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