards resulting from tectonic activity. Their primary and secondary effects are positive as

well as negative.

Types of Volcano

Composite Volcano

• Composite volcanoes are made up of alternating layers of lava and ash (other volcanoes just consist of lava).

• They are usually found at destructive boundaries. • The eruptions from these volcanoes may be a pyroclastic flow rather

than a lava flow. A pyroclastic flow is a mixture of hot steam, ash, rock and dust.

• A pyroclastic flow can roll down the sides of a volcano at very high speeds and with temperatures of over 400°C.

Shield Volcano

• Shield volcanoes are usually found at constructive. • They are low, with gently sloping sides. • They are formed by eruptions of thin, runny lava. • Eruptions tend to be frequent but relatively gentle.

Distribution

Montserrat

Montserrat is a tiny island in the Caribbean measuring only 12 km N-S and 8 km E-W (100 km2)

Until 1997, very much an ‘island paradise’ (and some parts still are) with an economy based on farming, fishing and tourism.

Relatively poor with average household income of around £2,800 a year.

Montserrat

Do Not Enter

Mt Soufriere Hills Volcano

Capital City Plymouth

Video

YouTube

Montserrat

GCSE

Geography

Case Study

Before/After

Before/After

Key words

Primary Effects: the immediate effects of the eruption caused directly by the eruption.

Secondary Effects: the after effects that occur as an indirect effect of the eruption on a longer timescale.

Primary Effects

• 19 people died after going into the exclusion zone.

• Plymouth - the capital city was buried under 12m of ash and mud.

• Bramble airport and the port in Plymouth were destroyed.

• Farmland was destroyed • Forest fires caused by pyroclastic flows • Many schools and hospitals were

destroyed

Secondary Effects

• Fires destroyed many buildings.

• Tourists stayed away from the island and the economy was disrupted.

• 8,000 of the island 12,000 inhabitants left.

• Volcanic ash will improve soil fertility

• Some tourists come because of the eruption.

Immediate Responses

• People were evacuated from the south of the island to the north.

• Shelters were built for the evacuees.

• The UK provided £17million of emergency aid.

Long Term Responses

• A risk assessment was done to help islanders understand which areas are at risk and reduce problems for the future – creating an exclusion zone.

• £41 million was given in aid by the British Government.

• The MVO (Montserrat Volcano Observatory) was set up to study the volcano and provide warnings for the future

Prediction of Eruptions

• Earthquakes

• Tiltmeters

• Digital Cameras

• Gases Emitted

4. Supervolcanoes are on a much bigger scale than other volcanoes and an

eruption would have global consequences.

Formation

Yellowstone

Yellowstone National Park is located in the states of Wyoming, Montana and Idaho in the USA.

Underneath Yellowstone

National Park is one of

the worlds largest

supervolcanoes.

Possible Effects

• Yellowstone (87,000 predicted deaths) • Ash rise 40-50km into the atmosphere. • 10,000 km of land destroyed. • Flights suspended. • Farmland destroyed. • UK would see the ash cloud 5 days later. • Buildings collapse under the ash. • 40% of population face starvation as crops

fail. • Some parts of Europe would see snow fall.

Differences

Shape

Supervolcanoes are generally flat (caldera) whereas volcanoes are steep sided mountains with a crater.

Scale

Supervolcano would be on a larger scale and much more violent with global effects with thousands of tonnes more material emitted than a volcano.

5. Earthquakes occur at constructive, destructive and conservative plate

margins.

Distribution

Features

Formation

• Two plates at a plate margin cannot move past each other easily.

• The plates become locked together.

• Friction causes pressure to build up.

• Suddenly, the pressure is released and the plates jolt into a new position.

• This causes seismic waves.

• The vibrations they cause are an earthquake.

Measuring

There are two different scales used to measure earthquakes

Richter Scale This measures the MAGNITUDE of an earthquake. This means how much energy is released.

Mercalli Scale This measures the INTENSITY of an earthquake This means the effects of an earthquake

Richter Scale

Mercalli Scale

Prediction

We can try to predict earthquakes, but only on rare occasions is this successful. The odd behaviour of animals and the analysis of foreshocks led to the evacuation of Haicheng in China in 1975, probably saving 150,000 lives.

