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23 Cards in this Set
- Front
- Back
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________________ is the process by which magma from the earth's interior rises, emerges from the surface as lava and cools as volcanic rock. |
Volcanism |
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_______________ is magma that has reached the surface. It generally flows well. |
Lava |
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Volcanism produces threes materials: ________________, __________ and ___________. |
Lava, pyroclastic material and gases. |
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Pyroclastic material is composed mostly of ____ and cinders. |
ash |
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Eruption styles are related to magma __________, which is mostly a function of lava composition. |
viscosity |
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__________ magma is basaltic, flows easily and does not produce explosive eruptions. |
Mafic |
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___________ magma is composed of rhyolites, dacites and andesites. It is very viscous, contains volatiles and produces violent eruptions. |
Felsic |
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Do explosive eruptions produce more or less pyroclastic material? |
More |
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The two controls on the explosivity of an eruption are _____________ and ____________. |
Silica content and gas content. |
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Rhyolite has a _________ Si content and can contain large gas volumes. It leads to more felsic magma and violent eruptions. |
high |
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Basalt has a _________ Si content and cannot contain much gas. It leads to mafic magma and quiet eruptions. |
low |
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There are 6 main volcano types. These are: ____________, _____________, _____________, ______________, _____________ and _____________. |
Shield, cinder cone, composite cone (stratovolcano), fissure eruptions, lava domes and calderas. |
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____________ volcanoes are the largest type and have a fluid mafic magma reservoir. |
Shield |
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________________ volanoes form due to gas buildup and are constructed fully of pyroclasts with no lava flow. |
Cinder Cone |
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_______________________ volcanoes have large, symmetric structures and produce gas-rich magma that is generally more viscous. |
Composite Cone (stratovolcano) |
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___________ ____________ volcanoes are due to long, narrow cracks that extrude mafic material with low viscosity. They can lead to lava plateaus |
Fissure Eruption |
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__________ __________ volcanoes produce high-viscosity magma that often accumulates, forming a Si-rich dome. |
Lava Dome |
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________________ volcanoes are large collapse depressions following eruptions or drainage. |
Caldera |
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Volcanoes are most commonly found at _______________, such as mid-ocean ridges and rift zones, at ____________________, such as Japan, or as_________________ volcanoes, such as Hawaii. |
Spreading Zones, Convergence Zones, Intraplate |
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To be considered active, a volcano must have had an eruption in the last ________________ years. |
10, 000 |
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A _____________ volcano must have an active magma chamber. |
Dorman |
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An extinct volcano does not have an active magma chamber and has not had an eruption in the last ______________ years. |
10, 000 |
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Signs of an impending eruption include: ___________, ____________, _____________ and _____________. |
pH change, seismic monitoring, change in gas composition, change in heat flow. |
