Year 9 Tectonic Hazards Revision Booklet

What do I need to know?

Topic Page Number Tick when learnt Causes of tectonic plate movement

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The four different types of tectonic plate margin

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Describing the distribution of tectonic hazards

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Why do people continue to live in earthquake prone areas?

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The causes of earthquakes at different plate margins

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How can the impacts of earthquakes be reduced

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HIC Earthquake Case Study – New Zealand

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LIC Earthquake Case Study – Nepal

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Practice 9-17

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What causes tectonic plates to move?

The Earth's crust is broken up into pieces called plates. Heat rising and falling inside the mantle creates

convection currents. The plates are ‘floating’ on the mantle and the convection currents move the plates.

Where convection currents diverge near the Earth's crust, plates move apart. Where convection currents

converge, plates move towards each other. The movement of the plates, and the activity inside the Earth,

is called plate tectonics.

What are the different types of plate margin?

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Describing the distribution of tectonic hazards

The 4 Cs

When describing distribution of something you need to say where something occurs and

the way it does – are there any patterns? You need to include the continent that thing

occurs in, the compass direction in that continent, the coastline that thing is on, and give a

country example.

For example: Earthquakes are unevenly distributed around the world. They occur in bands

on tectonic plate boundaries, often on the edges of continents. A number of earthquakes

can be seen on Pacific coast of South America, for example in Chile.

Why do people continue to live in earthquake prone areas?

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What causes earthquakes?

An earthquake is the shaking and vibration of the Earth's crust due to movement of the Earth's plates (plate tectonics). Earthquakes can happen along any type of plate boundary.

Earthquakes occur when tension is released from inside the crust. Plates do not always move smoothly alongside each other and sometimes get stuck. When this happens pressure builds up. When this pressure is eventually released, an earthquake tends to occur.

At a conservative plate margin, the plates move past each other or are side by side moving at different speeds. As the plates move, friction occurs and plates become stuck. Pressure builds up because the plates are still trying to move. When the pressure is released, it sends out huge amounts of energy, causing an earthquake. The earthquakes at a conservative plate boundary can be very destructive as they occur close to the Earth's surface.

A destructive plate boundary occurs when oceanic and continental plates move together. The oceanic plate is forced under the lighter continental plate. As the plates move, friction occurs and plates become stuck. Pressure builds up because the plates are still trying to move. When the pressure is released, it sends out huge amounts of energy, causing an earthquake.

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How can the impacts of earthquakes be reduced?

Despite much research it is not yet possible to predict earthquakes accurately - The best advanced knowledge is 9 seconds which is too short to do anything. Therefore most efforts have been put into preparing for them. Below are some of the ways:

Earthquake Resistant Buildings - These are built with deep foundations with rubber shock absorbers and concrete reinforced with steel. They are designed to twist and sway, have sprinkler systems and gas cut off valves. For example the Transamerica Pyramid in San Francisco, California.

Emergency Plans - These are drawn up, and supplies such as bottled water, medicines, tinned food etc. are stockpiled by individuals or the local area

Earthquake Drills - These are held to practise what to do in the event of an earthquake taking place such as the one held in Japan on Sept 1st every year.

Tsunami Warnings - As Tsunamis occur in the Pacific Ocean there are data collecting devices to give warnings of such an event. They are also being built in the Indian Ocean.

Prediction

Prediction involves using seismometers to monitor earth tremors. Experts know where earthquakes are likely to happen, however it's very difficult to predict when they will happen. Even looking at the timescale between earthquakes doesn't seem to work. Along the San Andreas fault in California, USA, scientists have some of the most advanced technical equipment and education in predicting earthquakes – but they too cannot be exactly sure of when or where an earthquake may strike.

Protection

Many areas prone to earthquake hazards now use building codes. Any new building or adjustment to existing buildings must be built to strict guidelines that would protect people from future earthquake hazards. Protection involves constructing buildings so that they are safe to live in and will not collapse. Some examples of building improvements are:

Rubber shock absorbers in the foundations to absorb the earth tremors.

Steel frames that can sway during earth movements.

Open areas outside of the buildings where people can assemble during an evacuation.

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Low cost methods, such as wire mesh retrofitting, are used in rural areas and developing countries. These are affordable and appropriate to the resources and people living there.

Lightweight roofs and safety glass designed to reduce damage and injury.

Preparation

Hospitals, emergency services and residents practise for an earthquake in earthquake-prone countries. They have drills in all public buildings so that people know what to do in the event of an earthquake. This helps to reduce the impact and increases people's chance of survival.

Responses

Responses are how countries react to an earthquake. They are categorised as follows:

Short-term or immediate response - in the hours, days and weeks immediately after a disaster, it mainly involves search and rescue efforts and helping the injured.

