AQA A-level Geography · 3.1.5

Volcanic hazards

50 exam-style questions with answers for 3.1.5 Volcanic hazards in AQA A-level Geography (spec 7037). Practise with flashcards, a topic quiz, a random quiz across the course, 5 crosswords, or read every question and answer below. Not official AQA material.

All 50 questions and answers

Question 1 · Spec 3.1.5.3 · Nature of vulcanicity
Describe the nature of vulcanicity. [2 marks]
Answer:
The movement of magma, gases and ash from inside the Earth to the surface through vents and fissures (1); it occurs mainly at plate boundaries and above hotspots (1).
Question 2 · Spec 3.1.5.3 · Nature of vulcanicity
Describe the main features of a composite volcano. [3 marks]
Answer:
A steep-sided cone made of alternating layers of ash and lava (1); thick, silica-rich magma that erupts explosively (1); found at destructive margins, for example Mount Fuji or Mount St Helens (1).
Question 3 · Spec 3.1.5.3 · Nature of vulcanicity
Describe the main features of a shield volcano. [3 marks]
Answer:
A broad, gently sloping cone built from many lava flows (1); runny, basaltic lava that erupts fairly gently (1); found at constructive margins and hotspots, for example Mauna Loa and Kilauea (1).
Question 4 · Spec 3.1.5.3 · Nature of vulcanicity
Explain how the viscosity of magma affects the type of eruption. [3 marks]
Answer:
Silica-rich magma is thick and sticky, so gas cannot escape easily (1); pressure builds up and is released as an explosive eruption (1); silica-poor magma is runny, so gas escapes and lava flows out gently (1).
Question 5 · Spec 3.1.5.3 · Forms of hazard
Explain what is meant by a pyroclastic flow (nuée ardente). [3 marks]
Answer:
A fast-moving, dense cloud of hot gas, ash and rock fragments (1); it travels down the slopes of a volcano at over 100 km/h (1); temperatures of several hundred degrees Celsius destroy everything in its path (1).
Question 6 · Spec 3.1.5.3 · Forms of hazard
Explain why lava flows cause damage but rarely kill people. [3 marks]
Answer:
Lava moves slowly, so people can usually escape (1); runny basaltic lava can travel long distances, burying roads and buildings (1); fires start and farmland is destroyed (1).
Question 7 · Spec 3.1.5.3 · Forms of hazard
Explain how a lahar forms. [3 marks]
Answer:
Volcanic ash and debris mix with water from rain, melted ice and snow, or a crater lake (1); the mixture flows rapidly down river valleys like wet concrete (1); lahars can travel tens of kilometres and may occur long after the eruption (1).
Question 8 · Spec 3.1.5.3 · Forms of hazard
Explain why lahars can be so deadly. [3 marks]
Answer:
They move fast and with little warning (1); they bury or sweep away settlements in valleys (1); for example, in 1985 a lahar from Nevado del Ruiz in Colombia buried the town of Armero and killed about 23,000 people (1).
Question 9 · Spec 3.1.5.3 · Forms of hazard
Describe the hazards caused by ash fall. [4 marks]
Answer:
Wet ash is heavy and can collapse roofs (1); ash damages crops and contaminates water supplies (1); breathing ash causes respiratory problems (1); ash clouds ground aircraft and cause power and transport disruption (1).
Question 10 · Spec 3.1.5.3 · Forms of hazard
Explain what is meant by tephra. [2 marks]
Answer:
All solid material thrown into the air during an eruption (1); it ranges from fine ash to lapilli and large volcanic bombs (1).
Question 11 · Spec 3.1.5.3 · Forms of hazard
Describe the hazards caused by volcanic gases. [3 marks]
Answer:
Sulphur dioxide dissolves in water and falls as acid rain, damaging crops and buildings (1); carbon dioxide is heavier than air and can suffocate people and animals in low places (1); hydrogen sulphide and other gases are poisonous (1).
Question 12 · Spec 3.1.5.3 · Forms of hazard
Explain what a jökulhlaup is. [2 marks]
Answer:
A sudden flood caused by volcanic heat melting glacier ice (1); the huge volume of meltwater flows rapidly, washing away roads and bridges, as in Iceland (1).
