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Canon Slade School

Geography Department

Unit 1 – Physical Geography

Q1. The Restless Earth

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Topic Summary

Plate margins Three types; different movement at each one

Fold mountain ranges and ocean trenches

• World distribution

• Formation

Volcanoes

• World distribution

• Formation of composite and shield volcanoes

• Effects on people: (a) Primary and secondary (b) Positive and negative

• Responses of people: (a) Immediate and long-term (b) Monitoring and predicting

Earthquakes

• World distribution

• Formation, features and measurement

• Effects on people: primary and secondary

• Responses of people: (a) Immediate and long-term (b) Predict, protect and prepare

Case study: one range of fold mountains

• Location and cause

• Opportunities for people (e.g. farming, mining, HEP, tourism)

• Problems (e.g. steep relief, poor soils, limited communications)

• Adaptations of people to overcome them

Case study: a volcanic eruption

• Location and cause

• Effects on people (primary and secondary) (positive and negative)

• Responses of people (immediate and long-term)

• Monitoring and prediction

Case study: two earthquakes 1 Rich country; 2 Poor country

• Locations and causes

• Effects on people (primary and secondary)

• Responses of people (immediate and long-term)

• Contrasts in effects and responses between the two

Special studies

(a) Supervolcanoes

• What could be the global consequences of an eruption?

• Can people do anything?

(b) Tsunamis

• What causes them?

• Why can their effects be so great?

• What can people do?

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Checklist for revision

Understand and know

Need more revision

Do not understand

I can name several large plates forming the Earth’s crust.

I know the differences between destructive, constructive and conservative plate margins.

I can describe the world distribution of young fold mountains and ocean trenches.

I can describe, compare and explain the characteristics of composite and shield volcanoes.

I can state two differences between supervolcanoes and other volcanoes.

I can give the effects of volcanoes on people using these headings – primary, secondary, positive, negative.

I know the main characteristics of earthquakes (focus, epicenter, shock waves).

I know the difference between the Richter and Mercalli Scale.

I can explain why earthquakes cause more loss of life in poor than in rich countries.

Case studies

Fold mountains – I can name one mountain range, explain its formation, give some of the physical problems for people, and know about four human activities found there.

Volcanic eruption – I can name an example, explain how it was caused, state its effects (good and bad) on people, and write out what people have done (their responses).

Earthquakes in both rich and poor countries – I can explain why the earthquake happened there, I can write about the damage and destruction (effects) that resulted, and what was done after the quake.

Tsunami – I can explain the cause of the Asian tsunami, I can name some of the places affected and the damage it did (the effects), and describe how people responded to the disaster.

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Important keywords Keyword Definition Acidic lava Lava with a high viscosity due to the high silica content formed at

destructive plate margins. Produces composite volcanoes. Basic lava Lava with a low viscosity due to the low silica content formed at

constructive plate margins. Produces shield volcanoes. Composite volcano An explosive volcano with steep sides formed by acidic lava at a destructive

plat margin. Constructive plate

margin. Where convection currents in the mantle move two tectonic plates apart. Oceanic crust is forced away from oceanic crust to form ocean ridges. Shield volcanoes/ volcanic islands e.g. Iceland are formed as a result.

Conservative plate margin.

Where convection currents in the mantle move two tectonic plates in the same direction. Here there is great pressure as friction builds between the

plates and movement creates powerful earthquakes e.g. San Andreas Fault, California.

Continental crust Thicker, less dense crust made up of a variety of sediments. Destructive plate

margin. Where convection currents in the mantle move two tectonic plates together. Oceanic crust is forced below continental crust into a

subduction zone. This forms an ocean trench. Earthquake Shaking of the ground.

Effects Primary (first effect) and secondary (after effects). Can be positive and negative.

Fold mountains Long, high mountain range formed by up folding of sediments at destructive (collision) margins.

Hazard Short term events that threaten lives and property. Mercalli scale A scale that measures the effects of an earthquake using eye witness

reports. Observations can be in the form of words or photos on a scale of I – XII.

Oceanic crust Denser crust found in the oceans. Made of basalt and much younger than continental crust because it can be destroyed and renewed at subduction

zones. Ocean trench Landforms found in a linear pattern along subduction zones at destructive

margins. Responses Actions immediately after the event or in the long – term.

