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| Where are most volcanoes located? |
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Definition
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Definition
| A chain of active volcanoes around the Pacific plate. Most volcanoes occur here. |
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Definition
| This happens when the overlying pressure exerted on hot rock is released. Happens at divergent plate boundaries, continental rifts, and hot spots |
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Term
| Why does the addition of volatiles help magma formation? |
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Definition
| Water and carbon dioxide lowers the melting temp of rocks by breaking chemical bonds |
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Definition
| Resistance to flow in fluids. Greater amounts of silica make it more difficult for magma to flow |
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Definition
| Melted silicate rocks and dissolved gases. |
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Term
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Definition
-Largest volcanoes are shield volcanoes
-Hawaii, Iceland, Indian Ocean
-nonexplosive eruptions due to low viscosity and volatiles |
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Term
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Definition
-Cone shape
-Mt Fuji, Mount St Helens, Mt Ranier
-more viscous, higher volatile content |
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Term
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Definition
| These form within the crater of a volcano. They are highly viscous and highly explosive. |
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Definition
| -builds up near volcanic vent -less than 1000ft tall -common on flanks of large volcanoes, normal faults or cracks & fissures. |
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Term
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Definition
-Mid-ocean ridges and continental rifts
-Subduction Zones
-Hot Spots beneath oceans
-Hot spots beneath continents |
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Term
| Where are composite volcanoes more likely? |
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Definition
Subduction zones
Pacific Rim |
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Term
| Where are Shield volcaoes more likely? |
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Definition
Hot Spots beneath the ocean.
Hawaii |
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Term
| Where are caldera-forming eruptions more likely? |
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Definition
| Hot spots beneath continents |
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Term
| Primary effects of volcanic activity |
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Definition
| Lava flows, ash fall, pyroclastic activity, release of volcanic ash |
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Term
| Secondary effcts of volcanic activity |
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Definition
| debris flows, mudflows, landslides, avalanches, floods, fires and tsunamis |
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Term
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Definition
| produced when magma reaches the surface of earths crust and overflows |
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Term
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Definition
Basaltic
Andesitic
Rhyolitic |
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Definition
| lower viscosity, higher eruptive temps, fastest pahoehoe |
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Definition
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Term
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Definition
| explosive volcanism in which tephra is physically blown from a volcanic vent into the atmoshpere. |
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Term
| Types of pyroclastic activity |
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Definition
Ash fall
Pyroclastic Flows |
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Term
| Gases emitted during eruption |
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Definition
carbon dioxide
carbon monoxide
sulfur dioxide
hydrogen sulfide |
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Term
| Chemical released during eruption that can cause acid rain |
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Definition
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