Natural Hazards Flashcards
6 natural hazards (geological - rocks)
- Volcanic Eruption
- Sink hole
- Land slide
- Earthquake
- Tsunami
- Avalanche
7 natural hazards (atmospheric - sky)
- Blizzard
- Drought/Heatwave
- Wild Fire
- Hail Storm
- Extreme Storms
- Flash Flood
- Hurricane/Typhoon/Cyclone
1 natural hazard (hydrological - water)
- Whirlpool
6 Factors affecting the severity of the impact (of the natural hazard)
- Position in comparison to the equator
- Education
- Emergency Services - Recovery
- Warning System
- Population Density
- Infrastructure
The crust is…
The crust is the outermost layer of the Earth, its split into sections called tectonic plates. The tectonic plates float on a liquid mantle.
The most likely plate tectonics theory is…because…
Theory 1. Over billions of years the Earth has grown in mass then shrunk several times, as it has grown the continents are broken apart then shifted as it shrinks.
Theory 2. The land hasn’t moved, the ocean has flooded areas and volcanoes have created new rocks.
Theory 3. The tectonic plates fit together like jigsaw pieces. These plates are always moving but only about 2 cm a year.
The most likely plate tectonics theory is Theory 3 because it also explains why we have volcanoes and mountains and it is the most scientifically realistic.
What is a conservative plate margin?
Where two tectonic plates slide past each other and can create earthquakes.
What is a constructive plate margin?
Where two tectonic plates pull away from each other and magma rises to fill the gap adding new rock to the surface.
What is a destructive plate margin?
Where a continental plate is pushing against an oceanic plate. The oceanic plate is subducted (goes underneath) as it is denser. This creates an ocean trench and a volcano.
How does a volcano form?
A volcano is formed at a destructive plate boundary. Two plates push on each other and the denser oceanic plate gets subducted. In the suduction zone the plate melts into magma. The friction and pressure caused by a build up of magma causes the volcano to erupt.
What is a convection current?
The core heats the magma, as it gets hot it rises. Then it begins to cool and sinks. It creates a circular motion called a convection current.
What is a composite volcano?
1 reason why these are dangerous
A composite volcano occurs at a destructive plate margin. Repeated eruptions build up the successive layers. These have a narrow base and are very tall.
Lava may cool inside the vent which means the next eruptions is very explosive.
What is a shield volcano?
A shield volcano occurs at a constructive plate margin. These have frequent, non-violent eruptions,that have basic (runny) lava. They have a wide base, gentle slopes and are not very tall.
What are the two other names for Hurricanes?
Typhoons and Cyclones. (they are the same thing but in different parts of the world)
Where are Cyclones found?
Australia, Madagascar and places of the South East coast of Africa.
