5.4

    Cards (19)

    • Tephra falls
      Volcanic rock and lava materials that are ejected into the air by explosions or carried upward by the eruption column's hot gases or lava fountains
    • Ballistic projectiles
      Rocks that an erupting volcano may hurl into the air, following a projectile path as they are forced out of the vent at steep angles like a cannon ball
    • Tephra falls and ballistic projectiles are both types of volcanic hazards that can occur during explosive volcanic eruptions
    • Tephra
      Volcanic rock and lava materials that are ejected into the air by explosions or carried upward by the eruption column's hot gases or lava fountains
    • Ballistic projectiles

      • They travel like cannonballs and usually land within 2km of the vent
    • Types of tephra falls
      • Ash
      • Lapilli
      • Blocks & Bombs
      • Pele's Tears
      • Pele's Hair
      • Pumice
      • Scoria
    • Ash
      3mm diameter fragment, mix of broken glass and pulverized rock
    • Lapilli
      Size from 2 to 64mm, bigger pumice fragments mixed with finer ash
    • Pele's Tears
      Small pieces of solidified lava drops formed when airborne particles of molten material fuse into tearlike drops of volcanic glass
    • Pele's Hair
      A volcanic glass formation produced from cooled lava stretched into thin strands, usually from lava fountains, lava cascades, or vigorous lava flows
    • Pumice
      A type of extrusive volcanic rock, produced when lava with a very high content of water and gases is discharged from a volcano
    • Scoria
      A dark-colored volcanic rock formed by ejection as a molten blob and cooled in the air to form discrete grains called "clasts"
    • Blocks & Bombs
      Size is 64mm above, bombs are molten when ejected and assume various shapes upon cooling, blocks are large broken pieces of solid vent material or surrounding rocks
    • Dangers of tephra falls and ballistic projectiles
      • Airborne fine particles can harm eyes with conjunctivitis and corneal abrasions
      • Ash accumulation on roofs
      • Ash from distant volcanoes can temporarily isolate small communities and strand people on roadways
      • Ash contains various chemicals, toxic gases, acids, and salts
      • Airborne ash can turn day to night by blocking sunlight
      • Ash clogs many industrial machines and automobiles
    • Mitigating the effects
      Refer to the actions or measures taken to reduce or prevent negative impacts or consequences
    • Mitigating effects before
      • Availability of protective clothing and high efficiency dust masks before volcano-related emergencies
      • Design roof orientation and pitch to discourage thick tephra buildups
      • Strengthen roofs and walls to withstand loading and projectile impacts
      • Wear protective clothing and high-efficiency dust masks
    • Mitigating effects during
      • Patients with lung problems are advised to stay inside their houses to avoid exposure to ash
      • If no approved mask is available, use fabric mask damped with water
      • Keep proper distance between vehicles while driving
      • Clear tephra from roofs as it accumulates
      • Handle the ash in open well-ventilated areas, and wet the dust whenever possible to prevent its movement
    • Mitigating effects after
      • Wear goggles or corrective eyeglasses to protect eyes from irritation caused by fine ash
      • Remove or stabilize tephra on the ground to prohibit reworking
      • Personnel not essential to the emergency should be kept inside and made to strictly observe all safety precautions during cleanup
    • Tephra falls and ballistic projectiles are two types of volcanic hazards that can occur during explosive volcanic eruptions