Question 13 · Spec 3.1.5.3 · Forms of hazard
Explain how a volcanic eruption can cause a tsunami. [2 marks]
Answer:
An explosive eruption, collapse of a volcano flank or pyroclastic flows entering the sea displaces large volumes of water (1); waves spread out and flood coasts, as after Krakatoa in 1883 (1).
Question 14 · Spec 3.1.5.3 · Distribution and magnitude
Describe the distribution of active volcanoes. [3 marks]
Answer:
Most are on the Pacific Ring of Fire (1); others lie along the mid-ocean ridges and the Alpine–Himalayan belt (1); a few are above hotspots, such as Hawaii and Yellowstone (1).
Question 15 · Spec 3.1.5.3 · Distribution and magnitude
Describe the Volcanic Explosivity Index. [3 marks]
Answer:
A scale from 0 to 8 that measures the size of an eruption (1); based on the volume of material erupted and the height of the eruption column (1); each step represents about ten times more erupted material (1).
Question 16 · Spec 3.1.5.3 · Distribution and magnitude
An eruption has a VEI of 5. Calculate how many times more material it ejects than an eruption with a VEI of 3. [2 marks]
Answer:
Each VEI step is about ten times larger (1); 10 × 10 = about 100 times more (1).
Question 17 · Spec 3.1.5.3 · Distribution and magnitude
Explain the relationship between the frequency and magnitude of volcanic eruptions. [2 marks]
Answer:
Small eruptions with a low VEI occur often, sometimes daily or yearly (1); very large eruptions, with a VEI of 7 or 8, are rare and may occur every thousands of years (1).
Question 18 · Spec 3.1.5.3 · Prediction
Describe how volcanoes are monitored. [4 marks]
Answer:
Seismometers detect the earthquake swarms that come with rising magma (1); tiltmeters, GPS and satellite radar measure the bulging of the ground (1); gas sensors measure increases in sulphur dioxide (1); thermal imaging and ground temperature sensors detect heating (1).
Question 19 · Spec 3.1.5.3 · Prediction
Explain why volcanoes are easier to predict than earthquakes. [2 marks]
Answer:
Rising magma gives warning signs over days, weeks or months (1); earthquakes give few reliable signals before they occur (1).
Question 20 · Spec 3.1.5.3 · Prediction
Explain why it is still difficult to predict volcanic eruptions accurately. [3 marks]
Answer:
Some volcanoes are dormant for centuries, so there is little data (1); warning signs can be false alarms, so evacuations can be costly and unnecessary (1); the size and type of eruption cannot be forecast with certainty (1).
Question 21 · Spec 3.1.5.3 · Prediction
Explain the role of volcano observatories. [2 marks]
Answer:
They monitor volcanoes constantly and interpret the data (1); they advise authorities on alert levels, evacuation and hazard maps (1).
Question 22 · Spec 3.1.5.3 · Impacts
Distinguish between primary and secondary impacts of a volcanic eruption. [4 marks]
Answer:
Primary impacts are caused directly by the eruption, such as deaths from pyroclastic flows (1); and buildings buried by ash or lava (1); secondary impacts are caused afterwards, such as lahars and disease (1); and food shortages and loss of income after crops are damaged (1).
Question 23 · Spec 3.1.5.3 · Impacts
Describe the environmental impacts of volcanic eruptions. [3 marks]
Answer:
Lava and ash destroy vegetation and habitats (1); acid rain and ash pollute soil, rivers and lakes (1); new land forms, and ash adds nutrients that make soil fertile in the long term (1).
Question 24 · Spec 3.1.5.3 · Impacts
Describe the social impacts of volcanic eruptions. [3 marks]
Answer:
Deaths and injuries from flows, ash and gases (1); people lose homes and are displaced to temporary shelters (1); schools and health services are disrupted, and there is stress and trauma (1).
Question 25 · Spec 3.1.5.3 · Impacts
Describe the economic impacts of volcanic eruptions. [3 marks]
Answer:
Buildings, roads and farmland are destroyed, with high repair costs (1); businesses, farming and tourism lose income (1); air travel is disrupted and trade is affected (1).
