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• Volcano


  A complex volcano made up of multiple craters formed by eruptions, where eruptions can transfer from one crater to another
• The Taal Volcano's main crater, the Binintiang Malaki crater, is the most visible and highest part of the volcano
• The Taal Volcano's main crater erupted in 2020, confusing people about the exact location of the eruption
• The figure shows a lightning strike during a Taal Volcano eruption, with the volcano spewing columns of ash
• Effusive eruption


  Lava is flowing out of the volcano
• Explosive or violent eruption


  Magma has been blown to pieces
• Volcanic hazards are phenomena arising from volcanic activity that pose potential threat to people or property in a given area within a given period of time
• Volcanic phenomena


  • Lava flows
  • Ash fall or tephra fall
  • Pyroclastic flows and surges
  • Lahars
  • Volcanic gases
  • Debris avalanche or volcanic landslide
  • Ballistic projectiles
  • Tsunami
• Lava


  Molten rock that has reached the surface of the volcano, as opposed to magma which is the molten rock still inside the volcano
• Lava flows


  • They rarely threaten human life because they usually move slowly (a few centimeters per hour for silicic flow, several kilometers per hour for basaltic flow)
  • They can bury, crush, cover, and burn everything in their path
  • They can melt and burn due to the intense heat
  • They can bury homes and agricultural areas under meters of hardened rock
  • They can block bridges and highways, affecting mobility and accessibility
• Lava domes


  Viscous lava that extrudes extremely slowly, forming dome-like structures
• Collapsing viscous lava domes can trigger dangerous pyroclastic flows
• Ash fall or tephra fall


  Showers of airborne fine to coarse-grained volcanic particles that fall out from the plumes of volcanic eruptions
• Ash fall


  • It can cause poor or low visibility, making driving and roads dangerous
  • It can bury and damage agricultural lands
  • It can clog filters, vents, and human lungs
  • It can suspend fine-grained particles in air and water, damaging industrial machines and nuclear power plants
  • It can carry harmful gases, acids, and salts
  • Burial by tephra can collapse roofs, break power and communication lines, and damage or kill vegetation
• Even less than 2 centimeters of ash can damage critical facilities like hospitals, power plants, and storm sewers
• Pyroclastic flows


  Turbulent mass of ejected fragmented volcanic materials or ash and rocks mixed with hot gases that flow downslope at very high speeds
• Pyroclastic surges


  More dilute or mobile derivatives of pyroclastic flows
• Pyroclastic flows and surges

  • They are highly destructive due to their mass, high temperature, high velocity, and great mobility
  • They can destroy anything in their path by direct impact, burn sites with hot rock debris, and destroy forests, farmlands, and buildings
  • The effects include asphyxiation, burial, incineration, and crushing from impacts
• The only effective mitigation method for pyroclastic flows and surges is evacuation prior to such eruptions from areas likely to be affected
• Lahars


  Rapidly flowing thick mixtures of volcanic sediments from pyroclastic materials and water, usually triggered by intense rainfall
• Lahars


  • They can destroy by direct impact, destroying bridges, roads, and houses
  • They can block tributary streams and form lakes, submerging villages
  • They can bury valleys and communities with debris, leading to long-term flooding problems in downstream communities
• Volcanic gases


  • Water vapor
  • Carbon dioxide
  • Sulfur
  • Hydrogen sulfide
  • Hydrogen chloride
• Volcanic gases


  • They can be lethal to people, animals, and vegetation
  • Sulfur dioxide can lead to acid rain when mixed with oxygen and water
• Debris avalanche or volcanic landslide

  A massive collapse of a volcano, usually triggered by an earthquake or volcanic eruption
• Debris avalanches leave an amphitheater-like feature at the base of volcanoes
• Ballistic projectiles


  Volcanic materials directly ejected from the volcano's vent with force and trajectory
• Ballistic projectiles


  • They endanger life and property by the force of impact of falling fragments, but only occur close to an eruption vent
• Tsunami


  Sea waves or trains generated by sudden displacement of water