Volcanic Eruptions and Hazards

• The reading material covers Earth Science related to volcanic hazards, signs of impending eruptions, interpreting hazard maps, and safety measures before, during, and after an eruption.
• The AUF Honor Code implores honesty, integrity, scholarly standards, proper citation, and appropriate data use.

Volcanic-Related Hazards

• Lahar: A wet cement-like mixture of volcanic material and water, often incorporating older volcanic materials from rivers; known for its high mobility and potential to manifest as large boulders.
• Ashfall (Tephra Falls): Consists of fragmented volcanic particles less than 2mm in diameter.
• Pyroclastic Flows: A dense current that moves slower than a surge, while a pyroclastic surge is a diluted type with more mobility. Pyroclastic Density Currents (PDC) release materials from the volcano's mouth after its explosion.
• Ballistic Projectiles: Projectiles that may be likened to a cannonball, with a range of 2-5 km from the vent.
• Volcanic Gases: Variety of gases released from eruption, including;
  • Water Vapor: Colorless, odorless, harmless and most abundant.
  • Carbon Dioxide: Colorless, odorless, and may cause unconsciousness and death in exceeding 15% concentration.
  • Sulfur Dioxide: Colorless with pungent odor and may create smog.
  • Hydrogen Sulfide: Colorless, flammable gas with strong offensive odor.
  • Hydrogen Halides: Toxic acids that quickly dissolve in the atmosphere and become components of acid rain; poisonous.
• Lava Flows: Rivers of incandescent molten rocks flowing from an eruption vent, varying in speed based on silica content; low silica magma results in low viscosity and high-speed flow, while high silica magma leads to high viscosity and slow movement.

Signs of an Impending Volcanic Eruption

• Increased frequency and intensity of earthquakes.
• Increased release of steam and gases from vents.
• Increased fumarolic activity and heat emission.
• Visible ground elevation changes and fissuring.
• Visible flowing lava with red-orange colors at the volcano's mouth.
• Landslides.
• Drying up of springs or bodies of water in the area.

Interpretation of Volcanic-Hazard Maps

• Hazard Maps serve as a guide indicating danger and safe zones near a volcano.
• A country's risk assessment for volcanic eruption is based on volcano activity and population density.

Preparing for an Eruption

• Continuously monitor volcanic activity. Immediately evacuate when a warning is issued that requires leaving danger zones
• Develop a family evacuation plan compliant with community guidelines.
• Prepare transportation, communication, food, water, medicines, and survival kits.
• Review educational materials and adhere to advisories on volcanic hazards, including earthquakes, tsunamis, and flooding.
• Fireproof premises by removing flammable materials.
• Engage in community efforts to mitigate volcanic hazard effects.

What to do During an Eruption

• Evacuate carefully and orderly to designated evacuation centers.
• Stay inside evacuation centers once there
• Keep doors and windows closed to avoid ash exposure
• Use a gas mask to protect eyes and the respiratory system from ash.
• Stay alert for advisories on volcanic activity status and potential re-evacuation to safer sites.

Safety Measures Post-Eruption

• Remain in place and avoid returning to danger zones unless authorities deem it safe.
• Send only adults to check the safety of affected areas.
• Proceed with caution when re-entering areas.
• Contribute to community efforts by ensuring availability of safe food, shelter, water, sanitation, medicine, and other necessities.
• Help maintain peace, order, and cleanliness within the evacuation center.