Paper 1: The challenge of natural hazards Flashcards
What is a natural hazard?
A natural event that threatens people or has the potential to cause damage, injury and death.
Give examples of geological (tectonic) hazards
Earthquakes, volcanoes and tsunamis
Give examples of meteorological (weather) hazards
Tropical storm, heavy rain, blizzard, heatwave
Give one reason why the incidence of meteorological hazards is increasing
Climate change
What factors affect hazard risk?
Population density, whether the country can afford to cope, the nature, magnitude and frequency of the hazard
How can population density affect hazard risk?
More people in the area = more people to get injured/killed
Give 2 reasons why a high income country is likely to cope better with natural hazards
- More money = higher quality buildings which are less likely to be damaged in an earthquake; 2. More money = better short and long term responses such as rescuing people and rebuilding.
What are the four layers of the Earth?
Inner core, outer core, mantle and crust
What is the outer layer of the Earth?
Crust
What are the properties of the mantle?
Thick sticky liquid made up of molten rock
What is the crust divided in to?
Tectonic plates
What causes tectonic plates to move?
Convection currents in the mantle
Which is more dense out of continental or oceanic plates?
Oceanic
What are the places where the plates meet known as?
Plate margins/plate boundaries
What are the three types of plate margin?
Constructive, destructive and conservative
What is the margin called when plates are converging (moving towards each other?
Destructive
What is the margin called when plates are diverging (moving away from each other)?
Constructive
What is the margin called when the plates are sliding past each other or moving in the same direction at different speeds?
Conservative
When a continental plate meets an oceanic plate at a destructive margin, which is forced underneath the other?
Oceanic plate is forced underneath as it is denser
How do volcanoes occur at destructive plate boundaries?
Oceanic plate is forced beneath continental plate where it melts. Magma builds up. Pressure increases and can release explosively as a volcanic eruption.
How do earthquakes occur at destructive plate boundaries?
As the oceanic plate is sub ducted (forced underneath) it can get stuck due to friction. Pressure builds up. When the pressure is released, shockwaves are emitted causing an earthquake.
How do earthquakes occur at conservative plate margins?
As plates slide past each other, the jagged edges can get stuck due to friction. Pressure builds up. When the pressure is released it causes shockwaves leading to an earthquake.
How do earthquakes occur at constructive plate margins?
Pressure builds up along cracks in the plates as they move away from each other. When the pressure is released it causes shockwaves which cause an earthquake.
How do volcanos occur at constructive plate margins?
As the plates move apart, molten rock rises from the mantle to fill the gap and cools, creating new crust.
What plate margins are volcanoes found at?
Destructive and constructive
What plate margins do earthquakes occur at?
All three
What is magma called when it has erupted and is above the ground?
Lava
What is meant by the magnitude of an earthquake?
How strong it was
What does distributed mean?
How they are spread out.
How are earthquakes and volcanoes distributed?
They occur on plate boundaries
What is a primary effect?
The immediate impacts of the ground shaking
What is a secondary effect?
An impact of the earthquake that happens later on as a result of a primary effect.
What is an immediate response?
Dealing with the immediate aftermath of an earthquake e.g. rescuing people, providing clean drinking water etc.
What is a long term response?
Rebuilding and trying to get back to normal over the following weeks, months and years after an earthquake.
Give 4 reasons why people chose to live in tectonically active areas?
- They’ve always lived there and don’t want to move away from friends and family; 2. They don’t think it will happen to them; 3. Soil around volcanoes is very fertile so good for farming; 4. Volcanoes attract tourists so people living nearby can get work in the tourism industry.
What are the 4 management strategies for reducing the effects of tectonic hazards?
Monitoring, prediction, protection and planning
Monitoring: How can earthquakes be monitored?
Seismometers and lasers sense tiny movements in the ground and can sometimes give a small amount of warning before an earthquake.
Monitoring: How can volcanoes be monitored?
Scientists can check for changes in the state of a volcano such as escaping gas, tiny earthquakes and changes in the shape of the volcano that can suggest it is likely to erupt.
Prediction: Can earthquakes be predicted?
Predicting earthquakes is not reliable, but scientists can figure out which areas are more at risk.
Prediction: Can volcanic eruptions be predicted?
Yes
Prediction: How can predicting a volcanic eruption help?
It can give people time to evacuate, reducing the number of injuries and deaths.
Protection: How can we protect against earthquakes?
Earthquake-proof buildings, strengthening existing buildings and having automatic cut off switches on gas to prevent gas leaks after an earthquake.
Protection: How can we protect against volcanoes?
Strengthening buildings so they can withstand the weight of falling ash.
Planning: Give 3 ways in which planning can reduce damage from future earthquakes and volcanoes?
