Q4 Week 1 Volcanic Disasters

• Tephras


  Fragments produced by a volcanic eruption
• Types of Tephras

  • Ash
  • lapilli
  • volcanic bombs
• Signs of an Impending Volcanic Eruption

  • Increase in frequency/occurrence of volcanic tremors
  • Increased steaming activity
  • Crater Glow
  • Ground swells, ground tilt, ground fissuring
  • Localized landslides
  • Drying up of vegetation
  • Increase in temperature in its crater lake
  • Noticeable variation in the chemical content of spring, crater lakes (presence of carbon dioxide and sulfur dioxide spikes)
  • Drying up of springs/wells
  • New/Reactivated thermal areas (Solfataras)
• Summary: crater lake released approx. 100,000 to 300,000 tons (some sources say 1.6 million tons) of carbon dioxide, killing about 1,700 people and 3,500 livestock via asphyxiation.
• Parameters used to monitor Volcanoes

  • Ground Deformation (any surface changes in the perimeter of the volcano)
  • Seismic Activity (tremors/quakes)
  • Gases (presence of CO₂ and SO₂)
  • Sensory Observations (Visual - presence of steam, Auditory - rumbling sounds, Olfactory - smell of rotten eggs (smell of sulfur), Tactile - ground movement is felt)
• Shield Volcanoes


  Low profile (resembling a warrior's shield), low viscosity lava, described as having a relatively gentle effusive eruptions
• Shield Volcanoes


  • Olympus Mons (located on Mars)
  • Mauna Loa (located in Hawaii)
  • Mauna Kea (located in Hawaii)
• Stratovolcano


  Also known as composite volcano, characterized by having a steep profile, with summit crater, known for its explosive eruptions, high viscosity lava
• Stratovolcanoes


  • Mt. Mayon (located in the Philippines)
  • Augustine Volcano (located in USA)
  • Mt. Fuji (located in Japan)
• Caldera type


  Cauldron-like, forms because of collapse due to emptying of magma chamber
• Caldera type Volcanoes


  • Mt. Kīlauea (located in Hawaii, technically a shield volcano)
  • Mt. Pinatubo (located in the Philippines, technically a stratovolcano)
• Lava Dome


  Mound-shaped protrusion, slow release of lava, while being highly viscous, forms inside a caldera volcano
• Lava Dome Volcanoes


  • Mt. Chaitén (located in Chile)
  • Mt. Novarupta (located in Alaska peninsula)
• Countermeasures against Volcanic disasters

  • Monitoring Levels
  • Preparedness Guides
  • Hazard Maps
• Volcanic bombs


  larger than 64 mm (2.5 inches) in diameter
• Volcanic block


  What term is used for volcanic bombs when they are solid?
• • Ground deformation
  • seismic activity
  • gases
  • sensory observations.


  What are the ground parameters monitored to predict volcanic activity?
• Carbon dioxide (CO₂) and sulfur dioxide (SO₂)


  Name two gases monitored as indicators of volcanic activity.
• 1. shield volcanoes
  2. stratovolcanoes

  Strictly speaking there are only 2 types of volcanoes, what are those?
• lava dome and caldera type


  Name two secondary types of volcanoes
• Lava Dome

  What type of volcano is this?