Violent Eruptions
Quite Eruptions
Locations of Eruptions
Volcanoes in Depth
The major volcanoes
100
What happens during a violent eruption?
Lava and gases fly into the air like a soda bottle being opened.
100
What is the meaning of a quite volcano?
Non vicious lava making great flows of lava that build sloping deposits.
100
At what type of plate boundaries do volcanoes form?
Volcanoes usually form where tectonic plates are either diverging or converging.
100
Why is it important to monitor volcanoes?
The United Statescontain 169 geologically active volcanoes, of which 54 volcanoes are a very high or high threat to public safety.
100
What is a shield volcano?
Shield volcanoes are built almost entirely of fluid lava flows, a broad, gently sloping cone of flat, dome shape.
200
Name one thing that occurs before the eruption?
Magma often collects in a pocket called a magma chamber.
200
Name on type of quite eruption volcano.
Shield Volcano.
200
Name 3 ways that volcanoes form.
Subduction Zone volcanoes Mid-ocean rift volcanoes Hot Spot volcanoes
200
What kinds of unusual activity might be noticed before an eruption?
Common symptoms of volcanic unrest include an increase in the frequency or intensity of earthquakes beneath a volcano.
200
What are composite volcanoes?
They are typically steep-sided, symmetrical cones of large dimension built of alternating layers of lava flows, volcanic ash, and cinder blocks.
300
How can you tell the difference of a quite and violent volcano?
Based off of its characteristics
300
Describe a shield volcano.
Shield volcanoes are broad, gently sloping volcanic mountains. Their eruptions consist of hot flowing basaltic lava that travels a long way before it solidifies.
300
Explain what a subduction zone is and how it forms a volcano.
Subduction Zone volcanoes form at the boundaries of two plates, one overriding the other.
300
Is there evidence for a cause and effect relationship between eruptions that occur at about the same time?
No.
300
What are cinder cone volcanoes?
Cinder cones are the simplest type of volcano. They are built from particles and blobs of hardened lava released from a single vent.
400
What determines how vicious a volcano is?
The temperature and composition
400
What are the two main reasons volcanoes erupt?
1) The magma deep under the crust is less dense than the surrounding rock causing it to rise. 2) As the magma approaches the surface of the Earth the gas that is in the magma will come bubbling out because the pressure surrounding the magma will decrease nearer the surface.
400
Describe how a Mid-ocean rift forms a volcano.
Mid-ocean rift volcanoes form where two oceanic plates are spreading apart.
400
Can mantle plumes increase activity in volcanoes?
yes.
400
Compare and contrast a shield volcano to a composite volcano.
Shield volcanoes are built almost entirely of fluid lava flows, a broad, gently sloping cone of flat, dome shape. Composite volcanoes are typically steep-sided, symmetrical cones of large dimension built of alternating layers of lava flows, volcanic ash, and cinder blocks.
500
Describe how it would feel like if you lived near a major volcano.
Based on imagination.
500
What is the primary number of eruption types?
Six.
500
Compare and Contrast a Mid-ocean rift volcanoes to Subduction Zone volcanoes.
Subduction Zone volcanoes form at the boundaries of two plates, one overriding the other. Mid-ocean rift volcanoes form where two oceanic plates are spreading apart.
500
Can an eruption at one volcano trigger an eruption at another nearby volcano
Yes, it is possible. However there are a few historic examples of simultaneous eruptions from volcanoes or vents located within about 10 km of each other, but it's very difficult to determine whether one might have caused the other.
500
How high are most composite volcanoes?
estimated around 8,000 ft.
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