Question 26 · Spec 3.1.5.3 · Impacts
Describe the political impacts of volcanic eruptions. [3 marks]
Answer:
Governments may be criticised for poor warnings or slow help (1); money has to be diverted to relief and rebuilding (1); international aid and co-operation may be needed, or tensions can rise over resettlement (1).
Question 27 · Spec 3.1.5.3 · Impacts
Explain how large volcanic eruptions can affect global climate. [3 marks]
Answer:
Sulphur dioxide is thrown into the stratosphere (1); it forms sulphate aerosols that reflect sunlight (1); global temperatures fall for one or two years, as after Pinatubo in 1991 (1).
Question 28 · Spec 3.1.5.3 · Responses
Describe the short-term responses to a volcanic eruption. [3 marks]
Answer:
Evacuate people and set up exclusion zones (1); provide emergency shelters, food, water and medical care (1); issue masks and advice on ash, and close airspace if needed (1).
Question 29 · Spec 3.1.5.3 · Responses
Describe the long-term responses to a volcanic eruption. [3 marks]
Answer:
Rebuild homes and infrastructure, or resettle people (1); improve monitoring and warning systems (1); update hazard maps and land-use planning (1).
Question 30 · Spec 3.1.5.3 · Responses
Explain how preparedness reduces the impact of volcanic hazards. [2 marks]
Answer:
Hazard maps, evacuation plans and regular drills prepare people to act quickly (1); emergency supplies and shelters are ready before an eruption (1).
Question 31 · Spec 3.1.5.3 · Responses
Explain how mitigation reduces the impact of volcanic hazards. [2 marks]
Answer:
Reinforced roofs and steep roof slopes shed ash (1); barriers and channels divert lahars and flows away from settlements (1).
Question 32 · Spec 3.1.5.3 · Responses
Explain how lava flows can be controlled. [3 marks]
Answer:
Barriers and channels can steer lava away from settlements (1); spraying water cools lava so that it solidifies and forms a barrier, as at Heimaey in Iceland in 1973 (1); explosives have been used to divert flows on Mount Etna (1).
Question 33 · Spec 3.1.5.3 · Responses
Explain how the risk from lahars can be reduced. [3 marks]
Answer:
Dams and channels trap or direct lahars (1); sensors and sirens warn people downstream (1); building is restricted in valleys at risk (1).
Question 34 · Spec 3.1.5.3 · Responses
Explain why volcanic eruptions cannot be prevented. [2 marks]
Answer:
The processes that drive eruptions deep inside the Earth are far too powerful to control (1); only the impacts can be reduced, by preparing, mitigating and adapting (1).
Question 35 · Spec 3.1.5.3 · Responses
Explain why people continue to live near active volcanoes. [3 marks]
Answer:
Volcanic soils are fertile and support farming (1); volcanoes provide jobs from tourism and geothermal energy (1); people may lack the money to move or have family ties, or they underestimate the risk (1).
Question 36 · Spec 3.1.5.3 · Recent events
Eyjafjallajökull, Iceland, 2010: describe the main hazards and why the eruption caused such wide disruption. [3 marks]
Answer:
A large plume of fine ash was thrown high into the atmosphere (1); winds carried it over northern Europe, where ash can damage aircraft engines (1); airspace was closed for several days, cancelling around 100,000 flights (1).
Question 37 · Spec 3.1.5.3 · Recent events
Eyjafjallajökull, Iceland, 2010: describe the economic and social impacts. [3 marks]
Answer:
Airlines lost an estimated $1.7 billion (1); millions of passengers were stranded, and supplies of fresh imports were delayed (1); local farmers were evacuated and farmland covered in ash, and flooding from melted glacier ice damaged roads (1).
Question 38 · Spec 3.1.5.3 · Recent events
Eyjafjallajökull, Iceland, 2010: describe how authorities responded. [3 marks]
Answer:
Airspace was closed on the advice of ash forecasts (1); research flights and measurements led to safe limits for ash concentration (1); airspace reopened in stages, based on those limits (1).
Question 39 · Spec 3.1.5.3 · Recent events
Kilauea, Hawaii, 2018: describe the nature of the eruption and its impacts. [4 marks]
Answer:
Fissures opened in the Lower East Rift Zone in the Leilani Estates area (1); runny basaltic lava flowed slowly for months (1); about 700 homes and farmland were destroyed (1); no one was killed by lava, because people could escape, and about 2,000 people were evacuated (1).
