VONA, WOVO, Vog & Laze - Volcanic Eruptions

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Next Week! ! International Court of Justice 📹: Why focusing on this topic? : Volcanic eruptions. Mt. Mayon, Philippines: Active stratovolcano near Legazpi, Part of Albay Biosphere Reserve declared by UNESCO in 2016.

VONA, WOVO, Vog & Laze - Volcanic Eruptions (in English)
Vulcanicity, Volcanoes - Types and 5 Basis for Classification
  • 5.5 million pesos (about $ 100,000) worth of assistance, some in the form of food items for evacuees
  • One of the 22 active volcanoes in Philippines
  • Lahar - mudflow or debris flow

Mount Kusatsu-Shirane, Japan

  • Located in Japan՚s Gunma Prefecture, 93 km away from Tokyo
  • Known for pyroclastic cones and crater lakes (yellow Sulphur on surface)

Mount Agung, Bali

  • Last eruption in 2017 (ongoing)
  • Major eruptions in 1843,1963 - 64 & 2017
  • Large and deep crater
  • Stratovolcano

Mount Kadovar, Papua New Guinea

  • Dormant volcano began erupting only in 2018
  • Currency - Kina
  • Evacuation to Blup Blup island (or Ruprup) & Bam (or Biem)
  • Tsunami warning issued
  • Heightened thermal phenomena was seen in 1976
  • Ash cloud with plume of 7000 ft

All These Discussed Sit on “Pacific Ring of Fire”

Map of Ring of Fire
  • 90 % earthquakes with 75 % of all active volcanoes
  • Result of plate tectonics - 3 boundaries
Plate Tectonics - 5 Elements, 3 Process and 3 Boundaries with Illustrations
  • Hot spots
  • Other events
  1. Peru Earthquake - 7.1 magnitude at 36.3 km depth
  2. Thomas Fire, California - led region vulnerable to mudslide as trees couldn՚t stabilize soil with roots
  3. Mudslides in Montecito, California

WOVO (World Organization of Volcano Observatories)

Organization of and for volcano observatories of the world, volcano surveillance, for warning authorities and the public about hazardous volcanic unrest.

Commission of International Association of Volcanology and Chemistry of the Earth՚s Interior


  • Stimulate communication and cooperation between observatories and institutions directly involved in volcano monitoring
  • Develop and maintain volcano monitoring reference materials, including a Directory of member observatories, their monitoring networks and staff
  • Upon request, to help a member observatory to find temporary scientific reinforcement
  • Refer governments, international organizations, and others seeking assistance in volcano monitoring to the appropriate member observatories.

WOVOdat will be Web-based and open to all with usage for academic research and teaching as well. Headquartered at the new Earth Observatory of Singapore (Nanyang Technological University) .

To help aircraft avoid ash clouds, a universal volcanic alert level system for aviation has been developed as part of the International Airways Volcano Watch, a universal warning system coordinated by International Civil Aviation Organization (ICAO) , a UN specialist agency

Alert-Level Terms

In October 2006, United States Geological Survey (USGS) adopted a nationwide (across US) alert system to characterize unrest and eruptive activity at volcanoes

  • Alaska Volcano Observatory
  • California Volcano Observatory (California and Nevada)
  • Cascades Volcano Observatory (Washington, Oregon and Idaho)
  • Hawaiian Volcano Observatory
  • Yellowstone Volcano Observatory (Montana, Wyoming, Colorado, Utah, New Mexico and Arizona)

Volcano Observatory Notice for Aviation (VONA)

ICAO - use of new structured message to deliver hazard information from volcano observatories

Color codes reflect conditions at or near a volcano and are not intended to pertain to hazards posed downwind by the drifting ash

Aviation Color Codes

Give Prototype Message Format

VONA would be sent (faxed or emailed) by the Volcano Observatory to the pertinent Area Control Centre, Meteorological Watch Office, and Volcanic Ash Advisory Centre.

  • Location
  • Current code
  • Previous code
  • Source
  • Area
  • Summit elevation
  • Remarks
  • Next Notice

VOG (Volcanic Air Pollution)

  • Hazy mixture of SO2 gas and aerosols - composed of sulfuric acid droplets and other sulfate (SO4) compounds
  • Aerosols are created when SO2 and other volcanic gases combine in the atmosphere and interact chemically with oxygen, moisture, dust, and sunlight over periods of minutes to days
  • Particulate matter (PM) , in vog, are characterized as PM2.5 (fine particles) because the particles are less than 2.5 micrometers in diameter-less than 1 ⁄ 20th the width of a human hair.
  • Grow by absorbing water vapor and other gases, so they can increase in size in a moist environment such as the human upper respiratory tract (nose, mouth, and throat) .
  • Far from vent - aerosol are main components
  • Closer to vent - both aerosols and unreacted SO2 gas
  • Case study: Drinking water from 40 % of home catchment systems in the Kona Districts of Hawaii were contaminated with lead leached from roofing and plumbing materials, such as nails, paint, solder, and metal flashings, by acid rain.


  • Localized Air Pollution
  • When molten lava flows into the ocean, it reacts vigorously with sea water to create a different type of gas plume that results in hazy and noxious conditions downwind of an ocean entry.
  • Laze = Lava + Haze
  • Plume = mixture of HCl, Steam, tiny volcanic gas particles
  • Acid rain from plume is corrosive with pH 1.5 to 3.5


  • Volcanic particles that solidify and fall back on the ground

Focus Areas in News (Week 4 - 2018) !

  • Agni 5 Ballistic Missile
  • Pradhan Mantri Surakshit Matritva Abhiyan (PMSMA) Crosses One Crore Mark!
  • Navika Sagar Parikrama INSV Tarini enters port Stanley Falkland Islands
  • International Dam Safety Conference

Forthcoming Lectures

  • Urban Waste Management 📹
  • NDMA Guidelines 📹
VONA, WOVO, Vog & Laze - Volcanic Eruptions (in Hindi)

👌 implies important for Objective Questions/MCQ

📝 implies important for Subjective Questions

📹 implies covered in Videos or Upcoming Videos

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