Natural Hazards

Question 1

What is the inner core made of?

Answer 1

Iron and nickel

Question 2

What is an example of a destructive plate boundary?

Answer 2

South America: Mazda plate is subducting under the South American plate to form the Peru Chile trench and the Andes

Question 3

What is an example of a constructive plate boundary?

Answer 3

The mid Atlantic ridge: the Eurasian plate and the North American plate are moving apart

Question 4

What is an example of a conservative plate boundary?

Answer 4

The Pacific plate is moving faster but in the same direction as the North American plate on the west coast of the USA (i.e. the San Andreas fault)

Question 5

What is an example of a collisional plate boundary?

Answer 5

The Indian plate and the Eurasian plate are colliding to form the Himalayas

Question 6

What is the Richter scale?

Answer 6

A measurement for the amount of energy released by an earthquake. It doesn’t have an upper limit and it is logarithmic (a 5 is 10x more powerful than a 4)

Question 7

What is a hotspot?

Answer 7

An area where the mantle is really hot so volcanoes form even though it may not be a plate boundary (i.e. Hawaii)

Question 8

What are the primary impacts of earthquakes? List 6

Answer 8

Collapsing buildings and bridges
People injured or killed by debris
Infrastructure damaged - roads, railways, ports and airports
Electricity cables damaged
Telephone poles destroyed
Underground sewage systems damaged

Question 9

What are the secondary impacts of earthquakes? List 8

Answer 9

Landslides
Tsunamis
Leaking gas ignited - fires
People left homeless
Physiological problems
Lack of sanitation and limited water supply - diseases spread
Difficult to get emergency vehicles through
Businesses damaged - unemployment - negative multiplier effect

Question 10

Why are the impacts of earthquakes more severe in LEDCs? Explain 4

Answer 10

Poor quality housing is destroyed more easily
Poorer infrastructure makes it harder to distribute aid
They don’t have much money to protect themselves or to react quickly
Healthcare is often worse so people die from treatable injuries if there aren’t enough supplies

Question 11

Why do people live in places where earthquakes happen?

Answer 11

They have friends and family there
They are employed in the area
They are confident of government support
People don’t think severe earthquakes will happen again

Question 12

How can you reduce the impacts of earthquakes? Explain 5

Answer 12

Prediction - use previous data, detect tremors
Building techniques - reinforced concrete, energy absorbing foundations
Planning - fire breaks, training emergency services, plan evacuation routes, avoid building on prone areas
Education - how to evacuate, how to make a survival kit
Aid - from governments or organisations

Question 13

Why do people choose to live near volcanoes? List 3

Answer 13

Fertile soil from minerals from ash and lava
Tourist attraction - boosts local economy, jobs available
Source of geothermal energy

Question 14

What are the primary impacts of volcanic eruptions? List 5

Answer 14

Buildings and roads are destroyed by lava and pyroclastic flow
People are killed by falling rocks and pyroclastic flows
Crops are damaged
Water supplies are contaminated
People, animals and plants are suffocated by gases

Question 15

What are the secondary impacts of volcanoes? List 8

Answer 15

Lahars - flooding, more deaths, injuries
Fires
Psychological impacts
People left homeless
Shortage of food from damaged crops
Roads blocked so aid is hard to distribute
Businesses are damaged leading to unemployment
Sulphur dioxide released causes acid rain

Question 16

How can the impacts of volcanic eruptions be reduced? Explain 5

Answer 16

Prediction: small earthquakes, released gas, changes in shape - GPS monitoring
Planning: firebreaks, trained emergency services evacuate routes, hazard mapping
Building techniques: strengthen so they don’t collapse under ash, lava diverted using barriers
Education: survival kit, what to do if there is an eruption
Aid

Question 17

What areas of the world are most at risk from drought? List 5

Answer 17

North Eastern Africa
the Sahel
Southern Africa
the Middle East
Australia

Question 18

What are the climatic conditions that cause droughts?