Protection and Preparation

Video

YouTube

Millions To

Participate In

Thursday's

'Great Shake

Out'

6. The effects of earthquakes and responses to them differ due to contrasts in levels of wealth.

Rich – Kobe Japan

7.2 on the Richter

scale.

The epicentre

was 12 miles from

Kobe.

Video

YouTube

Great Quake

Kobe

Effects

• 6434 People died • 340,000 people affected by the quake and 300,000

of those were made homeless • 2 million homes were without electricity and 1

million without water for 10 days • The great Hanshin Expressway

collapsed. • Fires spread and were impossible

to extinguish because of blocked roads and broken water pipes.

• The quake caused $220 billion in damages.

.

Immediate Responses

• Japanese government evacuated people to temporary shelters

• Fire and emergency services searched for survivors

• Hospitals treated the injured

• Motorola maintained phone connections free of charge

• Bulldozers brought in to clear fallen buildings

Long Term Responses

• Most rail connections repaired within a month

• Port back in operation within a year • Roads repaired within 6 months • New buildings built to modern ‘earthquake-

proof’ specifications (as older buildings had collapsed)

• High rise buildings have steel frames • Japanese now practice an earthquake drill

every year

Poor - Haiti

7.0 on the Richter

scale.

The epicentre

was 15 miles from

the nation’s capital,

city Port au Prince.

Video

YouTube

The week in

Haiti

Effects

• 230,000 dead. • Over 1 million homeless. • Estimated that 150,000

residences and 30,000 commercial buildings had collapsed or were severely damaged.

• The presidential palace was destroyed.

• 5,000 schools were damaged or destroyed.

• Roads were also very badly damaged and hindered aid efforts.

• 1 in 5 jobs lost as a result of the earthquake.

• Water became contaminated and 7,000 died from cholera related to dirty drinking water.

• Sewage and other substances leaked into the sea killing wildlife.

• $11.5billion worth of damage.

Short Term Responses

• Individuals tried to recover their belongings. • Search and Rescue from other countries • The actual aid effort was almost non-existent

from within Haïti as its institutions had been destroyed or did not have the resources to cope.

• Relied on the USA and Dominican Republic to supple food, water, medical supplies and shelters.

• UK Disasters Emergency Committee raised over £100million

Long Term Responses

• The EU gave $330 million and the World Bank waived the countries debt repayments for 5 years.

• 6 months after the quake, 98% of the rubble remained uncleared; some still blocking vital access roads.

• Between 23 major charities, $1.1 billion had been collected for Haïti for relief efforts.

• ¾ of damaged buildings were inspected or repaired.

• 200,000 people received cash or food for public work like clearing the rubble.

Why did Haiti Suffer?

• Is incredibly poor – most people survived on less than $2 a day.

• 80% of people lived in poorly constructed buildings – concrete that easily crumbled with no building regulations.

• The earthquake was close to the city. • Infrastructure such as the port and airport made it

hard to bring in supplies. • A lack of doctors and medical facilities meant many

died from easily treatable injuries or disease. • An unstable government meant that there was a

lack of coordination in rescue and recovery efforts.

7. Tsunamis are a specific secondary effect and can have devastating

effects in coastal areas.

Formation

Japan 2011

Video

YouTube

BBC News

Panorama

Documentary

Japan

Tsunami

Cause

The earthquake occurred at a shallow depth of just 20 miles below the surface of the Pacific Ocean. This, combined with the magnitude of 9.0 caused a tsunami.

Effects

• More than 20,000 people officially dead or missing, with many more unaccounted for, including 9,500 people in one town.

• The port of Sendai was totally destroyed.

• Radiation leaks from the damaged Fukushima nuclear plant after an explosion blows off the roof, raising fears of a meltdown at the nuclear power station.

• 500km2 of land was submerged by waters and debris.

• Some 215,000 people living in government shelters.

• Six million homes without power, a million with no water.

• Experts say the total insured loss could be up to $15bn.

Responses

• 100,000 Japanese soldiers were deployed in search and rescue.

• Exclusion zone was set up around the Fukushima nuclear plant evacuating people from the area.

• One year after the tsunami all of the debris had been removed from the affected areas.

• Huge re-building and reconstruction programme was put under way.

• Tsunami walls have been re-built to be higher than the usual 12m.

Restless Earth Revision

Paper 1 – Physical Geography

Question 1