Podcast
Questions and Answers
Which factor primarily determines whether a volcanic eruption will be effusive or explosive?
Which factor primarily determines whether a volcanic eruption will be effusive or explosive?
- The age of the volcano.
- The color of the surrounding rocks.
- The volcano's height above sea level.
- The amount of gas in the magma and its viscosity. (correct)
Pyroclastic flows are considered extremely hazardous due to what primary characteristic?
Pyroclastic flows are considered extremely hazardous due to what primary characteristic?
- Their low temperature.
- The difficulty in direct measurements due to the danger. (correct)
- The minimal environmental impact they have.
- The ease in which they can be directly measured.
What is the underlying principle that causes magma to rise through the Earth's crust?
What is the underlying principle that causes magma to rise through the Earth's crust?
- The magnetic pull from the Earth's core.
- The rotation of the Earth.
- The chemical reactions between magma and the crust.
- Magma has a lower density than the surrounding rocks. (correct)
During an explosive volcanic eruption, ash clouds can reach significant heights in the atmosphere. Which atmospheric layer do they typically reach?
During an explosive volcanic eruption, ash clouds can reach significant heights in the atmosphere. Which atmospheric layer do they typically reach?
Which of the following is NOT a direct product of an explosive volcanic eruption?
Which of the following is NOT a direct product of an explosive volcanic eruption?
What role does gas play in determining the type of volcanic eruption?
What role does gas play in determining the type of volcanic eruption?
Which of the following analogies best describes the mechanism behind an explosive volcanic eruption?
Which of the following analogies best describes the mechanism behind an explosive volcanic eruption?
What distinguishes an effusive eruption from an explosive eruption in terms of magma viscosity?
What distinguishes an effusive eruption from an explosive eruption in terms of magma viscosity?
When a volcano erupts Kilometer cubed quantities of magma and sends ash clouds high into the stratosphere, what kind of impact could this have?
When a volcano erupts Kilometer cubed quantities of magma and sends ash clouds high into the stratosphere, what kind of impact could this have?
What geological feature is defined as a vent or 'chimney' connecting molten rock from within the Earth’s crust to the Earth's surface, including the surrounding cone of erupted material?
What geological feature is defined as a vent or 'chimney' connecting molten rock from within the Earth’s crust to the Earth's surface, including the surrounding cone of erupted material?
Flashcards
What is a volcano?
What is a volcano?
A vent connecting molten rock (magma) from Earth’s crust to the surface, including the surrounding cone of erupted material.
Effusive Eruptions
Effusive Eruptions
Eruptions characterized by lava flowing onto the ground.
Products of Explosive Eruptions
Products of Explosive Eruptions
Ash fall, pyroclastic flow, and volcanic bombs.
Why Magma Rises
Why Magma Rises
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Eruption Style Factors
Eruption Style Factors
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Explosive Eruption Conditions
Explosive Eruption Conditions
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Effusive Eruption Conditions
Effusive Eruption Conditions
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Study Notes
- A volcano is a vent or chimney that connects molten rock (magma) from within the Earth’s crust to the Earth's surface, including the surrounding cone of erupted material.
- Effusive eruptions are characterised by outpourings of lava onto the ground.
- Direct measurements of pyroclastic flows are extremely dangerous.
- Three products from an explosive eruption include, ash fall, pyroclastic flow and volcanic bombs.
- Explosive volcanic eruptions can be catastrophic.
- They can erupt 10’s-1000’s km3 of magma
- Send ash clouds >25 km into the stratosphere
- Have severe environmental and climatic effects making them hazardous.
- Hot, molten rock (magma) is buoyant with a lower density than surrounding rocks and will rise through the crust to erupt on the surface, similar to how a hot air balloon works.
- When magma reaches the surface, the eruption style depends on its flow ease and gas content (H2O, CO2, S).
- Large amounts of gas and a high viscosity (sticky) magma will form an explosive eruption.
- Small amounts of gas and (or) low viscosity (runny) magma will form an effusive eruption where the magma just trickles out creating a lava flow.
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