Answer 18

Changes in atmospheric circulation - makes annual rains fail

High pressure weather systems can block depressions

Question 19

What are the primary impacts of droughts? List 4

Answer 19

Vegetation dies
People and animals die of dehydration
Aquatic animals because rivers/lakes dry up
Soil dries out and is eroded by wind and rain

Question 20

What are the secondary impacts of droughts? List 7

Answer 20

Animals/humans die from starvation
Soil erosion increases which can lead to desertification
Conflicts over supplies
Migration
Wildfires
Dust storms
Loss of jobs (I.e. at farms)

Question 21

What are the human activities that make drought worse? Explain 2

Answer 21

Over grazing - reduces vegetation, causes erosion

Excessive irrigation - depletes rivers and lakes so there’s less water and causes salinisation

Question 22

How can you reduce the impacts of droughts? Explain 5

Answer 22

Prediction - monitoring rainfall, measuring soil moisture so you can prepare (ration water, move people)
Farming techniques - growing drought resistant crops (millet, olives), irrigating more effectively (drip irrigation)
Water conservation - in homes, using water butts
Increase water supplies - wells, reservoirs
Aid - emergency aid, aid to fund development projects

Question 23

Which techniques used to reduce drought impacts may not be sustainable? Explain 3

Answer 23

Wells can deplete water supplies
Reservoirs can reduce water downstream
Emergency aid is expensive and isn’t a long term solution

Question 24

When and where do hurricanes form?

Answer 24

In the east pacific from June to October

In the Atlantic from August to October

Question 25

When and where do cyclones form?

Answer 25

In the Indian Ocean (North from October to November, south from December to March)

Question 26

When and where do typhoons happen?

Answer 26

The eastern Pacific - May to December and willy willies (south) from January to March

Question 27

What conditions are needed for a tropical storm to form? 2

Answer 27

Sea water 26.5°C or higher
Between 5° and 30° north or south of the equator - too near equator then coriolis effect is too weak, too far and it’s too cold

Question 28

What are the characteristics of tropical storms? 5

Answer 28

In the northern hemisphere they spin anti-clockwise and move northwest
They are hundreds of kilometres wide
Usually last between 7 and 14 days
The eye can be 50km across and inside it is low pressure
Travel at around 15kmh but wind speeds can reach 120kmh

Question 29

How are tropical storms formed?

Answer 29

Ocean temperatures warm to 26.5°C
Water evaporates and warm air rises and condenses to form clouds creating low pressure near the water
Since warm air moves to lower pressure (cold air) the air keeps flowing up to create clouds and rain
Air is ejected at the top and it goes round the sides and down to form the eye

Question 30

What are the primary impacts of tropical storms? 9

Answer 30

Buildings and bridges are destroyed
Rivers and coastal areas flood
People drown, get injured or are killed by debris
Roads, railways, ports and airports are damaged
Electricity cables and telephone poles and cables are destroyed
Sewage overflows and can contaminate water supplies
Crops and livestock are damaged
Heavy rain makes hills unstable causing landslides
Beaches are eroded and coastal habitats are damaged

Question 31

What are the secondary impacts of tropical storms? 6

Answer 31

People are homeless
Shortage of clean water
Roads and blocked so emergency aid is hard to distribute 
Businesses are damaged - unemployment
Shortage of food
Physiological impacts

Question 32

Why are the impacts of tropical storms more severe in LEDCs? 6

Answer 32

Poor quality housing is more easily destroyed
Poorer infrastructure make aid hard to distribute (more deaths)
More people depend on farming so more people lose livelihoods
Don’t have much money to prepare (flood defences)
Don’t have the resources (food, helicopters) to react straight away
Healthcare is less developed, hospitals have less supplies so people die from treatable injuries

Question 33

What are the ways of reducing the impacts of tropical storms? 5

Answer 33

Prediction - radar, satellite and air craft data, computer models -> evacuation, boarding up windows
Planning - future developments planned to avoid prone areas, train emergency services, plan evacuation routes
Building techniques - reinforced concrete, secured roofs, flood defences
Education - how to prepare and evacuate, survival kit
Aid - from governments or organisations

Question 34

What is high pressure?

Answer 34

Cool, descending air which spirals out at low levels. Will flow towards areas of low pressure.

Question 35

What is low pressure?

Answer 35

Warm, rising air which draws more air in and spirals upwards at low levels

Question 36

How can El Niño cause drought?

Answer 36

It reverses the wind pattern in the inter tropical convergent zone so places no longer get winds bringing moisture so drought is experienced

Question 37

What can the primary impact of the ground being to hard lead to?

Answer 37

It’s hard for plants to grow and establish root systems which can cause lack of food so animals die and there is a famine. Also leads to desertification because the once-fertile topsoil gets blown away (soil erosion)

Question 38

What are the 8 steps that lead to hurricane formation?

Answer 38

1) water temperature = 26.5°C
2) the warm water reaches a depth of 60m
3) this causes rapid evaporation - cumulonimbus clouds
4) warm, moist air rises & meets cool, dry air above and condenses
5) Coriolis effect causes the clouds to spin
6) trade winds are sucked in
7) wind speed = 74mph
8) cool, dry air descends to form the eye of the storm