hazards associated with volcanic eruptions

Question 1

lava flows - basic lava

Answer 1

• basaltic lava
• free flowing and travels long distance
• located in Hawaii
  EX - July 2015 - flowed 20km
  
  • August 2015 - flowed 800m in a day

Question 2

lava flows - acidic lava

Answer 2

• containing rhyolite
• thick, not easily flowing
• burned, bulldozed or buried environment
• damage to infrastructure, property and crops
• rarely affects people

Question 3

pyroclastic flows

Answer 3

• 500 degree gases, ash and rock fragments at 100km/h
• follows contours of ground and destroys everything
• inhalation of gas and ash is poisonous, equating to instant death
  EX - Pompeii overwhelmed from Mt Vesuvius in AD 79

Question 4

tephra

Answer 4

• where materials were ejected
• size range of ash, large bombs, pumice
• buries farmland = destroying crops
• transport disrupted on ground and air
  EX - Eyjafialljökull - April 2010 = 100,000 flights cancelled

Question 5

toxic gases

Answer 5

• co, co2 and so2 = deadly

- so2 and rainwater = acid rain and increases weathering and damage crops and pollute surface water and soils

Question 6

lahars

Answer 6

• mud flow - consistency of wet concrete
• snow and ice melt and flow rapidly
• fragments of rocks, ash and soil mix
• travel at 50km/h and destroy all
  1984 Nevada de Ruiz - 23,000 deaths

Question 7

floods

Answer 7

• eruption beneath ice field/ glacier = increasing melting
• water accumulation until exit from under ice = torrent of water = floods
• floods = jökulhalups
  EX Iceland, Vatnajökull ice field

Question 8

tsunamis

Answer 8

-violent eruption on island volcanoes = displacement of ocean water
- waves capable of speeds of 600km/h, height of 1M and wavelength 200km
- at the shore tsunamis waves height and energy transfer along the shore and island
EX - Krakatoa 1883 - 36000 died