Paper 1: The challenge of natural hazards Flashcards
(150 cards)
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.