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18 Cards in this Set
- Front
- Back
aerosols
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very tiny liquid droplets or solid particles that can remain suspended in air
SO2 in volcanoes react with water in air to create aerosols |
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caldera
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a big circular depression, after major eruptions; up to thousands of meters across); fairly flat floor; calderas differ from craters: size, shape, and mode of formation
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shield volcanoes
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broad, gentle domes
form from low-viscosity basaltic lava or large pyroclastic sheets |
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stratovolcano
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large and cone shaped
consist of alternating layers of lava and tephra Mt. Fuji |
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tuff
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ash or ash mixed with pea- to plum-sized fragments transformed into coherent rock
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tephra
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unconsolidated deposits of pyroclastic grains, regardless of size, that have erupted from a volcano
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pyroclastic flow
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avalanches of hot ash and small fragments (lapilli)
gravity overcomes the upward force and buoyancy of rising ash column, column collapses |
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magma chamber
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an open space or zone of highly fractured rock that can contain a large quantity of magma
some magma freezes in chamber and becomes intrusive igneous rock some rises to Earth's surface |
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lava
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molten rock that has extruded onto the Earth's surface
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lahar
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wet debris flow (tephra and other volcaniclastic debris mixed with rain water or snow) that can rush down channels at high speeds going far distances
at end it is just large clasts suspended in ashy mud |
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volcanic ash
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during andesitic or rhyolitic eruptions, powerful explosions spray lava into the air, forming droplets that instantly freeze
composed of tiny glass shards |
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active volcanoes
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volcanoes that are erupting, have erupted recently, or are likely to erupt soon
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dormant volcanoes
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volcanoes that have not erupted for 10,000 years but do have the potential to erupt again in the future
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extinct volcanoes
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volcanoes that were active in the past but have shut off entirely and will never erupt in the future
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Ring of Fire
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Subduction zones border more than 60% of the Pacific Ocean, creating a 20,000 km-long chain of volcanoes
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volcano
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an erupting vent through which molten rock reaches the Earth's surface or a mountain built from the products of eruption
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basaltic
andesitic rhyolitic |
mafic
intermediate felsic |
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pyroclastic debris
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all fragmental material
(size: volcanic ash, lapilli, blocks and bombs) |