Volcanic Hazards

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  • Created by: Tomek123
  • Created on: 14-09-20 09:12
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  • Volcanic hazards
    • Lava flows
      • Composite volcanos
        • Aa'aa lava
          • surface of aa lava is exceedingly rough, covered with a layer of partly loose, very irregular fragments commonly called clinkers. Aa lava flows are fed principally by rivers of liquid lava flowing in open channels.
      • Shield volcanos
        • Pahoehoe lava
          • Pahoehoe lava flows are characterized by smooth, gently undulating, or broadly hummocky surfaces. The liquid lava flowing beneath a thin, still-plastic crust drags and wrinkles it into tapestry-like folds and rolls resembling twisted rope
    • Pyroclastic flows
      • Temperatures reach over 1000 degrees celcius
      • Can move at 700 km/h
      • Pyroclastic surges can also move over water if they have enough energy
      • A dense, destructive mass of very hot ash, lava fragments, and gases ejected explosively from a volcano and moving very fast
    • Ash Falls
      • Refers to all explosive eruption products (tephra)
      • This will cause damage to buildings and start fires
      • The dust can affect air travel, visibility and health
      • These can vary from bombs which are larger that 32mm or fine dust which is smaller than 4mm
    • Gas eruptions
      • The mix normally includes water vapour, sulphur dioxide, hydrogen and carbon dioxide
      • It's dangerous because it's colourless and can gather in valleys and not be detected by people
    • Fumaroles and Phreatic eruptions
      • Phreatic eruptions
        • A phreatic eruption occurs when magma heats ground water or surface water. The extreme temperature of the magma (anywhere from 500 to 1,170 °C) causes near-instantaneous evaporation of water to steam, resulting in an explosion of steam, water, ash, rock, and volcanic bombs
      • Fumaroles
        • A fumarole is an opening in a planet's crust which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrogen chloride, and hydrogen sulfide.
    • Landslides and dome collapse
      • When lava domes are growth rapidly and becoming unstable they will often collapse and spawn large and deadly pyroclastic density currents and/or massive landslides
    • Volcanic bombs
      • A large rock/boulder which has been ejected from a volcano
    • Lahars
      • A mudflow or debris flow composed of a slurry of pyroclastic material flows down from a volcano, typically along a river valley
    • Jokulhlaup
      • A glacier outburst flood associated with sub-glacial eruptions

Comments

mewaterman

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This is a comprehensive mind map of volcanic hazards, nice one tomek123!

from mewaterman

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