Lesson 3.1.5.3

3.1.5.3 Volcanic hazards Quiz: AQA Geography, Unit 1

20 questions

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Lesson 3.1.5.3, Volcanic hazards: 20 multiple choice questions for the AQA Geography (7037), Unit 1: Physical geography, written with Revision Ninja.

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The 20 questions

  1. A nuee ardente is best described as:

    • A slow lava flow of basaltic rock that spreads across the lower slopes and cools gradually on contact with the air
    • A high-altitude cloud of acid rain released by sulphur gas emissions from the crater during a quiet period
    • A fast-moving cloud of hot gas and volcanic debris that flows down a volcano's slopes
    • A river of meltwater that carries rock fragments down valleys after a glacier retreats from the mountainside
  2. Mudflows known as lahars are most often triggered by:

    • Ground subsidence at a caldera, which causes the crater floor to sink and fill with water over several years
    • Gas release from a crater lake with no ash present, which causes the water to become thick and acidic
    • Heavy rain or melting ice mixing with loose volcanic ash and debris
    • Tectonic uplift of continental plates over millions of years, which gradually raises slopes above the snowline
  3. Tephra refers to:

    • Sedimentary rock formed on the floor of the ocean from the slow accumulation of marine shells and debris
    • Gases such as sulphur dioxide and carbon dioxide released from vents and fissures around the volcano
    • Molten rock that cools into a smooth, glassy surface after reaching the surface during a effusive eruption
    • Fragmented material ejected from a volcano, including ash, lapilli and volcanic bombs
  4. Which lava type typically produces the most fluid, far-spreading flows?

    • Andesitic lava from subduction zones that is rich in dissolved gas, which tends to erupt explosively
    • Basaltic lava, low in silica and with low viscosity
    • Pyroclastic lava foam with high viscosity that forms thick, crusted mounds around the vent of the volcano
    • Rhyolitic lava, high in silica and very viscous, so it piles up near the vent rather than spreading far
  5. Why are pyroclastic flows especially dangerous to people?

    • They move slowly down the slopes, giving people time to walk away from the path of the flow
    • They travel at high speed with very high temperatures, causing rapid death by burns and burial
    • They consist only of cold water and mud that causes drowning in valleys below the volcano
    • They are harmless unless they reach the ocean, where they cause steam explosions and tidal waves
  6. Which volcanic gas is most associated with acid rain?

    • Argon, an inert noble gas that is released in small amounts from volcanic vents and does not react
    • Nitrogen, which makes up most of the atmosphere and is released by volcanoes in small quantities
    • Carbon dioxide, which is the most abundant gas released by volcanoes but does not form strong acids
    • Sulphur dioxide, which reacts with water and oxygen to form sulphuric acid in the atmosphere
  7. Most of the world's active volcanoes are found:

    • In the centres of stable continental shields, where the crust is old, thick and very rigid
    • Evenly across the floors of all ocean basins far from plates, where mantle heat rises steadily
    • Only in the Sahara Desert region, where hot dry conditions allow volcanic rock to be exposed at the surface
    • Along plate boundaries, especially around the Pacific Ring of Fire
  8. The Volcanic Explosivity Index (VEI) is:

    • A measure of lava temperature only, which is recorded in degrees Celsius at the vent during an eruption
    • A linear scale that measures earthquake energy release in joules, with each step representing an equal increase
    • A count of the number of deaths caused by eruptions in each region over a decade of records
    • A logarithmic scale in which each step up represents roughly a tenfold increase in erupted material
  9. Which of these is a secondary impact of a volcanic eruption?

    • Famine and disease that follow the loss of harvests and livestock over the following years
    • Burial of homes by a pyroclastic flow that moves downslope at high speed during the eruption
    • Lava destroying a road as it flows across it, cutting off access to the affected communities
    • Direct deaths caused by a nuee ardente that reaches a populated town during the early stages
  10. Which short-term response to volcanic hazard is an example of prediction?