- Train emergency services on how to rescue people; 2. Educate people on what to do if an earthquake or volcano occurs; 3. Encourage people to have survival kits ready.
What is our case study of a tectonic hazard in an LIC?
Nepal
What year did the Nepal earthquake take place?
2015
What was magnitude was the Nepal earthquake on the Richter scale?
7.9
What type of plate margin did the earthquake occur on?
Destructive
Primary effects: How many schools were destroyed?
7000
Is loss of schools a social, economic or environmental impact?
Social
Primary effects: How many people died?
9000
Primary effects: What was the cost of recovering from the earthquake?
US $5 billion
Secondary effects: How many people were left homeless?
3 million
Secondary effects: What happened on Mount Everest?
Landslides and avalanches trapped people.
Immediate responses: What countries sent rescue teams to help rescue people?
UK, India and China
Immediate responses: How were people rescued from Mount Everest?
By helicopter
Immediate responses: How many people had to find temporary shelter?
300,000
Long term responses: How many schools had to be rebuilt?
7000
Long term responses: What did they do after the 2015 earthquake to try to reduce damage from future earthquakes?
Stricter building regulations so that the replacement buildings were stronger.
What is our case study of a tectonic hazard in an HIC?
Chile
What year did the Chile earthquake take place?
2010
What was magnitude was the Chile earthquake on the Richter scale?
8.8
What type of plate margin did the earthquake occur on?
Destructive
Primary effects: How many people died?
500
Primary effects: How many schools were destroyed?
4500
Primary effects: What was the cost of recovering from the earthquake?
US $ 30 billion
Secondary effects: What damaged 1500km of roads?
Landslides
What hit several coastal towns?
Tsunamis
Immediate responses: Why were temporary repairs made to Route 5 (a major road)?
So that aid vehicles could reach affected areas.
Immediate responses: How long did it take to restore power and water to 90% of homes?
10 days
Long term responses: A housing reconstruction plan was made to rebuild how many households?
200,000
What is global atmospheric circulation?
The movement of air around the world as it moves from areas of high pressure to areas of low pressure. It causes areas to have certain climates.
Which area of the Earth has receives most heat from the Sun?
The equator
What are the three cells of the global atmospheric circulation model?
Hadley, Ferrell and Polar
What is a tropical storm?
A spiralling weather system with heavy rain and high winds.
What are tropical storms also known as?
Hurricanes, cyclones and typhoons
What sea temperature do tropical storms need to form?
27°C +
Why so tropical storms spin?
Because of the rotation of the Earth
Which direction do tropical storms move?
West
How do tropical storms form?
High sea temperatures (27 degrees Celsius +) mean that water evaporates rapidly. The warm moist air rises, and cools. It condenses forming huge clouds. More air rushes inwards to fill the area of low pressure left by the rising air. The spinning of the Earth causes this air to spiral.
Why do tropical storms die when they move over land?
They are fuelled by warm moist air over the sea to fuel them. When them move over land, they quickly lose energy.
What is the hole in the middle of a tropical storm called?
The eye
What are the conditions like in the eye of the storm?
Calm - no wind or rain
What is the edge of the eye called?
The eye wall
What are the conditions like at the eye wall?
This is the most extreme part of the storm - very high winds and rainfall.
Where do tropical storms occur?
5° - 30° North and South of the equator
Do tropical storms occur on the equator?
No
How might climate change affect tropical storms?
Storms could be stronger and more places will be affected. They also could occur a longer period of the year.
Why might tropical storms occur in more places if the Earth’s climate warms?
More areas will have sea temperatures of 27°C+.
What is a storm surge?
When the high winds from a tropical storm force sea water onto the land, causing widespread flooding.
What are the 4 management strategies for reducing the effects of tropical storms?
Monitoring, prediction, protection and planning
How are tropical storms monitored?
Satellite images can be used to track the tropical storm.
Why is it useful to be able to predict tropical storms?
People in at risk areas can be evacuated. Loose objects can be tied down.
How can places plan for tropical storms?
Building new houses in areas that aren’t at risk of flooding. Making evacuation plans. Practicing rescuing people from flooded areas.
How can places be protected from tropical storms?
Flood defences such as sea walls. Strengthening buildings to withstand high wind.
What is our case study for tropical storms?
Typhoon Haiyan
When did Typhoon Haiyan occur?
2013
What strength was Typhoon Haiyan on the Safer-Simpson scale?
Category 5
Where did Typhoon Haiyan affect?
The Philippines
Primary effects: How many people died?
6300
Primary effects: How did most people die?
Drowned in the storm surge which was 15 metres high
Primary effects: How many people were displaced?
600,000
Primary effects: 90% of what city was destroyed?
Tacloban city
Primary effects: How many fishing boats were destroyed?
30,000
Secondary effects: How many people were left with no job?
