Volcanic hazards

Question 1

List the features of constructive volcanic eruptions.

Answer 1

1= Basaltic lava
2= Low viscosity
3= Frequent but not violent
4= Ocean ridges or rift valleys

Question 2

List the features of destructive volcanic eruptions.

Answer 2

1= Andesitic and rhyolitic lava
2= Cooler and viscous
3= Intermittent and short lived - ‘clearing the throat’
4= Blockages at subduction zones
5= Violent and explosive

Question 3

What does it mean by basaltic lava.

Answer 3

Basaltic lava is very hot and has low viscosity (runny) so it flows easilly and quickly. It causes eruptions which are frequent, long lasting but not very violent - at constructive margins.

Question 4

What does it mean by viscosity of lava.

Answer 4

Viscous lava is less runny, and thick. It can cause blockages in subduction zones causing pressure to build, and cleared by a violent eruption.

Question 5

What type of eruptions are found at magma plumes?

Answer 5

They usually have basaltic lava that flows quickly, forming volcanoes with gentle slopes.

Question 6

List some volcanic hazards.

Answer 6

1= Pyroclastic flows
2= Lava flows
3= Volcanic gases
4= Pyroclastic and ash fallout
5= Mudflows (lahars)
6= Acid rain

Question 7

Explain the hazard of pyroclastic flows.

Question 8

Explain the hazard of lava flows.

Question 9

Explain the hazard of volcanic gases.

Question 10

Explain the hazard of pyroclastic and ash fallout.

Question 11

Explain the hazard of mudflows (lahars).

Question 12

Explain the hazard of acid rain.