AQA A Level Volcanic Hazards

What percentage of volcanic eruptions occur near plate boundaries?

• 95%

• 75%

• 65%

• 55%

What are the three types of magma?

• Rhyolitic

• Andesitic

• Basaltic

• Ooilitic

• Dolomitic

Which of these is not a characteristic of Rhyolitic magma.

• It is viscous

• Low silica content

• Coagulates in the main vent

• Explosive, dangerous eruptions

Which of these is NOT a characteristic of Basaltic magma?

• Low viscosity

• Low silica content (45%-55%)

• Effusive Eruptions (non explosive)

• High gas content

Which is not true about Tephra?

• It travels away from the volcano

• In is over 2mm in diameter

• It is material ejected from the volcano

• Can rise up to 100km

What is created when the column of ejected material collapses?

• Nuée ardentes

• Pyroclastic Flow

• Pyroclasts

• Lahars

What hazard is the second most dangerous threat to live from a volcanic eruption?

• Lava

• Nuée ardentes

• Pyroclastic Flows

• Lahars

How does a Lahar form?

• When people have farmed the volcano slopes and the lava mixes with the soil

• When the local geology is unconsolidated material

• When rain falls on an extinct volcano and combines with the sediment there

• When water from rivers, snow-capped volcanoes or crater lakes mixes with rock fragments and volcanic ash

Mauna Loa, Kilauea and Hualalai have exhibited this type of eruption.

• Explosive Eruption

• Effusive eruption

• Nuée ardentes

• Tephra Eruption

As well as erupting rock, tephra and ash, volcanoes eject huge amounts of volcanic gases including hydrochloric acid and sulphur dioxide. Which of these is sulphur dioxide NOT responsible for?

• Acid Rain - combining with water to form sulphuric acid

• Ozone depletion - sulphuric acid triggers ozone depletion in the stratosphere

• Air pollution - breathing problems for those downwind

• Increases the intensity of storms - acid in the atomsphere fuels the formation of storms

• Reduce solar radiation - sulphuric acid can reflect sunlight