6 million
Secondary effects: Shortage of water caused what secondary effect?
Spread of cholera
Immediate responses: How many evacuation centres were set up for people who had lost their homes?
1200
Immediate responses: What charity delivered food including rice?
Red cross
Long term responses: What were the ‘cash for work’ programmes?
People were paid to help clear debris and rebuild Tacloban.
Long term responses: Where were new homes built?
Away from areas at risk of flooding in the future.
What extreme weather hazards affect the UK?
Heavy rain, heatwaves and thunderstorms
Why is weather in the UK becoming more extreme?
Climate change
How do we know weather in the UK is becoming more extreme?
Temperature and rainfall records are regularly being beaten. Major flooding occurs more often.
What is our extreme weather in the UK case study?
Boscastle flood
When did the Boscastle flood occur?
2004
How much rain fell in 24 hours?
200mm
What was the name of the river that flooded?
River Valence
What physical (natural) factors contributed to the flooding?
High rainfall and steep valley sides
Social effects: What was the worst injury?
A man broke his thumb
Social effects: How many buildings were destroyed?
4
Economic effects: What museum was destroyed leading to a loss of tourism?
The Witchcraft museum
Environmental effects: What caused the sea to become polluted?
Fuel flowing out of damaged cars
Economic effects: How much did the damage cost?
£15 million
Management strategies: Why did they chop down trees near the river?
So if the river floods again in the future, the trees can’t fall and block the flow.
Management strategies: What was raised so that it would be above flood level?
The car park
Management strategies: What was done to the river channel?
It was widened to allow for a grater volume of water to pass through.
Define climate change
A change in the average atmospheric conditions over time
Is Earth’s climate currently getting warmer or colder?
Warmer
How has climate changed in the past?
Average temperature has fluctuated (gone up and down) in the past. This has caused ice ages when it has been cold and much warmer periods known as interglacial.
What evidence do we have for past climate change?
Tree rings, ice cores, temperature records and pollen analysis
How can tree rings tell us about past climate?
As a tree grows it forms a new ring every year. In warm wet years, trees grow faster. This means the thickness of each ring tells us what the climate was like that year.
How can ice cores tell us about past climate change?
Scientists drill into the ice to get a long core. Ice that has formed more recently will be at the top of the core, and older ice at the bottom. By analysing the gas in air bubbles in the ice they can tell what the temperature was like when if formed.
How can pollen tell us about past climate change?
Pollen from plants gets preserved in sediment (mud) at the bottom of lakes. Scientists can identify the type of pollen and date when the plant would have been alive. They can work out whether the plant would have been suited to warmer or cooler temperatures and therefore what the climate was like when the plant was alive.
Name 3 natural causes of climate change
Changes in the Earth’s orbit, volcanic activity and solar output
How do orbital changes affect climate change?
Over 100,000 years the shape the Earth goes around the sun changes from circular to oval and back again. When the orbit is circular, the Earth spends more time closer to the Sun so the climate is warmer. This is probably what caused past ice ages.
How can volcanic eruptions cause climate change?
Temporary cooling as ash blocks out the sun, followed by long term warming as volcanoes release greenhouse gases.
What is the greenhouse effect?
Heat from the Sun enters the Earth’s atmosphere and is reflected off the surface of the Earth. Some heat energy passes back out into space, but some gets trapped by greenhouse gases in the atmosphere. This is a natural process.
Give 2 examples of greenhouse gases
Methane and carbon dioxide (CO2)
What is the enhanced greenhouse effect?
Humans release more greenhouse gases into the atmosphere. This means that more heat from the Sun gets trapped so the Earth’s climate warms.
Name 3 human causes of climate change
Deforestation, agriculture and burning fossil fuels
How does deforestation cause climate change?
Trees absorb carbon dioxide which is a greenhouse gas. Less trees mean less is removed.
How does burning fossil fuels cause climate change?
Carbon dioxide is released when we burn fossil fuels.
Why do we burn fossil fuels?
To power transport, make electricity and power factories.
How does agriculture (farming) cause climate change?
Animals like cows release methane which is a greenhouse gas
How will climate change affect the environment?
Glaciers will melt, sea ice will melt , rising sea levels, habitats being destroyed, mass extinction of animals, more tropical storms, more extreme weather
How will climate change affect people?
Some places will be too hot to live in, sea level rise will flood coastal towns, farming will not be possible in some areas leading to malnutrition and more extreme weather will cause deaths.
What does mitigating climate change mean?
Trying to stop climate change from happening
What does adaptation to climate change mean?
Preparing for climate change to happen
Give 2 examples of mitigation strategies
Planting trees and international agreement
Give 2 examples of adaptation strategies
Building sea walls so coastal towns are less likely to be flooded by rising sea levels, and new farming techniques such as genetically modifying crops so that we will have enough food.
