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24 Cards in this Set
- Front
- Back
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What is a volcano?
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A mountain that forms in the earth's crust when molten material, or magma, reaches the surface. They can form at divergent or convergent boundaries.
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What is magma?
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Molten mixture of rock-forming substances, gases, and ater from the mantle.
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What is lava?
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Lava is magma when it reaches the surface of the earth.
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What is the Ring of Fire?
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A belt of volcanoes that circles the Pacific Ocean that includes the volcanoes along the coasts of North and South America and Japan and the Philippines.
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What is an island arc?
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A string of volcanoes that form islands. These occur along converving boundaries where 2 ocean plates collide.
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What is a hot spot?
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An area where material from deep within the Earth's mantle rises through the crust and melts to form magma. Can be at a plate boundary or in the middle of a plate.
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What is a diverging boundary?
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Where 2 plates move apart. Volcanoes can form here. Mid-ocean ridges form and have a rift valley down the center and lava pours out of the cracks.
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What is a converging boundary?
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Where two plates collide. Through subduction, thbe older denser plate sinks into the mantle and creates a trench. The mantle partially melts and the magma rises up and creates volcanoes.
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What is a magma chamber?
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A pocket beneath the surface where magma collects.
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What is a pipe?
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A ong tube that extends from the Earth's crust up through the top of the volcano. Connects the magma chamber to the Earth's surface.
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What is a vent?
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Area of the volcano where molten rock and gas come out. A vent can be on top or on the side of the volcano.
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What is lava flow?
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Spread of lava as it pours out of the volcano.
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What is a crater?
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A bowl shaped area that may form at the top of a volcano around the central vent.
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What is silica?
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A material found in magma that forms from oxygen and silicon.
LOW SILICA=QUIET ERUPTION HIGH SILICA=EXPLOSIVE ERUPTION |
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What is pyroclastic flow?
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A mixture of hot gases, ash, cinders, and bombs that flow down the sides of a volcano in an EXPLOSIVE ERUPTION.
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What is a dormant volcano?
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A sleeping volcano that may become active in the future.
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What is an extinct volcano?
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A dead volcano that will probably never erupt again.
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What is an active volcano?
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A volcano that is erupting or may erupt in the near future.
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What drives or causes a volcano to erupt?
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The force of the expanding gases inside.
If LOW SILICA MAGMA=QUIET ERUPTION If HIGH SILICA MAGMA=EXPLOSIVE ERUPTION |
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What is a caldera?
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A hole left when the volcano collapses. A lake may form here.
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What is a cinder cone?
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A type of volcano that occurs when ash, cincers, and bombs build up around the vent in a steep cone shaped hill or small mountain. These occur in an EXPLOSIVE ERUPTION.
Example: Paricutin in Mexico |
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What is a composite volcano?
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Tall cone shaped mountains formed when silica content of magma varies. Has layers of lava alternating with layers of ash. Example: Mt. St. Helens; Mount Fuji
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What is a shield volcano?
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A wide, gently sloping mountain that forms when thin layers of lava pour out and harden on top of previous layers. Example: Mauna Loa
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What is a volcanic neck?
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A landform that forms when magma hardens in a volcano's pipe and surrounding rock wears away due to water, ice, or wind.
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