    • Monitoring gas emissions and ground deformation to forecast when an eruption may occur
    • Building lava diversion barriers across valleys that channel flows away from settlements and roads
    • Insuring crops against ash damage so that farmers can recover financially after a major eruption
    • Relocating residents permanently to safer areas several kilometres away from the volcano's flanks
  11. Which of these is a long-term response to volcanic hazard?

    • Air-lifting food supplies after an ash fall that has damaged roads and cut off local communities
    • Land-use zoning that keeps settlement out of high-risk slopes
    • Distributing gas masks to people in the path of an ash plume as it moves across the surrounding area
    • Evacuating residents during an eruption warning, moving them to shelters outside the danger zone quickly
  12. Which of these is an example of adaptation to volcanic hazard?

    • Seeding clouds to disperse ash before it falls onto the surrounding farmland and settlements
    • Diverting lava flows with barriers that channel the molten rock away from towns and key roads
    • Draining crater lakes to remove water that could otherwise mix with ash and form destructive lahars
    • Growing ash-tolerant crops and building stronger roofs
  13. Which effect of ash fallout is most likely to close airports?

    • Ash increasing the lift on aircraft wings, which makes take-off and landing more difficult for pilots
    • Ash clouds damaging aircraft engines and reducing visibility
    • Gas emissions cooling aviation fuel, which makes engines harder to start in the cold air above the volcano
    • Ash damaging runway surfaces only, which can be repaired within a day by ground crews once the ash has settled
  14. Which statement best evaluates the prediction of volcanic eruptions?

    • Eruptions can be predicted exactly to the day with current technology, so no further preparation is needed
    • Monitoring has no value because gas output never changes in any useful way before a major eruption occurs
    • Prediction is irrelevant because all eruptions are small and local, so communities never face serious danger
    • Prediction has improved through monitoring, but timing and scale remain uncertain, so preparedness is essential
  15. The 1980 eruption of Mount St Helens caused much of its damage through:

    • An earthquake that triggered a Pacific-wide tsunami that crossed the ocean and struck distant coastlines
    • Gases that caused global famine within one month of the eruption across the northern hemisphere
    • A lateral blast and lahars that flattened forest and filled rivers with debris
    • Lava flows that destroyed major cities and towns across the surrounding region in the weeks after the event
  16. Ash fall can cause roof collapse mainly because:

    • Ash chemically reacts with timber and metal to weaken them over a period of several weeks
    • Wet ash is heavy, adding a large load to roofs
    • Ash is hot enough to melt roof tiles and timber beams, weakening the structure within a few hours
    • Ash expands greatly in cold weather and pushes against the walls and roof of the building
  17. Which magma type is associated with explosive eruptions at destructive plate margins?

    • Andesitic or rhyolitic magma, high in silica, viscous and gas-rich
    • Cold water-based magma from ocean ridges, which contains dissolved minerals from seawater and erupts gently
    • Basaltic magma, low in silica, which flows freely and produces fast-moving lava rivers at the surface
    • Carbonatite magma from a mantle plume only, which is rare and erupts at very low temperatures
  18. A volcano has been quiet for 50 years. Which information is most useful for assessing the current risk?

    • The colour of the volcano's summit rock as seen from aerial photographs taken during the last decade
    • The number of tourists visiting the area in the current year and the number of hotels open nearby
    • The average temperature of the nearest city across the last ten years of meteorological records
    • Records of past eruptions, including their magnitudes and frequency
  19. A hazard zone is hit by an event on average once every 40 years. What is the chance of an event in any single year?

    • About 1 in 40, or 2.5 per cent
    • About 40 per cent, which would mean an event is expected in roughly two out of every five years
    • About 1 in 4, or 25 per cent, which would mean an event is expected roughly every four years on average
    • About 1 in 400, or 0.25 per cent, which would mean events occur roughly every four centuries
  20. Which landform is typically built by repeated, mainly effusive eruptions at a hotspot?

    • Fold mountain range, formed by the slow compression of sedimentary rock layers between two colliding plates
    • Glacial cirque, a hollow carved into a mountainside by ice and left behind when the glacier melts
    • Sand dune, a mound of wind-blown sand that migrates across desert plains over many years
    • Shield volcano, such as Mauna Loa in Hawaii

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