Richter Scale A scale that measures the amount of energy released by an earthquake (magnitude). It is measured using a seismometer and it's a logarithmic scale

without an upper limit. Shield volcano A wide – based volcano with gentle sides formed by basic lava at

constructive plate margins or at hotspots. Supervolcanoes A volcano that when it erupts can produce 1000km3 of material. Likely to

have worldwide effects. Tectonic activity Movement of the large rock plates of the Earth’s crust.

Tsunami Giant sea wave travelling at high speed formed by underwater tectonic activity.

Volcano Cone – shaped mountain formed by surface eruptions of magma from inside the Earth.

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Case Studies Case Study of a range of young fold mountains: The Alps (Europe) Location: Central Europe – they stretch across Austria, France, Germany, Italy, Liechtenstein, Slovenia and Switzerland. Formation: formed about 30 million years ago by the collision between the African and Eurasian plates. Tallest peak: Mont Blanc at 4810m (Italy/ France) Population: 12 million people. Human activities within the Alps Farming Farmer practice transhumance – seasonal movement of animals. Fodder crops are grown in the summer for animals and then stored for the winter. Sunnier slopes have been terraced (step – like features) for viticulture (grapes).

Hydroelectric power Narrow valleys are dammed to generate HEP e.g. the Berne area of Switzerland (The Swiss receive 60% of their electricity from HEP). High levels of precipitation mean that reservoirs are constantly replenished.

Forestry Coniferous trees cover many of the slopes, especially north- facing ones. Wood as a plentiful resource, has always been the main building material and winter fuel in Alpine lands. Most sawmills are located on the valley floors near to rivers; timber that cannot be used for construction is made into pulp and paper.

Tourism Visited by 100 million tourists a year. Steep slopes and reliable snow allow winter sports such as skiing in towns such as Chamonix (France). Ski resorts are built on the High Alp (e.g Les Deux Alpes, France) usually on the sunnier south facing slopes. Summer tourism is important. There are large glacial lakes and beautiful mountain scenery in place such as Lake Garda, Italy).

Problems of living in fold mountains such as the Alps § Due to the high altitude, temperatures are cold so it is difficult to grow crops all year round. § The narrow valleys and steep slopes make it difficult to build settlements and there is little

space for farming. § Soils on mountain sides are too stony, thin and infertile. § Areas are often affected by rock falls, avalanches and bad weather. § The narrow valleys and steep slopes make it difficult to build roads and railways.

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How have people adapted to the conditions in the Alps. • Modern roads have been covered to protect against avalanches e.g. St Gotthard Pass between

Switzerland and Italy. • There are electrified railways that link valleys with large cities. • Higher level (high alp) pastures are used for summer grazing. • Animals are kept on the high alp in the summer and moved down to the valley floor in the

winter (transhumance). • Farmers grow crops on the valley floor in the summer and store them for the winter (fodder

crops). • Tunnels have been built through mountains to improve road communications e.g. Mont Blanc

Tunnel. • Settlements are built on south facing slopes because they are warmer. • Ski resorts are built on the high alp and connected to the valley floor via cable cars e.g.

Chamonix. • Crops are grown on the flat valley floor where the soils are thicker and more fertile.

Case Study of a volcanic eruption: Soufriere Hills, Montserrat (1995-1997)

Location Background Information • Montserrat is a tiny island in the Caribbean (100

km2) • Until 1995, very much an ‘island paradise’ (and some

parts still are) with an economy based on farming, fishing and tourism.

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

• Montserrat is classed as a ‘British Overseas Territory’, originally occupied by Irish settlers in 1632. It has its own government but the official head of state is The Queen and it retains strong links to the UK.

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Causes In July 1995, Soufriere Hills erupted for the first time in 350 years. One month later, 50% of the island were evacuated to the north of the island away from the danger zone. In April 1996, Plymouth became a ghost town as more people were evacuated. The deadliest eruption happened in June 1997 when explosive eruptions killed 23 people. Only 39km2 was considered safe. The volcano was largely dormant for the best part of 100 years before the major eruption of 1995-1997. Montserrat lies on a destructive plate boundary where the North and South American plates are sliding beneath the Caribbean Plate (subduction zone). The rising magma forms a chain of volcanic islands called a volcanic arc. Effects Short term:

• 23 deaths and over 100 injured. • Plymouth (capital) covered in ash. • High % of homes, businesses and

important infrastructure destroyed. • Main airport and port closed • 75% of the island was covered in ash.

