The Challenge Of Natural Hazards Flashcards
What is a natural hazard?
A natural process which could cause death, injury, disruption to humans or destroy property.
What is a natural disaster?
A natural hazard that actually happened
What are the two main types of natural hazard?
Geological hazard and meteorological hazard
What are geological hazards caused by?
Land and tectonic processes.
What are meteorological hazards caused by?
Weather and climate.
Give examples of geological hazards
Volcanoes, earthquakes, landslides and avalanches.
Give examples of meteorological hazards.
Tropical storms, heat waves, cold spells and climate change
What is a hazard risk?
The probability that a natural hazard occurs.
What are the different factors that affect the hazard risk from natural hazards?
Vulnerability, capacity to cope and nature of natural hazards
Explain how vulnerability affects the hazard risk.
More people in areas exposed to natural hazards, greater the probability they will be affected by the hazard. Hazard risk is higher.
Explain how capacity to cope affects the hazard risk.
Natural hazards have to affect human activities to count as hazard. Better a population can cope with the extreme event, lower the threat. HICs usually cope better.
Explain how nature of natural hazards affects the hazard risk.
Type - some hazard risks are greater than others. Frequency - some occur more often than others, increasing hazard risk. Magnitude - more severe hazards, cause greater effects than less severe hazards
What is the core of the earth made of?
Iron and nickel
What is mantle?
Semi molten rock that moves very slowly.
What is crust?
The outer layer of earth.
What are tectonic plates?
Divided slabs of crust that float on the mantle
What are the two types of crust?
Continental crust and oceanic crust
What are the differences between continental crust and oceanic crust?
Continental crust - thicker (30 - 50 km) and less dense. Oceanic crust - thinner (5-10 km) and more dense.
Why are the plates moving?
Because of convection currents in the mantle underneath the crust
What are plate margins?
The places where plates meet
What are the three types of plate margins?
Destructive margins, constructive margins and conservative margins.
Describe destructive margins
Two plates are moving towards each other.
What happens when an oceanic plate meets a continental plate at a destructive margin?
The denser oceanic plate is forced down into the mantle and destroyed
What happens when two continental plates meet at a destructive margin?
The plates collide, the ground is folded and forced upwards, to create mountain ranges.
Describe constructive margins.
Two plates are moving away from each other.
What happens when two plates move away from each other?
Magma rises from the mantle to fill the gaps and cools, creating new crust.
Describe conservative margins.
Two plates moving sideways past each other but at different speeds. Crust isn’t created or destroyed.
