natural Hazards

Question 1

what is a natural hazard?

Answer 1

a natural hazard is a natural process which has a social impact on people
if an extreme event did not have an impact on a person then it would not be considered a hazard.

Question 2

what are the two main types of hazards?

Answer 2

1. geological hazards
   they are hazards caused by the movement of tectonic plates and land
   e.g. volcanoes and earthquakes
2. meteorological hazards
   these are hazards caused by extreme weathers and climate
   e.g. tropical storms and heatwaves

Question 3

what is hazard risk?

Answer 3

hazard risk is the probability that a person is affected by a natural hazard

Question 4

what are the different factors that effect hazard risk?

Answer 4

1. vulnerability
   . the more people exposed to the hazard the greater probability they will be affected
   e.g. someone living near the coast have a higher hazard risk of flooding then those living in the city
2. management / capacity to cope
   . the better a place can cope with the hazard the lower the risk of them being highly effected
   e.g. HIC’s are better prepared for natural hazards then LIC’s as they can afford defences and evacuate people effectively
3. the type of natural hazard
   . the risk of some hazards are greater then others
   e.g tropical storms can be predicted whereas earthquakes are random with no warning giving to time for people to prepare

. frequency - natural hazards occuring more often have a higher risk

.magnitude - the higher the magnitude the more dangerous for people however if it is lower then it is less likely to hurt more people

Question 5

what are the two affects of natural hazards?

Answer 5

1. primary effects - immediate impacts
2. secondary effects - long term impacts

Question 6

describe the primary effects of natural hazards
(IMPACTS)

Answer 6

1. buildings and roads are destroyed by the natural hazard
   2.people injured and killed
   3.crops and water supplies damaged or contaminated
   4.electricity cables gas pipes and communication networks can be damaged cutting off supplies

Question 7

describe the secondary effects of natural hazards
(IMPACTS)

Answer 7

1. the first hazard can trigger other hazards e.g. earthquakes trigger tsunamis
2. aid and emergency vehicles cant get through due to blocked roads causing more deaths
3. a shortage of clean water and a lack of cleanliness makes it easier for disease to spread
4. food shortages can happen if crops are damaged livestock killed or supply lines blocked
5. countries economy weakens - damaged business causes unemployment and the reconstruction is expensive

Question 8

what are the immediate RESPONSES to a natural hazard?

Answer 8

1. evacuate people
2. treat injures and rescue anyone
3. recover the bodies to prevent diseases
4. provide supplies for electricity and gas
5. provide food and drink to people
6. foreign governments or charities may send aid workers supplies or financial donations

Question 9

what are the long term responses to natural hazards?

Answer 9

1. repair homes and rehouse people who have lost homes
   2.repair buildings roads railways and bridges
2. reconnect broken electricity water gas and communication connections
3. improve forecasting monitoring and evacuation plans
4. improve building regulations so that buildings can withstand similar hazards
5. Boost economic recovery e.g. promoting tourism etc

Question 10

what is the earths surface made out of?

Answer 10

the earths surface is made out of huge slabs of rock that are constantly moving in the crust.
this is known as
tectonic plates

Question 11

what are the layers of earth called?

Answer 11

the first layer - is called the crust , it is made up of solid rocks

the second layer - is known as the mantle, it is made up of semi molten rock known as magma

the third layer - is the outer core and it is made up of liquid iron and nickel

the forth layer - is called the inner core it is made up of solid iron and nickel

Question 12

what are the two types of tectonic plates?

Answer 12

1. continental plates
   - the crust is thicker and less dense
2. oceanic plates
   - the crust in thinner and more dense

Question 13

How/ why do the tectonic plates move?

Answer 13

tectonic plates move due to convection currents
- the earths core temperature, reaches around 6000 C which causes hot magma to rise up in the mantle
- the magma then eventually cools down and sinks back to the core
- this process is repeated and as the currents build up pressure it slowly carries the plates along

Question 14

what are the three types of plate margins?

Answer 14

1. destructive margins
2. constructive margins
3. conservative margins

Question 14

what is a destructive plate margin?

Answer 14

destructive plate margins are when:
- two plate are moving TOWARDS each other

• when an oceanic and continental plate’s move towards each other
• the denser oceanic plate subdues and is destroyed by the hot temperatures creating gas rich magma
• volcanoes and ocean trenches are then created
• where two continental plates meet neither is more denser then the other so both go up
• this creates mountains

Question 15

what is a constructive plate margin?

Answer 15

this is when two plate move AWAY from each other
- magma rises from the mantle to fill the gap creating new crust

Question 16

what is a conservative plate margin?

Answer 16

this is when two plates are moving in the same DIRECTION at different speeds
- CRUST IS NEITHER CREATED NOR DESTROYED

Question 17

at what plates are volcanoes commonly found?

Answer 17

volcanoes occur at:
constructive &
destructive plate margins

Question 18

how do volcanoes occur at a destructive plate boundary?

Answer 18

at destructive margins:
- the denser oceanic plate moves down the mantle where it melts
- a pool of magma forms which then rises through cracks in the crust called vents
- the magma (now called lava as it has come out of the volcano) erupts, forming a volcano

Question 19

how do volcanoes occur at constructive plate boundaries?

Answer 19

at constructive plate margins:
- the plates are moving away from each other hence their is a gap
- the magma rises up into the gap anf eventually forms a volcano

Question 20

At what plate margins do earthquakes occur?
- how are earthquakes made?

Answer 20

earthquakes occur at:
- destructive
- constructive
- conservative plate margins

earthquakes are always generally caused by the tension that builds up at all three plate margins

Question 21

how are earthquakes caused in a destructive margin?

Answer 21

in a destructive margin the two plates are moving towards each other, it causes earthquakes when:
the tension builds up when one of the plates gets stuck as it moves past the other

Question 22

how are earthquakes caused in a constructive margin?

Answer 22

in a constructive margin the two plates move away from each other
- tension builds along cracks in the plates as they move away from each other

Question 23

how are earthquakes caused in a conservative margin?

Answer 23

in a conservative margin the two plates are moving in the same direction
- tension builds up when the plates are grinding past each other and get stuck

Question 24

what is the process of an earthquake happening?

Answer 24

1. earthquakes are caused by tension that builds up at one of the three plate margins
2. the plates jerk past each other sending out shock waves these vibrations are the earthquake
   3.