Tectonic Landscapes

Question 1

Explain how volcanoes form at a convergent plate boundary

You may use a diagram in your answer (4)

Answer 1

Melting of oceanic plate produces magma (1).
Collection of magma in magma chamber rises under pressure/less dense than surrounding
rock (1)
Through cracks and joints (1)
Gas/Water Vapour is added to melt (1)
Magma only erupts under great pressure therefore eruptions explosive (1)

Question 2

Explain why some buildings are still standing after an earthquake in Kobe, Japan
(3)

Answer 2

Some buildings are earthquake resistant (1) –example of how buildings are earthquake resistant (1)
Japan = HIC, can afford to protect (1) 
Country is aware of risks posed by earthquakes through 
scientific research (1) 
Modern buildings(1)

Question 3

What is the epicentre?
(1)

Answer 3

The point on the surface, above the focus where most damage occurs (1)
Point where the earthquake first strikes the surface(1)

Question 4

Outline the differences between the Mercalli and the Richter scales (3)

Answer 4

Mercalli measures damage (1)
Richter measures strength/magnitude (1)
Main difference – one is descriptive the other is
quantitative, difference in scales (1)

Question 5

Suggest reasons why people continue to live in areas affected by volcanic eruptions (4)

Answer 5

Fertile soils
-> high crop yield -> income 
Extraction of minerals/metals/crystals 
Tourism 
Geothermal Energy - cheap energy  
Family 
Perceived risk = low

Question 6

Explain the effects of a volcanic eruption or the earthquake on the people and the environment
(6)

Answer 6

Reference to earthquake event or a volcanic eruption

Effects on population, settlement, infrastructure, economy, environment etc

Clear explanation of points
Range of specific facts relating to the effects of the volcanic eruption on the people and their environment and explained points about how the volcanic eruption has been managed.

Question 7

Explain how volcanoes occur at divergent plate boundaries (4)

Answer 7

Magma rises due to convection currents, leading to pressure and doming of the crust (oceanic).

Magma rises through the weaknesses in the crust

Eventually (low viscosity) magma erupts onto the surface

The continued movement of plates pulls the plates apart leading to more effusive eruptions.

Question 8

Compare the characteristic features of convergent plate boundaries and conservative plate boundaries (4)

Answer 8

Convergent plate boundary plates subduction
can lead to earthquake formation (1) due to pressure build up between two plates (1)

Earthquakes also occur at conservative plate boundaries on fault lines (1), but due to tension (1)

Subduction of the oceanic plate leads
to magma formation and explosive volcanic eruptions (1)

No magma is created at conservative plate boundaries (1) therefore there are no volcanic eruptions (1)

Question 9

Why do people continue to live in areas affected by earthquakes?
(3)

Answer 9

Areas may be popular for tourism (1)

Earthquakes could cause landslides, exposing mineral resources which can be mined (1)

Areas may have and emergency plans (1) therefore residents perceive safety (1)

People feel it may not happen to them (1)

Buildings are made to a resistant level therefore
perception of safety (1)

Family and friends (1)

Jobs / work (1)

Question 10

Describe how planning before an earthquake in a LIC could have reduced the effects of this earthquake (3)

Answer 10

Land use planning (1)
Building design (1)
Evacuation (1)
Food and medical (1)

Question 11

Explain the effects of a volcanic eruption or an earthquake (6)

Answer 11

Focus on effects of either volcanic eruption or an earthquake. They should attempt to explain the effects in relation to the event.

An explicit answer with a range of specific and explained points which could be from different examples.

Specific means something like the name of a scheme, a date or a number.

Question 12

Outline one way scientists can measure the magnitude or impact of earthquakes (2)

Answer 12

• Seismometers (1) help pick up seismic waves which can montitor the size of the
  earthquake(1)
• Richter scale (1) can be used to assess the size/ or amount of energy (1)
• Mercalli scale (1) used to assess the damage/ intensity caused by the earthquake (1)
• Use of laser technology (1) to measure movement/ or size of earthquake (1)

Question 13

For an earthquake or volcanic eruption you have studied, explain two effects on people (4)

Answer 13

• Death and injury
• Damage to buildings and infrastructure
• Spread of disease
• Increase in psychological disorders
• Disruption to family life

Question 14

Describe the global distribution of earthquakes (2)

Answer 14

Earthquakes occur at plate boundaries (1).

Earthquakes occur at hotspots (1).

Type of plate boundary (1) development (1) e.g.
at conservative plate margins (1) plates move
past each other (1)

Larger earthquakes occur at convergent plate
boundaries (1).

Earthquakes are found at all plate boundaries
(1).

Examples of plate boundaries/tectonic regions,
e.g. Pacific ring of fire (1).

Question 15

Use an annotated diagram(s) to explain the formation of a hotspot (volcanic island) (4)

Answer 15

Plume of magma rises to the surface, as rising magma is of a lower density to that around it (1)

As the magma reaches the crust it domes the crust (forcing it upwards) -> crust weakening
and allowing magma to reach the surface (1).

Islands build up above the hotspot on the crust until they rise above sea level, due to a series of low viscosity eruptions which build up the
island which is often much wider relative to their height (1)

As the crust moves over the hotspot
the volcanic activity will cease over time, because the route taken by magma is cut causing the volcanic dormancy (1)