Long term: • Long time taken to rebuild homes and vital

infrastructure e.g. roads, telephone lines. • Ongoing problems of respiratory disease. • Environmental damage to beaches, forests,

wildlife and offshore coral reefs. • Population fell from 12,000 in 1995 to 1,500

by 2001 (now slowly starting to rise again). • Serious skills shortage due to emigration. • Fears of over-dependence on UK ‘handouts’.

Wider Impacts • Economy (farming, fishing and tourism) decimated, very high levels of unemployment (>50%). • Serious impact on tourism, but visitors numbers starting to recover (‘volcano tourism’) – last

year tourism earned the island over £12m. • Evacuees living for a long time in cramped, unhygienic conditions in ‘temporary’ camps. • Housing shortages leading to a 70% increase in rents – further hardship for islanders. • Ongoing minor eruptions with more serious lahars following heavy rains.

Responses • 5,000 people evacuated to the safe zone to the north of the island from towns such as Salem

and Plymouth. • Links with the UK proved vital in assisting the relief and recovery. • Royal Navy sent ships to evacuate 4,000 people to nearby Antigua. • Islanders were offered £2,500 each to relocate to live permanently in the UK. • UK sent £41m in relief aid and a further £75m to assist long term development. • NGOs like the International Red Cross were important in organising evacuation camps. • Permanent monitoring stations measuring volcanic activity all over the island. • The island is promoting ‘volcano tours’ in an effort to attract tourists back to Montserrat.

However, only 20- seater planes are allowed to land at the new airport so this is proving difficult.

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Case Study of the likely effects of a supervolcano eruption – Yellowstone, USA Local effects

• 1 in 3 people will be killed within 1000km of Yellowstone. • 10,000km of land would be destroyed. • Up to 15cm of ash would cover all buildings within 10,000km making some collapse. • Planes would be grounded and road transport would be difficult. • There will be a large ash cloud rising 40-50km into the atmosphere. • Livestock would choke in hot ash. • Within 1000km of the eruption, 87,000 people could die.

Global effects

• Ash would arrive in Europe up to 5 days after the eruption making temperatures fall between 120C and 150C.

• Parts of Europe and Asia would see constant snow cover for 3 years. • Ash will circle the planet. • Monsoon rains would fail in Asia • 40% of the world’s population could face starvation.

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Comparing the effects of earthquakes in rich and poor parts of the world

Characteristics of the L’Aquila and the Kashmir earthquakes Characteristic L’Aquila, Italy (rich part of the

world) Kashmir region, Pakistan (poor part of the world)

Date 6th April 2009 8th October 2005 Magnitude 6.3 on the Richter Scale 7.6 on the Richter Scale Specific cause Movement along a north- south fault

line close to the destructive plate margin between the Eurasian and African plate.

Movement along a fault line close to the destructive margin where the Indo-Australian plate is squashing into the Eurasian plate.

Time 3.32am (local time) 8.50am (local time) Focus 8.8 km deep 26 km deep Epicentre Close to L’Aquila Close to Muzaffarabad in Kashmir Preparation for earthquakes in L’Aquila and Kashmir L’Aquila, Italy (rich part of the world)

• There are laws on construction standard, but some modern buildings hadn’t been built to withstand earthquakes.

• Italy has a Civil Protection department that trains volunteers to help with things like rescue operations.

Kashmir region, Pakistan (poor part of the world) • No local disaster planning was in place. • Buildings were not designed to be

earthquake resistant. • Communications were poor. There were few

roads and they were badly constructed.

Kashmir region, Pakistan

L’Aquila, Italy

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The effects of the earthquakes in L’Aquila and Kashmir Location L’Aquila Kashmir Primary effects

• 290 deaths (mainly by collapsed buildings)

• 1500 injuries • A bridge near the town of Fossa

collapsed • Many buildings collapsed e.g. the

historic L’Aquila Cathedral and the San Salvatore hospital.

• An area of 1000km2 was affected by surface ruptures

• 80,000 deaths mostly caused by collapsed buildings

• 100,000 people injured • Whole villages destroyed. For example,

80% of the town of Uri was destroyed. • The earthquake affected an area of

about 30,000km2.

Secondary effects

• People treated in makeshift tents due to the collapsed hospital.

• A broken water pipe near Paganica caused a landslide.

• $15 billion worth of damage Aftershocks hampered rescue efforts.

• Hundreds of people were made homeless.

• Fires in some collapsed buildings caused more damage.

• 3.3 million people were made homeless • Due to the freezing winter conditions

shortly after the earthquake, many people died of pneumonia.

• Diarrhoea and other diseases spread due to little clean water.

