Natural Hazards Flashcards
1
Q
What is a natural hazard?
A
- A natural process which could cause death, injury or disruption to humans, or destroy property and possessions.
2
Q
What is a natural disaster?
A
- A natural hazard that has actually happened.
3
Q
What are geological hazards? What are some examples?
A
- Geological hazards are caused by land and tectonic processes.
- They include volcanoes, earthquakes, landslides and avalanches.
4
Q
What are meteorological hazards? What are some examples?
A
- Caused by weather and climate.
- Tropical storms, heatwaves, cold spells
5
Q
What is hazard risk?
A
- The probability of people being affected by a hazard in a particular area.
6
Q
How can vulnerability affect hazard risk?
A
- The more people that are in area exposed to natural hazards, the greater the probability they will be affected by a natural hazard.
7
Q
How can capacity to cope affect flood risk?
A
- The better a population can cope with an extreme event, the lower the risk of them being severely affected.
8
Q
How can the type of natural hazard affect flood risk?
A
- The risk from some hazards is greater than others.
9
Q
How does frequency affect hazard risk?
A
- Natural hazards that occur more often may carry a higher risk.
10
Q
How does magnitude affect hazard risk?
A
- More severe natural hazards have the greatest effects.
11
Q
What are primary effects?
A
- Immediate impacts caused by the hazard itself.
12
Q
Examples of some generic primary effects:
A
- Buildings and roads destroyed
- People injured or killed e.g when buildings collapse
- Crops and water supplies can be damaged or contaminated
- Electricity cables, gas pipes and communication networks can be damaged, cutting off supplies.
13
Q
Examples of some (generic) secondary effects:
A
- Hazards can trigger other hazards
- Aid and emergency vehicles cannot get through because or blocked roads/bridges which can cause more deaths.
- Shortage of clean water, lack of proper sanitation makes it easier for disease to spread.
- Food shortages can occur if crops are damaged, livestock are killed or supply lines are blocked.
- Economy can be weakened - damage to businesses can cause unemployment, and the reconstruction process can be very expensive.
14
Q
Examples of some generic immediate responses:
A
- Evacuate people (before the hazard)
- Treat the injured and rescue people
- Recover dead bodies to prevent the spread of disease
- Provide temporary supplies of electricity or gas
- Provide food, drink and shelter
- Aid workers, supplies, financial donations
15
Q
Examples of some generic long term responses:
A
- Repair homes or rehouse people
- Repair or rebuild buildings, roads, railways and bridges
- Reconnect broken electricity, water, gas and communications connections
- Improve forecasting, monitoring and evacuation plans
- Improve building regulations
- Boost economic recovery e.g by promoting tourism.
16
Q
What is continental crust?
A
- Thicker (30-50 km)
- Less dense
17
Q
What is oceanic crust?
A
- Thinner (5-10 km)
- Denser
18
Q
Why do tectonic plates move?
A
- Because of convection currents in the mantle.
19
Q
What are plate margins/boundaries?
A
- The places where plates meet.
20
Q
Destructive Margins involving oceanic and continental:
A
- Where two plates move towards each other.
- Where an oceanic plate meets a continental plate, the denser oceanic plate is subducted and destroyed, creating gas-rich magma.
- Violent volcanoes, violent earthquakes and ocean trenches occur here.
- Example: West Coast of South America, the oceanic Nazca plate is being subducted beneath the continental South American palate, creating the Atacama Trench.
- Example: Andes Mountain Range
21
Q
Destructive Margins involving two continental plates:
A
- Where two plates move towards each other.
- The ground is folded upwards, creating fold mountains.
- Violent earthquakes
- Himalayas
22
Q
Constructive Margins:
A
- Where two plates move away from each other.
- Magma rises from the mantle to fill the gap and cools, creating new crust.
- Gentle earthquakes and gentle volcanoes
- Iceland is an example of this (the movement of the Eurasian plate and the North American plate away from each other).
23
Q
Conservative Margins:
A
- Where two plates are moving sideways past each other, or are moving in the same direction but at different speeds.
- Crust isn’t created or destroyed.
- San Andreas Fault, California.
- Violent Earthquakes
24
Q
What is the focus?
A
- The point in the Earth where the Earthquake starts.
25
What is the epicentre?
- The point on Earth’s surface, straight above the focus.
