Hazards Flashcards
What is a hazard?
A threat of an event that will have a negative effect on people, environment and properties.
There are two types of hazards:
Physical - caused by natural environment
Human - caused by humans
Why do tectonic plates move?
Tectonic plates move because they are floating on top of the liquid mantle. The mantle itself moves due to convection currents: hot rock rises, gives off some heat, then falls. This creates vast swirls of moving liquid rock under the crust of the earth, which jostles the plates of crust on top.
What are Collision Plate Boundaries?
Collision Plate Boundary- Collision zones
Collision zones form when two continental plates collide. Neither plate is forced under the other, and so both are forced up and form fold mountains.
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What are Constructive Plate Boundaries?
A constructive plate boundary, sometimes called a divergent plate margin, occurs when plates move apart. Volcanoes are formed as magma wells up to fill the gap, and eventually new crust is formed.
What are Conservative Plate Boundaries?
Conservative Plate Boundary- A conservative plate boundary, sometimes called a transform plate margin, occurs where plates slide past each other in opposite directions, or in the same direction but at different speeds.
What are Destructive Plate Boundaries?
Destructive Plate Boundary- A destructive plate boundary is sometimes called a convergent or tensional plate margin. This occurs when oceanic and continental plates move together. The oceanic plate is forced under the lighter continental plate. Friction causes melting of the oceanic plate and may trigger earthquakes. Magma rises up through cracks and erupts onto the surface.
What are the 4 different types of plate boundaries?
Conservative, Constructive, Collision and Destructive
What is a tropical storm?
A tropical storm is a hazard that brings heavy rainfall, strong winds and other related hazards such as mudslides and floods.
Different names given to tropical storms are:
Hurricane - Atlantic Ocean
Cyclones - Indian Ocean
Typhoons - Pacific Ocean
How do tropical storms form?
The warm oceans heats the air above.
Rising warm air evaporates and starts to spin.
The air then cools and condenses to form a towering cumulonimbus cloud.
Intense low pressure sucks in air, causing very strong winds.
What were the effects of the Katrina Hurricane?
- New Orleans was one of the worst affected areas because it is below sea level and protected by levees. -The defences were unable to cope with the strength of Katrina.
- Despite an evacuation order, many of the poorest people remained in the city.
- People sought refuge in the Superdome stadium. -Conditions were unhygienic, and there was a shortage of food and water. Looting was commonplace throughout the city. Tension was high and many felt vulnerable and unsafe.
- 1 million people were made homeless and about 1,200 people drowned in the floods.
- Oil facilities were damaged and as a result petrol prices rose in the UK and USA.
What were the responses of the Katrina Hurricane?
- Although many people were evacuated, it was a slow process and the poorest and most vulnerable were left behind.
- $50 billion in aid was given by the government.
- The UK government sent food aid during the early stages of the recovery process.
- The National Guard was mobilised to restore and maintain law and order in what became a hostile and unsafe living environment.
What is a tornado?
A tornado is a violent rotating column of air.
How do tornadoes form?
The initial funnel which hovers over the surface grows from a thunderstorm. If conditions are favourable a tornado takes shape and reaches the Earth. When, the conditions start to change, the funnel narrows and starts to rise gradually toward the cloud.
What is a tornado alley?
Tornado Alley is the Area in the united states of America where large numbers of Tornado’s usually take place.
