Production of associated hazards from volcanoes

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  • Created by: alicia8
  • Created on: 13-05-17 15:12
Pyroclastic Flow (primary)
Hot ash&gas moving down side of volcano at 450mph
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Pyroclastic Flow (primary) how is it formed?
If convesction currents arent strong enough in the area the the volcano won't have energy to force out ash into the sky so instead it moves down the side of the volcano
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Pyroclastic Flow (primary) why's it a hazard?
Hard to outrun ash is dense so lands on rooves making buildings collapse and ash also gets into peoples lungs
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Pyroclastic Flow (primary) - case study
Montserrat -1997 5million km3 of ash landed on Plymouth
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Lava flows (primary)
movement of out pouring lava created during a non- explosive effusive erruption
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Lava flows (primary) how is it formed?
If pressure isn't too high lava will run out of the volcano rather than explode out moving quite slowly
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Lava flows (primary) why's it a hazard
V v hot. 700-1200 degrees c. Difficult to control & destroys everything in path.
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Lava flows (primary) - case study
Kalapana, Hawaii - twon totally destroyed in 1990 by lava flow
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Ash/Tephra fall (primary)
volcanic ash consists of tiny jaggered pieces of rock and natural glass blasted into air by volcano. wind carries ash for thousands of miles affecting laaaarge areas of people
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Ash/Tephra fall (primary) how is it formed?
explosive eruptions occur when gasses dissolved in molten rock expand and escape violently into the air. Also when water is heated by magma and abrubtly flashes into steam. force of escaping gas violently shatters rocks creating ash
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Ash/Tephra fall (primary) why's it a hazard?
ash dense = rooves collapse. ash when wet conducts electricity so short circuits electrical items. Ash cloggs up vents&causes breathing problems
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Ash/Tephra fall (primary) - case study
Montserrat 1995 ash travelled for 30 miles covering homes and farm lands
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Toxic Gasses (primary)
Sulphur dioxide, carbon monoxide, methane&neon
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Toxic Gasses (primary) how is it formed
Released from cavities in the volcanic rock or given off when gases mix with heat from magma and lava
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Toxic Gasses (primary) why's it a hazard
Invisible. Get into peoples&livestocks lungs. Burn their insides slowly killing them
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Toxic Gasses (primary) - case study
Iceland 2010 2000g/m3 of toxic gases
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Lahars (secondary)
Mixture of ash debris mud&water running down side of a volcano
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Lahars (secondary) how is it formed?
Hot magma and lava melts ice caps which mixes with ash and debris from the volcano
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Lahars (secondary) why's it a hazard?
Move quickly (22mph) can be up to 140m deep. Once settled become hard. Destroys buildings towns farmlands etc
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Lahars (secondary) - case study
Mount Pinatubo - Tarlac City 6m high lahar killed 1,500 people
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Jokhulaups (secondary)
Ice melted fast flowing river
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Jokhulaups (secondary) how's it formed?
Magma rising through lithosphere heats soil. If there is glaciers on top of soil these melt causing rivers/flooding
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Jokhulaups (secondary) why's it a hazard?
water moves v v quickly with large amounts of energy washing people off their feet&destroying homes. Also, volume of water is large and quite sudden making almost a wave of water
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Jokhulaups (secondary) - case study
Iceland volcano 2010, moving at 2,500m3 a second.
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Volcanic landslide (secondary)
large masses of rock and soil tat fall slide or flow rapidly under force of gravity. Can be v large and move up to 100mph
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Volcanic landslide (secondary) how is it formed?
Each time magma moves toward surface, overlying rocks are shouldered aside as the molten rocks makes room for its self often creating internal shear zones or over steepening one or more sides of the cone
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Volcanic landslide (secondary) why's it a hazard?
Move v v quickly. Unpredictable as doen't have to be when a volcanoes erupting. Destroy everything in path
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Volcanic landslide (secondary) - case study
Mount St Helens May 18th 1980 volume of 2.5km3. Reaching speeds of 50-80m/s
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Card 2

Front

Pyroclastic Flow (primary) how is it formed?

Back

If convesction currents arent strong enough in the area the the volcano won't have energy to force out ash into the sky so instead it moves down the side of the volcano

Card 3

Front

Pyroclastic Flow (primary) why's it a hazard?

Back

Preview of the front of card 3

Card 4

Front

Pyroclastic Flow (primary) - case study

Back

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Card 5

Front

Lava flows (primary)

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