Hazardous Earth

Question 1

What’s the name of the model that describes how air circulates between low and high-pressure belts as a result of differing conditions at different latitudes?

Answer 1

Global atmospheric circulation model.

Question 2

At what latitude does cold air from the poles meet warm surface winds?

Answer 2

60°

Question 3

What do we call surface winds that blow in the direction of the equator?

Answer 3

Trade winds

Question 4

Tropical storms rotate in the same direction in both hemispheres. T/F and why?

Answer 4

False - they rotate in different directions.
They spin anti-clockwise in the Northern hemisphere and clockwise in the Southern hemisphere.

Question 5

At what latitude does cool air sink?

Answer 5

30°

Question 6

What direction do trade winds blow in the southern hemisphere?

Answer 6

From the south-east.

Question 7

In what direction do westerlies blow?

Answer 7

Towards the poles.

Question 8

At what latitude does cold air from the poles meet the warm surface winds, causing the warmer air to rise and forms a low-pressure belt?

Answer 8

60°

Question 9

Suggest
why the UK is not threatened by tropical storms. [4 marks]

Got 2/4 on March 29th

Answer 9

• Tropical storms need energy to grow and sustain themselves and they get this from seas hotter than 26.5°C. (1)
• The hot sea also provides evaporated moisture that forms clouds and rain. (1)
• The higher the temperatures of the oceans, the more energy tropical storms will accumulate, the greater the intensity of the storm. (1)
• However, the seas around the UK rarely, if ever, reach these temperatures and so tropical storms cannot form. (1)

Question 10

Describe
what is meant by the term ‘carbon capture and storage’.

Got 1/2 on March 29th

Answer 10

‘Carbon capture and storage’ refers to the removal of CO₂ from the emissions by thermal power stations (1) and its storage in large underground cavities such as used oil and gas wells. (1)

Question 11

How thick is oceanic crust?

Answer 11

5 - 8 km thick.

Question 12

How thick is continental crust?

Answer 12

30 - 40km thick.

Continental crust can reach 70km under some mountain belts e.g. the Himalayas.

Question 13

What sort of rock is oceanic crust made out of?

Answer 13

Basaltic rock.

Question 14

What sort of rock is continental crust made out of?

Answer 14

Granitic rock.

Question 15

How dense is oceanic crust?

Answer 15

3g/cm³.

Question 16

How dense is continental crust?

Answer 16

2.7g/cm³.

Question 17

Which type of crust is older?

Answer 17

Continental crust.

Question 18

What type of currents are responsible for moving tectonic plates?

Answer 18

Convection currents.

Question 19

What 2 sources provide energy for the Earth’s convection currents?

Answer 19

• Radioactive decay
• Residual heat

Question 20

How is energy generated in the core from radioactive decay?

Answer 20

The radioactive decay of naturally occurring chemical elements (e.g. uranium) releases energy in the form of heat.

Question 21

How is energy generated in the core from residual heat?

Answer 21

Residual heat is left over from the Earth’s formation.

Question 22

What are products of volcanic eruptions?

Answer 22

• Lava (including lava bombs)
• Ash clouds
• Pyroclastics flows
• Gases (e.g. CO₂ and SO₂)

Question 23

Define a lava bomb.

Answer 23

Fragments of molten lava that are blown out of a volcano in an eruption.

Question 24

Define tephra.

Answer 24

Any solid material thrown into the air during a volcanic eruption, ranging from ash (less than 2mm in diameter) to lava bombs (over 64mm).

Question 25

Define a pyroclastic flow.

Answer 25

A deadly super-heated (hot) mixture of broken rocks (tephra) & gases that run down the sides of a volcano.

Pyroclastic flows are also known as nuée ardentes.

Question 26

Explain why pyroclastic flows can be so dangerous.

Answer 26

They can travel long distances and destroy everything in their path.

Question 27

What do we call locations in which a hot mass of
rising heat can be found under a weakness in a
tectonic plate?

Answer 27

Hot spot

Question 28

Define a hot spot.

Answer 28

A part of the Earth’s crust where plumes (‘clouds’) of magma rise, which weakens the crust.
They are usually away from plate boundaries.

Question 29

What do we call the mudflows generated as secondary effects of eruptions?

Answer 29

Lahars.

Question 30

Define a lahar.

Answer 30

Mudflows that occur when tephra mixes with water, either from rainfall or from melted snow & ice.

Question 31

What scale is now used to measure earthquakes after the Richter scale?

Answer 31

Moment Magnitude Scale.

Question 32

Explain why heat energy is the key to plate tectonics. [4 marks]

Answer 32

In convection, hot things that are less dense and have more energy rise. (1) Convection currents happen in the upper mantle. (1) The core is hot and heats rock to a molten state. (1) This heated rock rises and hits the underside of the plate and causes the plates to move. (1)

Question 33

Explain why the qualities of the rocks at a plate boundary affect the magnitude of the earthquakes produced. [4 marks]

Answer 33

If the rocks at a conservative or destructive boundary are very strong (1), they are able to withstand the pressures caused by plate movements for longer (1). As a consequence, when the rock does finally fail, much more energy is released and so the earthquake is bigger (1). If the rocks are rougher, then there will be more friction at the boundary so the earthquake will be bigger (1).

Question 34

Explain why the secondary effects of volcanoes are sometimes worse than the primary effects.

Answer 34

Ash can cause a volcanic winter (1) by entering the upper atmosphere and reflecting sunlight. This causes cooling of around 2-4°C. This can cause famine (1) as crops don’t ripen and so more people are affected across a wider area. (1)

Lahars can destroy everything in their path (1) , including buildings, homes, workplaces, preventing people from going to work (1) and stalling economic development. (1)

Tsunamis inundate the land with sea water ruining the productivity of farmland (1) and destroying infrastructure and places of work (1) which prevents money being earned. (1)

Question 35

State what is meant by Fair Trade. [1 mark]

Answer 35

When primary producers (farmers) receive a fixed price above the market rate. (1)

Question 36

Which part of the UK has the wettest climate? Explain why.

Compass point

Answer 36

West.
Air masses arriving from the Atlantic carry a lot of moisture. The western side of the UK has a lot of mountains which push the air masses upwards so they cool down and drop the moisture as precipitation.