The challenge of natural hazards Flashcards
All information is complied from Oxford Geography GCSE 9-1 AQA Revision guides. If you notice any issues please contact me at missgeorgiapark@gmail.com (24 cards)
What are natural hazards?
Sudden, severe events which make the natural environment difficult to manage.
What are the three categories for natural hazards?
Atmospheric
Geological
Flooding
Name a natural disaster for each category.
Atmospheric - droughts, tornadoes, lightning, heatwaves, blizzards, wildfires, snow storms, ash cloud, mudflows
Geological - earthquakes, volcanic eruptions, landslides, sink holes, avalanches, tsunamis, mudflows, ash clouds
Flooding - glacial bursts, storm surges, avalanches, tsunamis, mudflows, snow storms
*These are only possible answers there is more!
What is ‘hazard risk’?
The chance of being affected by a natural hazard.
What factors affect risk?
(Learn 4)
Urbanisation / Population density
Poverty
Wealth
Geographical location
Farming
Climate change
Describe the distribution of Earthquakes and Volcanoes.
Most of the Earth’s volcanoes and earthquakes occur around the edge of the Pacific Ocean and form the Pacific Ring of Fire. Earthquakes occur along conservative, constructive and destructive plate margins. Volcanoes occur along constructive and destructive plate margins.
Name the four layers of the Earth.
Crust
Mantle
Outer Core
Inner Core
Describe the theory of tectonic plates.
The Earth’s crust is broken into tectonic plates. It was once believed that
convection currents
in the mantle caused the plates to move. However, it is now recognised to be more complicated than this. Mechanisms called slab pull and ridge push are believed to move the tectonic plates. Ridge push is where the new crust formed at divergent
plate margins
is less dense than the surrounding crust and so it rises to form oceanic ridges. The older seafloor either side of the ridge slides away and this moves the seafloor apart – moving the tectonic plates.
a) Describe or draw a destructive plate margin and name the hazards.
b) Name an example.
Process:
- An oceanic plate moves towards the continental plate.
- The denser oceanic plate is subducted beneath the Continental plate.
- Friction between the plates as they move causes earthquakes.
- The oceanic plate melts in the mantle and mixes with sea water. This liquid rises up through cracks in the mantle as a volcanic eruption.
Hazards: powerful earthquakes and violent composite volcanoes.
Example: Nazca and South American plates
*If you have drawn the destructive plate boundary follow this link to check your drawing: https://www.internetgeography.net/wp-content/uploads/h5p/content/581/images/image-6592beb4df80a.jpg
a) Describe or draw a conservative plate margin and name the hazards.
b) Name an example.
Process:
- Two plates slide past each other.
- As they move, they are jagged so get caught on each other.
- Pressure builds up and is released as an earthquake when the plates suddenly jolt free.
Hazards: earthquakes
Example: San Andreas Fault
*If you have drawn the conservative plate boundary follow this link to check your drawing: https://www.internetgeography.net/wp-content/uploads/2018/02/Conservative-margin.png
a) Describe or draw a constructive plate margin and name the hazards.
b) Name an example.
Process:
- Two plates move apart from each other.
- This creates a gap in the Earth’s crust.
- Magma from the mantle rises to fill this gap and a volcanic eruption occurs.
- Small earthquakes also happen due to the movement of the magma.
Hazards: gentle earthquakes and gently sloping shield volcanoes.
Example: Mid Atlantic Ridge (Iceland)
*If you have drawn the constructive plate boundary follow this link to check your drawing: https://www.internetgeography.net/wp-content/uploads/h5p/content/600/images/image-659dacbe37b31.jpg
Definition Check In:
Conservative Margin
Constructive Margin
Destructive Margin
Distribution
Natural Hazard
Plate Margin
Tectonic Hazard
Conservative Margin - Two plates sliding alongside each other, in the same or different directions.
Constructive Margin - Tectonic plate margin where rising magma adds new material to plates that are moving apart.
Destructive Margin - Two plates converging and oceanic plate is subducted.
Distribution - The way something is spread out or or arranged over a specific area.
Natural Hazard - Extreme natural events that can cause loss of life.
Plate Margin - The border between two tectonic plates.
Tectonic Hazard - Natural hazard caused by the movement of tectonic plates.
Exam Questions:
a) Other than tectonic hazards, give two examples of natural hazards [2 marks]
b) Explain why earthquakes take place at conservative plate margins [4 marks]
- I highly recommend getting your exam questions marked by a geography teacher but if you can’t feel free to email me your answer at missgeorgiapark@gmail.com
Mark scheme:
a) Tropical storms, heatwaves
EXCEPT SUITABLE ALTERNATE ANSWERS.
b) This is a level marked question please ask a teacher or email me.