Long-term response - continues for months and years after a disaster and can involve rebuilding damaged or destroyed houses, schools, hospitals, etc. Kick-starting the local economy is also considered a long-term response.

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HIC Earthquake Case Study – Christchurch, New Zealand, 2011

Location

New Zealand is located in the Pacific Ocean in the continent of Oceania. It is South East of Australia and consists of a North and South Island. Its capital city is Wellington.

Causes

The 6.3 magnitude earthquake struck New Zealand at 12:51 on 22 February 2011. The epicentre was 6 miles South East of Christchurch and the focus was very shallow at 3.1 miles. The earthquake occurred on a conservative plate margin where the Pacific Plate slid past the Australian Plate in the opposite direction. It was technically an aftershock from a larger earthquake in 2010 but the impacts were more severe.

Effects

Primary (caused directly by the earthquake) Secondary (result from primary effects)

181 people were killed and around 2,000 people were injured

Business were put out of action for long periods causing losses of income and jobs

Hundreds of kilometres of water and sewage pipes were damaged

Schools had to share classrooms because of the damage to other school buildings

50% + of Central City buildings severely damaged including the city’s cathedral which lost its spire

Damage to roads through liquefaction made it difficult for people and emergency services to move around

Liquefaction (where the ground gets saturated and loses strength) caused lots of damage to roads and buildings

People were affected mentally by the earthquakes and needed support

Part (size of 20 football fields) of the country’s longest glacier was broken off creating a large iceberg

Christchurch could no longer host Rugby World Cup matches so lost the benefits, e.g. tourism and income, they would bring

80% of the city was without electricity

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Responses

Short Term Long Term

Cared for the most vulnerable people and ensured people were safe from dangerous buildings

Paid $898 million in building claims

Chemical toilets were provided for 30,000 residents

Provided temporary housing and ensured all damaged housing was kept water tight

Areas were zoned (green, orange, white, red) to classify damage/cost of repairs

Water and sewerage was restored for all residents by August

International aid was provided in the form of money (around $6-7 million) and aid workers

Roads and houses were cleared of silt from liquefaction by August and 80% of roads/50% of footpaths were repaired

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LIC Earthquake Case Study - Gorkha, Nepal, 2014

Natural hazards

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Key idea: Natural hazards pose major risks to people and property.

1. Define ‘natural hazard’ and give examples.

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

_________________________________________

2. Add the events to the table below. Events: earthquake, volcanic eruption, tsunami,

tropical storm, hurricane/typhoon/cyclone, climate change

Event Meaning Lava erupts from a vent in the earth’s crust. This occurs at destructive

and constructive plate boundaries.

Changes to the earth’s atmospheric patterns, especially rainfall and temperature. These changes vary region to region, but in many places they involve increases in temperature.

Different names are given to tropical storms depending on where they occur.

Shaking of the ground due to tectonic movement. This occurs at all plate boundary types.

A series of fast moving, long and high waves resulting from tectonic movement under the ocean floor.

A powerful storm that moves at more than 74 miles per hour. They form over water and spin in an anticlockwise direction, gathering power as they move over water & losing power when they reach land.

3. Complete the paragraph about hazard risk by filling in the gaps with the provided vocabulary. Vocabulary: equipped, earthquakes, probability, density, magnitude, nature, defences, flooding, rebuild, greater, human, frequently, cope, severe.

Hazard risk is the _____________________ that a natural hazard occurs. To count as a

hazard, the event has to affect _____________________ activities. Several factors influence

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hazard risk. One is vulnerability. The denser the population is in an area exposed to natural

hazards, the greater the risk that they will be affected by a natural hazard. For example, an

area with a high population _____________________ along a very active plate boundary

(e.g. San Francisco) is especially vulnerable to earthquakes, and a densely populated

floodplain (e.g. Bangladesh) is especially vulnerable to __________________ caused by

extreme weather. Another factor is capacity to _____________________. The better a

population can cope with an extreme event, the lower the impact will be. For example, HICs

are often better _____________________ than LICs to deal with the impacts of natural

hazards such as flooding or volcanic eruptions., because they are more able to build

__________________, evacuate people, provide swift medical assistance and

________________ quickly. Another factor is that the _________________ of natural

hazards varies considerably. Some hazards can be predicted (e.g. tropical storms) giving

people and governments time to prepare and evacuate, while others cannot be predicted

and happen suddenly (e.g. _____________________) meaning that people are caught

unaware. Some hazards occur more _____________________ than others, increasing

hazard risk. Some hazards are more _______________ than others, e.g. an earthquake of

9.2 on the Richter scale will have a far _______________ hazard risk than one that registers

in at 4.6. To summarise, some key factors affecting hazard risk are: vulnerability, population

density, capacity to cope, level of preparation, hazard type, hazard frequency, and

_____________________.

4. Would hazard risk be greatest for A or B? In the final column, give reasons for your choice. An example has been done for you.

