Supervolcanoes & Calderas

Question 1

What is a Super Eruption ?

Answer 1

Short term explosive events that eject about 10^13 kg of magma (VEI 8)

Question 2

What conditions are needed for a Super Eruption?

Answer 2

1. Very large volume of magma with strong explosive potential
   ( High volatile (gas) content and high viscosity)
2. Enormous amount of eruptive magma that accumulates in shallow chambers.

Question 3

Supervolcanoes

Answer 3

Volcano producing at least one explosive super eruption

Question 4

Why is high viscocity important in super eruption?

Answer 4

They inhibit escape of bubbles from magma.
(Ran by mainly water)

Question 5

Why doesn’t the Magma cool and solidify in Super Volcano system?

Answer 5

Deeper level, hotter, Mafic magma continually rises in system. Provides thermal energy that drives the super volcano system.

Question 6

How do Supervolcanoes erupt?

Answer 6

1. New, hotter magma is injected in system.
2. Earthquakes and Faulting fractures Chamber wall.
3. This causes overpressure due to exsolving.

Question 7

What are Caldera forming Super eruptions?

Answer 7

Super Eruptions that are upward due to magma intrusion. Ring fractures cause eruption to eject high into atmosphere.

Question 8

Order of Caldera Structure from Top to Below

Answer 8

1. Roof
2. Low Dense Rhyolite
3. Partially Crystallized Mush
4. High Dense Molten Basalt

Question 9

True or False: Super Eruptions can be both hotspot and subduction zone under thick continental crust.

Answer 9

True

Question 10

What are the Post-Caldera forming Eruptive Activity?

Answer 10

Possible formation of lake, Erosion, Uplift of Caldera floor, Effusive Eruptions (dome collapse, lava flows), Smaller Explosive Eruptions (ash fall, pyroclastic flows)

Question 11

Resurgent Dome

Answer 11

Up-warded caldera floor due to reintrusion of magma beneath caldera.