Japan Mount Ontake 2014 - Volcano Impacts Case Study

• How many active volcanoes does Japan have?

  110 (several are submarine)
• What % of Japan's landmass is mountainous? What has this been formed by?

  • 70%
  • Volcanic activity millions of years ago
• Why is Japan one of the most tectonically active zones in the world?

  4 tectonic plates meet (North American, Eurasian, Pacific, Philippine)
• Why is there intense volcanic activity?

  Widespread subduction
• Why do people in Japan chose to live in areas vulnerable to eruptions?

  1. Japan (AC) - migrants for economic activity
  2. Tourism - skiing, mountains, economic activity
  3. Religious relevance - pilgrimage site
  4. Agriculture - fertile soil (economic activity)
  5. Densely populated country = people have to move out to live in rural areas = volcanic activity
  6. Geothermal energy
• What is the date of the Mount Ontake eruption?

  27th September 2014
• What is the shape of Mount Ontake?

  Composite/strato volcano
• What is the eruption history of Mount Ontake?

  • Dormant for many centuries until sequence of eruptions (October 1979 - April 1980)
  • Further eruptions followed in 1991 and 2007
• What was the VEI of the 2014 eruption?


  2
• What caused Mount Ontake to erupt in 2014?

  Steam explosion - water inside volcano was superheated; evaporating it into steam = pressure onto surrounding rock surface = exploded (phreatic eruption)
• What is a phreatic eruption?

  Groundwater present - water heated by magma - creation of steam = highly explosive eruption (mainly ash) - no prior warning
• What were the social impacts of the 2014 eruption?

  1. 63 people killed
  2. Large surrounding areas = affected by ash fall, pyroclastic flows, volcanic bombs and lahars = relief struggled to access areas in need of assistance
• What were the environmental impacts of the 2014 eruption?

  1. Fumes from pyroclastic flows will damage atmosphere - water vapour/carbon dioxide/ greenhouse gases emitted
  2. Surrounding forest was either destroyed or covered in ash
  3. Surrounding towns/lodges covered with thick ash
  4. Pyroclastic flows damaged villages and forests
• What were the economic impacts of the 2014 eruption?

  1. Ski resorts not operational during this time (i.e. Mount Ontake resort closed for 2 months)
  2. Hundreds of flight, hotel and restaurant reservations were cancelled
  3. People died and funerals were needed
  4. Tourist lodges near the disaster either destroyed or covered in ash
  5. Ash on ground = decline in agricultural output
• What were the political impacts of the 2014 eruption?

  1. Aid/support received from other countries - not able to prepare for an event like this
  2. Questions as to whether Japanese government would be prepared for another of these unannounced events
  3. 2 fault seismometers that the government supposedly knew about
• What was the significance of the 2014 eruption?

  Even Japan, with one of the most sophisticated monitoring and warning systems in the world, could be taken by surprise by the unpredictability of this tectonic hazard