Show:
Volcanoes and Plate Tectonics
Inside Volcanoes
Types of Volcanoes
Volcanic Landforms
Other Volcanic Info
100
The large circle of Volcanoes in the Pacific Ocean is called
the Ring of Fire
100
How is a quiet eruption different than an explosive eruption?
A quiet eruption results in oozing lava, whereas an explosive eruption is loud and results in ash and cinder exploding into the atmosphere.
100
This type of volcano primarily is formed by oozing lava:
Shield Volcano
100
The inside of a volcano where the magma collects in a pocket is called a magma _____________.
Chamber
100
How do gases in the mantle and crust affect magma?
Gases exert increasing pressure as they rise and push the magma towards the surface.
200
Describe what can occur at a colliding (or converging) boundary.
One plate could subduct under another, creating a deep ocean trench. As the plate is subducting, it will start to melt which will produce magma that rises towards the surface making volcanoes. or Plates could compress together and create folds and mountain ranges.
200
What is the difference between magma and lava?
Magma is molten rock under the surface of the earth and it turns into lava once it reaches the surface.
200
What causes all three types of volcanoes to grow bigger?
After a volcano erupts, new layers of lava cool on top of the old layers, increasing the height.
200
How does a batholith form?
A large mass of magma cools inside the crust and forms a gigantic rock. Often the rocks are pushed up towards the surface over time and they form the core of many mountain ranges.
200
Describe how viscosity can affect the shape a volcano takes on.
Low viscosity lava is very runny and will ooze out and spread far before it has a chance to cool, making a wide flat volcano (shield volcano) whereas high viscosity lava is sticky and once it comes out of a volcano it moves very slowly and cools before having a chance to spread out, making a narrow and steep volcano like a cinder cone or a composite volcano.
300
Where on tectonic plates do most volcanoes form?
On the plate boundaries or edges.
300
What are two things that happen to magma when it heats up?
When magma is heated, its viscosity decreases and it becomes more runny/quicker. Its density also decreases when it heats up and causes it to rise.
300
A composite volcano is different than other volcanoes because it...
Composite volcanoes produce both quiet and explosive eruptions, often alternating over time.
300
Describe how a caldera is formed:
When the top of a composite volcano explodes, the empty space is partially filled with magma that then cools and collapses in on the magma chamber, creating a bowl like shape.
300
What kind of eruption produces pumice, and how does it form?
Pumice comes out of explosive eruptions when water mixes with magma and then evaporates, leaving tiny empty holes.
400
Describe how a volcano forms at a divergent boundary:
A divergent, or spreading boundary opens up a crack in the crust at a mid-ocean ridge where magma rises through the crust.
400
If a volcano has magma that is high in silica, what kind of eruption is most likely?
Explosive eruptions occur with lava that is high in silica, while if lava is low in silica, the eruption is more likely to be quiet.
400
What comes out when a cinder cone volcano erupts?
Cinder cone volcanoes produce explosive eruptions with tephra such as ash, cinders, and volcanic bombs.
400
When magma and gases exit through the side of a volcano, it creates a __ __ __ __.
vent
400
What is a sign scientists use to predict if a volcano might erupt soon?
Earthquakes can occur before volcanoes due to movement within the mantle. The land around a volcano can also swell and change shape.
500
Which is rarer? A hot spot volcano or an Island Arc volcano. Describe how the rarer type of volcano is formed.
Hot spot volcanoes are rarer and are formed when somehow magma works its way through the crust somewhere on a tectonic plate (not at the boundary) and punches through, like the Islands of Hawaii.
500
How is pahoehoe different than aa?
Pahoehoe flows easily (lower viscosity) and cools in ropelike shapes, while aa is much stickier and has a jagged, rough edge.
500
This type of lava is primarily found in explosive eruptions
Rhyolite
500
This volcano in California was formed by the subduction of the Juan de Fuca plate under the North American Plate.
Mt. Shasta
500
In 79 CE, this Roman town received the hottest and most destructive pyroclastic flow from a massive explosive volcano. What is the name of the town and the volcano?
City State: Herculaneum Volcano: Vesuvius