CHAPTER 5 VOLCANIC HAZARDS

• Volcano


  A vent or 'chimney' that connects molten rock (magma) from within the Earth's crust to the Earth's surface
• Stages of volcano


  • Active - often erupts
  • Dormant - has not erupted for 2 000 years
  • Extinct - has not erupted for at least 10 000 years
• Types of lava flow

  • Basaltic
  • Andesitic
  • Rhyolitic
• Basaltic lava flow


  • Fastest
  • Low viscosity
• Andesitic lava flow


  • Forms lava domes
  • Comes in small volume
• Rhyolitic lava flow


  • High viscosity
  • Slowest
  • Associated with violent eruptions
• Other types of lava flow

  • Pillow
  • Sheet
• Pillow lava flow


  • Pillow shaped
  • Underwater lava
• Sheet lava flow


  • Thicker surface
  • Associated with violent eruptions
• Volcanic gases


  • CO2- Carbon Dioxide
  • CO- Carbon Monoxide
  • SO2- Sulfur Dioxide
  • H2S- hydrogen sulfide
  • H2SO4- sulfuric acid
  • NH3- ammonia
  • F2- florine
  • HF- hydrogen flouride
  • HCl- hydrochloric acid
• Pyroclastic flow


  A hot mixture of fresh lava, gas, rock, pumice, and ash
• Tephra


  Volcanic rock and lava materials that are ejected to air during an eruption
• Lahar flow


  A mixture of fresh volcanic material and water, formed by heavy rainfall or melted polar ice cap
• SUBDUCTION ZONE - A volcanic formation process that includes the collision between continental plate and oceanic plate
• LAHAR FLOW - A mixture of fresh volcanic material and water, formed by heavy rainfall or melted polar ice cap
• VOLCANIC GASES - Include carbon dioxide, carbon monoxide, sulfuric acid, flourine, hydrogen flouride, ammonia, sulfur dioxide, hydrogen sulfide, and hydrochloric acid
• DORMANT - A stage of volcano that has not erupted for at least 2000 years
• BASALTIC LAVA FLOW - A type of lava flow that is the fastest due to low viscosity
• MAYON VOLCANO - The most active volcano in the Philippines
• RHYOLITIC LAVA FLOW - A special type of lava flow that is associated with violent eruption
• VOLCANO - A "chimney" that connects the magma from within the Earth's crust and surface
• HCl - The chemical formula of hydrogen chloride (hydrochloric acid)
• MAGMA CHAMBER - The reservoir of magma beneath an active volcano