Question 40 · Spec 3.1.5.3 · Recent events
Kilauea, Hawaii, 2018: describe the responses. [3 marks]
Answer:
The USGS Hawaiian Volcano Observatory monitored and issued alerts (1); residents were evacuated and shelters opened (1); federal disaster aid was provided and the lava flows were mapped to plan evacuation (1).
Question 41 · Spec 3.1.5.3 · Recent events
Fuego, Guatemala, 2018: describe the hazards and the impacts. [4 marks]
Answer:
An explosive eruption produced pyroclastic flows down the slopes (1); the flows hit villages such as El Rodeo and San Miguel Los Lotes with little warning (1); well over 100 people were killed and hundreds were missing (1); ash fall closed the main airport and damaged crops (1).
Question 42 · Spec 3.1.5.3 · Recent events
Fuego, Guatemala, 2018: evaluate why the death toll was so high. [3 marks]
Answer:
The volcano erupts often, so people had become used to the activity and underestimated the risk (1); warnings were slow to reach people, and evacuation orders came late (1); poor communities lived close to the volcano on fertile land, with few routes away (1).
Question 43 · Spec 3.1.5.3 · Recent events
La Palma, Canary Islands, 2021: describe the nature of the eruption and its impacts. [4 marks]
Answer:
The Cumbre Vieja volcano erupted on 19 September 2021, and the eruption lasted about 85 days (1); lava flows destroyed nearly 3,000 buildings (1); banana plantations and roads were buried (1); about 7,000 people were evacuated, but there were no direct deaths (1).
Question 44 · Spec 3.1.5.3 · Recent events
La Palma, Canary Islands, 2021: describe the responses. [3 marks]
Answer:
Evacuation of threatened villages ahead of the lava (1); the Spanish government and the EU gave financial aid and housing support (1); monitoring of earthquakes, gas and ground deformation continued (1).
Question 45 · Spec 3.1.5.3 · Recent events
Hunga Tonga–Hunga Haʻapai, 2022: describe the hazards and impacts. [3 marks]
Answer:
A huge explosive eruption on 15 January 2022 sent ash and gas tens of kilometres into the atmosphere (1); tsunami waves hit Tonga and crossed the Pacific, and a few people died (1); ash covered islands, damaged water supplies and farmland, and the undersea cable was cut, isolating the islands (1).
Question 46 · Spec 3.1.5.3 · Recent events
Mount Pinatubo, Philippines, 1991: explain how prediction reduced the death toll. [3 marks]
Answer:
Scientists detected increased earthquakes and gas emissions in the weeks before the eruption (1); a series of alert levels were issued, and tens of thousands of people were evacuated (1); hundreds still died, mainly from roofs collapsing under wet ash, but the toll would have been much higher without evacuation (1).
Question 47 · Spec 3.1.5.3 · Recent events
Compare the impacts of Kilauea in 2018 and Fuego in 2018. [4 marks]
Answer:
Kilauea's runny basaltic lava moved slowly, so there was no loss of life (1); Fuego's pyroclastic flows moved very fast and killed many people (1); Kilauea's damage was mainly economic, with homes lost (1); Fuego's poorer communities had less warning and fewer resources to respond (1).
Question 48 · Spec 3.1.5.3 · Recent events
Explain why the impacts of eruptions of similar size can differ between places. [3 marks]
Answer:
Eruption type, such as pyroclastic flow or lava flow, affects how people can escape (1); population density and level of development affect exposure and vulnerability (1); the quality of monitoring, warning and emergency response varies (1).
Question 49 · Spec 3.1.5.3 · Responses
Explain how a volcanic hazard zone map is used. [2 marks]
Answer:
It shows areas at risk from lava, pyroclastic flows, lahars and ash fall (1); authorities use it to plan evacuation routes and to restrict building in the most dangerous zones (1).
Question 50 · Spec 3.1.5.3 · Impacts
Describe the benefits that volcanic activity can bring. [3 marks]
Answer:
Any three from: fertile soils for farming (1); geothermal energy for heating and electricity (1); minerals and building materials (1); tourism (1); new land formed by lava (1).

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