AO1 – Knowledge and understanding of the primary and secondary impacts of volcanoes.

AO2 – Application of knowledge and understanding to assess the extent to which the secondary impacts cause greater long-term damage to populations that the primary impacts.

Mark scheme

Level 3 (7 – 9 marks)

AO1 – Demonstrates detailed knowledge and understanding of concepts, processes, interactions and change. These underpin the response throughout.

AO2 – Applies knowledge and understanding appropriately with detail. Connections and relationships between different aspects of study are fully developed with complete relevance. Evaluation is detailed and well supported with appropriate evidence.

Notes for answers

AO1

The nature of vulcanicity and its relation to plate tectonics: forms of volcanic hazard: nuées ardentes, lava flows, mudflows, pyroclastic and ash fallout, gases/acid rain, tephra. Spatial distribution, magnitude, frequency, regularity and predictability of hazard events.
Impacts: primary/secondary, environmental, social, economic, political.
Impacts as evidenced by a recent volcanic event.

AO2

The focus of the response is impact. Cause and response may feature but protracted narrative is unlikely to remain focused upon the question.
There is likely to be a brief distinction made between the two types of hazard. Primary impacts are immediate and arise directly out of the event. Secondary hazards are triggered as a result of the primary hazards and occur in the aftermath.
The main primary hazards are pyroclastic flows. These are accepted as the deadliest of the primary impacts responsible for thousands of deaths worldwide. They are impossible to avoid if a person is in the vicinity this is because they travel with great speed and are highly destructive. The other hazards of lava flows, volcanic gases and tephra generally cause less deaths. Lava flows are much easier to avoid. Tephra is highly dangerous but easier to avoid. Volcanic gases are deadly but only in rare circumstances do they cause death. Some may argue that threats to people includes ash fall on farmland as well as destruction of property by lava flows. This is a legitimate approach.
Historically it is the secondary impacts which have proven most deadly, even generating global impacts.
Lahars are triggered in circumstances where there is rapid ice melt following an eruption. These are perhaps the deadliest of all secondary hazards. Some will point to the impact of the Nevada Del Ruiz eruption in this regard. Floods may also be considered in this context.
Whilst tsunamis are more associated with seismic activity under sea water, they can be triggered by volcanic eruptions also.
There is also a known and clear link to climate change associated with eruptions. Ash clouds from the Pinatubo were shown to reduce global temperatures by up to 1^oC.
Some may point to the substantial economic costs associated with the generation of ash clouds, particularly if air travel is disrupted.
Some may also consider the global impact of a super eruption. Such an event is likely to present catastrophic primary effect in the region but also in terms of the global climatic impact.

If threat is measures by amount of destruction, greatest loss of life and longest recovery time, then it is likely that most will argue secondary hazards posed the greatest threat.

Volcanic Hazards (AQA A Level Geography)

Topic Questions