Question A B Risk would be greatest in… (A or B)

Reasons

Where will economic cost be greatest?

Volcanic eruption in a rural area

Volcanic eruption in an urban area

B

Urban areas have more buildings and businesses so insurance and reconstruction costs would be higher. Replacement of belongings is costly for individuals.

Where will economic cost be greatest?

Earthquake in an urban area in a HIC

Earthquake in an urban area in a LIC

Where will human

A tsunami strikes a densely

A tsunami strikes a sparsely

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cost be greatest?

populated coastline

populated coastline

Where will human cost be greatest?

Rising sea levels- mountainous region

Rising sea levels- small Pacific islands

Tectonic hazards

Key idea: Earthquakes and volcanic eruptions are the result of physical processes.

5. The theory of plate tectonics is that….

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

6. Look at the map. The black lines show plate margins. In one sentence, say what a

plate margin is.

___________________________________________________________________________

___________________________________________________________________________

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7. Why do most earthquakes and volcanoes occur near plate margins? In your answer, try to use geographical terms such as: convection currents, tectonic plates, plate boundaries, collision, energy, etc.

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

_________________________________________

8. Where do more tectonic hazards occur? Circle the correct answers.

a. On or near plate margins / far from plate margins

b. Near the Pacific Ring of Fire / far from the Pacific Ring of Fire

c. Near coastal areas / inland areas

d. The western coastline of North and South America / the eastern coastline of

North and South America

e. Southern Africa / south and eastern Asia

9. There are three main types of plate margin (destructive, constructive and conservative). For each plate margin type:

a. Draw a diagram showing how the plates move (Towards each other? Apart? Alongside each other?)

b. Write a sentence describing what happens c. Indicate whether earthquakes and/or volcanic eruptions occur as a result d. Give an example (use the map above to help you) e.g. ‘where the South

American and Nazca plates meet’

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Destructive plate margin

a. The plates move together / apart / alongside each other

b. At a destructive plate margin,

________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________.

c. Earthquakes occur here / volcanoes occur here / earthquakes and volcanoes occur here

d. Example: ___________________________________________

Constructive plate margin

a. The plates move together / apart / alongside each other

b. At a constructive plate margin,

_______________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________.

c. Earthquakes occur here / volcanoes occur here / earthquakes and volcanoes occur here

d. Example: ___________________________________________

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Conservative plate margin

a. The plates move together / apart / alongside each other

b. At a conservative plate margin,

_______________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________.

c. Earthquakes occur here / volcanoes occur here / earthquakes and volcanoes occur here

d. Example: ___________________________________________

Key idea: The effects of, and responses to, a tectonic hazard vary between areas of contrasting levels of wealth.

10. Below some effects of and responses to tectonic hazards are listed. Code each one as

either PE (primary effect), SE (secondary effect), IR (immediate response) or LR (long-

term response).

buildings collapse

water pipes burst

disease spreads

evacuation

communication links destroyed

building regulations improved

volunteers arrive to search for survivors

fires spread due to gas pipes bursting

people are injured or killed

income is lost

investment in the area is focussed on

rebuilding

search and rescue teams deployed

evacuation services

medical tents set up

money is donated to purchase medicines

and other supplies

homes are rebuilt at huge expense

trade is made more difficult

economic growth slows

people moved permanently from the area

homelessness

people die of cold and exposure

landslides

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new jobs in the construction industry

tents given out by charities

schools and hospitals rebuilt

people live in refugee camps

shops and businesses ruined

gas pipes burst

rioting

farmland, crops and livestock destroyed

water sources contaminated

the government has to borrow money for

reconstruction

sites of religious and cultural importance

are lost

water is contaminat

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The effects of tectonic hazards are often worse in places that have low

incomes. Select one effect from the list above, and create a flow chart in the

space below to show why the effects may be more devastating in a LIC than a

HIC.

11. To help you do this, complete the table below. Try to include place-

specific details (e.g. place names) and facts and figures (e.g. number of

destroyed houses and lives lost).

HIC named example Earthquake or volcano? _______________________ Place? ____________________________________ Year? ________________________

LIC named example Earthquake or volcano? _______________________ Place? ____________________________________ Year? ________________________

Primary effects

Secondary effects

Immediate responses

Named examples alert! The specification says that you need to ‘Use named examples to show how

the effects and responses to a tectonic hazard vary between two areas of

contrasting levels of wealth.’

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Long-term responses

Tip: you need to be able to assess which effects were most/least severe and

which responses were most/least effective. Develop a coding system in the

space below and label the information in your table above.