Case Study: Tectonic events in two contrasting countries.
Chile and Nepal
CHILE
a) can you name how high the earthquake was on the Richter Scale?
b) Can you name where the earthquake was?
c) Can you name the causes of the earthquake?
d) Can you name 2 primary effects and 1 secondary effect?
e) Can you name two immediate responses and two long term responses?
f) Can you name the year the earthquake happened and what type of country Chile is (e.g. HIC, NEE or LIC).
a) 8.8.
b) off coast of central Chile.
c) Earthquake at sea.
destructive plate margin.
d) Primary: 500 killed.
4500 schools destroyed.
Secondary: 1500km of roads damaged mainly by landslides.
e) Immediate: power and water restored to 90% of homes within 10 days.
emergency services acted swiftly.
International help and field hospital.
Long - term: month after government launched housing reconstruction helping nearly 200,000 households.
Chile’s strong economy, based on copper exports, could be rebuilt without much foreign aid.
f) 2010 HIC
Case Study: Tectonic events in two contrasting countries.
Chile and Nepal
NEPAL
a) can you name how high the earthquake was on the Richter Scale?
b) Can you name the causes of the earthquake?
c) Can you name 2 primary effects and 1 secondary effect?
d) Can you name two immediate responses and two long term responses?
e) Can you name the year the earthquake happened and what type of country Nepal is (e.g. HIC, NEE or LIC).
a) 7.9.
b) Destructive plate margin
c) Primary: 9000 killed.
3 million left homeless.
Secondary: ground shaking triggered landslides and avalanches.
d) Immediate: helicopters rescued many people caught in avalanches on Mount Everest and delivered supplies.
Search and rescue teams, water and medical support from the UK, China and India
Long - term: Over 7000 schools to be rebuilt or repaired with stricter building codes.
Tourism, a major source of income, to be boosted - some heritage sites reopened.
e) 2015 LIC
Why do people live in areas near tectonic hazards? Can you name 4.
- Poor people have no choice - money, food and family are seen as more important = uneducated = don’t know / understand the risks.
- Earthquakes and volcanic eruptions are rare, so not seen as a great threat.
- Volcanoes can bring benefits such as fertile soil, rich mineral deposits and hot water.
- Plate margins often coincide with favorable areas for settlement and trade.
Can you name the PPPM method for volcanoes and earthquakes?
Prediction
Protection
Planning
Monitoring
Can you describe the prediction and monitoring methods?
We cannot predict earthquakes but we can use historical records to determine when an earthquake is likely to happen.
Satellites can monitor changes in the shape of volcanoes and aircraft’s can monitor ash and gas release prior to eruptions.
Can you describe protection methods?
Aseismic buildings and shutters on windows. Shock absorbers under the building.
Earth walls for Lava and the lava can be diverted away.
Can you describe planning methods?
Plan an evacuation route. Create emergency kits. Practice earthquake drills. Emergency services can train for earthquakes and volcanic eruptions.
Exam Questions:
a) For two tectonic hazards you have studied, compare the primary effects of these hazards [4 marks]
b) Suggest why people continue to live near volcanic hazards [4 marks]
c) Evaluate the effectiveness of methods to reduce the risks from earthquake hazards [9 marks +3 SPaG]
All these questions are level marked.
Ask your teacher or email me at missgeorgiapark@gmail.com
Name the types of cells in global atmospheric circulation.
Polar Cell
Ferrel Cell
Hadley Cell
a) Why do places get hot and wet weather?
b) Why do places get hot and dry?
c) Why do places get mild and wet weather?
d) Why do places get cold and dry weather?
a) Concentrated solar isolation creates a hot climate. Hot air rises, creating low pressure. It cools and condenses to give predictable convectional rainfall.
b) Sinking air loses moisture, giving clear blue skies, and little precipitation. It is hot because it is still quite close to the equator.
c) Air moving north in the Ferrel cell is forced up when it meets cold air from the Polar cell. It cools and condenses, giving frontal rainfall.
d) The Sun’s isolation is spread out over a large area, making it cold. Sinking air in the Polar cell gives high pressure and dry weather.
Exam Question:
Explain why Antarctica is a desert [2 marks]
Because it receives very little precipitation. This is because it is situated where air from the Polar cell is sinking, giving high atmospheric pressure. As air sinks, it warms and its ability to hold water increases, meaning that precipitation is less likely.