• $5 billion worth of damage • Water pipelines and electricity lines

were broken, cutting off supply. • Landslides buried buildings and people,

blocking access roads and cutting off water supplies. Emergency services only arrived to help people weeks after the earthquake.

The responses to the L’Aquila and Kashmir earthquakes L’Aquila Kashmir Immediate responses • Camps quickly set up for homeless people

with water, food and medical care. • Ambulances, the army and fire engines were

sent to rescue people • Cranes were used to lift rubble. • Money was provided to pay rent, and

electricity bills/ mortgages were suspended.

Immediate responses • People were rescued by hand without any

equipment or help from emergency services. • Tents, blankets and medical supplies arrived

within a few weeks. • International aid paid for search equipment

and rescue dogs.

Long term responses • By the end of 2009, 4500 new buildings had

been built to house 12,000 homeless people. • The Civil Protection Department will train

more volunteers to help in rescue operations. There are now tougher building laws.

• Six seismologists and a government official sentenced for manslaughter in 2012 for saying to locals that there wouldn't be an earthquake in the area.

Long term responses • Around 40,000 have been relocated to a new

town from the destroyed Balakot. • Training will now be provided to help rebuild

more buildings as earthquake resistant. • New health centres have been set up in the

area.

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Case Study of a tsunami: 2004 Boxing Day Indian Ocean Tsunami A tsunami is a large coastal wave. It is a secondary effect of an earthquake (or volcanic eruption)

Causes: • On 26 December 2004 a tsunami occurred in the Indian Ocean. • It was the result of the Indo-Australian Plate subducting below the Eurasian Plate. • It was caused by an earthquake measuring more than magnitude 9. • The earthquake caused the seafloor to uplift, displacing the seawater above.

Effects • A quarter of a million people died. • Two million people were made homeless. • People were swept away in the waters, which arrived rapidly and with little warning. • Thirteen countries were affected, the worst being Indonesia. • Indonesia was hit by the tsunami first. Forty-five minutes later the tsunami reached Thailand. • Mangrove swamps helped to act as a barrier to reduce the energy of the water in some areas. • Short-term aid, such as water purification tablets, temporary housing and medical supplies

were given from international countries. • Islands reliant on tourism and fishing, such as the Maldives, had to rebuild their industries.

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Responses to the Indian Ocean tsunami of 2004 Immediate responses:

People ran away from the sea searching for high ground. People tried to find family that they had been separated from. People were caught unaware – holidaymakers were on beaches in Phuket, Thailand and fled as the wave approached. They tried to get to higher storeys in hotels, out of the way of the wave. In Banda Aceh, the first place to be hit, hospitals couldn't cope and people were left untreated on corridors.

Rescue services and emergency teams were swamped by the scale of the disaster. Injured people were untreated for days as wounds turned gangrenous and conditions worsened. There were many bodies that had to be buried quickly so that disease would not spread. Mass graves were dug, and as a result, people were buried in body bags without being identified by their relatives. Local people posted photographs on missing relatives and friends in the help that people could recognise the missing. There was an immediate response from the international community. Fresh water, water purification tablets, food, sheeting, and tents all poured in as aid. Medical teams and forensic scientists arrived. The UK government promised £75million and public donations of £100 million followed. Long term responses: A year later, the British public had donated £372 million, but only £128 million had been spent by the Disasters Emergency Committee (DEC). There were organisational issues following the collection of such large sums of money. However, rebuilding was progressing and the DEC has spent £40 million on projects in Sri Lanka and Indonesia. There were plans to spend a further £190 million in the second year, building 20,000 houses for 100,000 homeless people. There were concerns about the number still homeless one year on though. Before the tsunami there had been no early- warning system in the Indian Ocean, so there was a push to rectify this. The Indian Ocean Tsunami warning system was set up in June 2006. It consists of 25 seismograph stations relaying information to 26 national tsunami information centres. Scientists are alerted by text message and e-mails are automatically sent within 2 minutes of significant seismic activity. Ensuring people know how to respond and that local authorities have plans in place are essential for its success. In Thailand, education programmes have taught people that if a tsunami occurs, they are to do one of four things:

• Move to higher ground • Move out to sea in a stable vessel • Move to a tsunami shelter • Move to the upper levels of stable buildings.

In Phi Phi Island (Thailand), bilingual tsunami warning signs are common features on beaches and evacuation routes are clearly marked. Stable raised tsunami shelters have also been built to offer sanctuary during the next disaster.