Volcanic Hazards

Question 1

Constructive margins

Answer 1

Basaltic lava is formed here-very hot and has a low viscosity(runny). Eruptions of basaltic lava are frequent and go on for a long time.

Question 2

Destructive Margins

Answer 2

Acidic lavas are formed here- they are cooler and more viscous(less runny), so flow less easily. Acidic lavas usually erupt every once in a while and are short lived
Because the lava is viscous, it forms blockages in volcanic vents, causing pressure to build. The blockage is cleared by a iolent eruption

Question 3

Pyroclastic Flows

Answer 3

is a mixture of super heated gas, ash and volcanic rock that flows down the sides of a volcano. Travels high speeds(more than 80km/h) and flow long way(10-15km)

Question 4

Volcanic Gases

Answer 4

Lava contains gases such as carbon dioxide and sulfur dioxide, which are released into the atmosphere when a volcano erupts.
Harmful if breathed in

Question 5

Pyroclastic and Ash fallout

Answer 5

is material that has been ejected from a volcano during an eruption
Fallout consists of material of a range of sizes, from large pieces of rock weighing several tonnes to microscopic ash particles. Can travel thousands of kilometres from the volcano
Fine material can form a layer up to several metres in thickness.

Question 6

Mudflows(lahars)

Answer 6

Occur when volcanic material mixes with large amounts of water(from rainfall or from ice melted by eruption).Flows move very quickly(over 80km/h) can travel tens of kilometres.

Question 7

Acid Rain

Answer 7

Volcanic gases can react with water vapour in the atmosphere, which then falls as acid rain

Question 8

Primary Impacts

Answer 8

Direct results of the eruption(people can be killed by falling tephra)