Extrusive volcanic activity

Question 1

What are the three main types of lava?

Answer 1

Basaltic lava (made at constructive plate margins)
Andesitic lava (made at destructive plate margins)
Rhyolitic lava (made at destructive plate margins)

Question 2

What is the silica content, viscosity, and temperature of eruption for basaltic lava?

Answer 2

Silica content - low
Viscosity - low (runny)
Temperature of eruption - over 950°C (1100-1200°C)

Question 3

What is the silica content, viscosity, and temperature of eruption for andesitic lava?

Answer 3

Silica content - medium
Viscosity - medium
temperature of eruption - 750-950°C

Question 4

What is the silica content, viscosity, and temperature of eruption for rhyolitic lava?

Answer 4

Silica content - high
Viscosity - high (thick and sticky)
Temperature of eruption - less than 750°C

Question 5

What are eruptions of basaltic lava like? why is this?

Answer 5

They aren’t violent, the eruptions are frequent and occur over long periods of time because it flows easily and gas can escape from it easily

Question 6

What are eruptions of andesitic and rhyolitic lava like? Why is this?

Answer 6

They are violent, the eruptions are intermittent and short-lived because they flow less easily and gas can’t escape from it easily. So pressure builds up because of lava blockages and trapped gases.