Volcanic Hazards

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Local Hazards
Pyroclastic Flow, Lava Flow, Volcanic Landslides
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Pyroclastic Flow
Occur with explosive eruptions of molten or solid tephra moving down the sides of the volcano or from the collapse of part of a volcanic cone or lava flow. Speed is dependent upon the density of the current, volcanic output rate & gradient of slope
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Lava Flow
Streams of molten rock that pour from an erupting vent. Distance they travel dependent on temp of flow (550-1400 degrees), silica content, extrusion rate & slope of the land.
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Volcanic Landslides
Large masses of wet or dry rocks & soil that fall, slide, or flow very rapidly under the force of gravity. Originate as massive rock falls or avalanches, which disintegrate during movement into fragments
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Regional Hazards- Water Based
Lahar, Jokulhlaups
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Lahar
Hot or cold mixture of water & rock fragments that flows down slopes of a volcano & typically enters a river valley. Small but grow in volume as entrains anything in its path. Caused via heavy rainfall, emptying a crater lake or melting of snow
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Jokulhlaups
Glacial outburst floods which occur with discharge of large volumes of water, ice & debris. Tend to be located anywhere where water accumulates in a subglacial lake beneath a glacier
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International Hazards- Airborne
Toxic Gases, Ash Falls
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Toxic Gases
Significant amounts of CO2, sulfur dioxide, hydrogen sulfide & halides can be emitted from volcanoes. Depending on conc.=hazardous to all surroundings
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Ash Falls
Produced in explosive eruptions (small particles less than 0.1mm can stay in atmosphere for 2-3yrs). Distance ash travels dependent on height of eruption column, air temp, wind direction & speeds
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Other cards in this set

Card 2

Front

Occur with explosive eruptions of molten or solid tephra moving down the sides of the volcano or from the collapse of part of a volcanic cone or lava flow. Speed is dependent upon the density of the current, volcanic output rate & gradient of slope

Back

Pyroclastic Flow

Card 3

Front

Streams of molten rock that pour from an erupting vent. Distance they travel dependent on temp of flow (550-1400 degrees), silica content, extrusion rate & slope of the land.

Back

Preview of the back of card 3

Card 4

Front

Large masses of wet or dry rocks & soil that fall, slide, or flow very rapidly under the force of gravity. Originate as massive rock falls or avalanches, which disintegrate during movement into fragments

Back

Preview of the back of card 4

Card 5

Front

Lahar, Jokulhlaups

Back

Preview of the back of card 5
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