Hazardous Earth - Case Study - Mount Ontake 2014 - Volcano Impacts Flashcards
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, Phillipine)
Why is there intense volcanic activity?
- Widespread subduction
Why do people in Japan chose to live in areas vulnerable to eruptions? (6)
- Japan (AC)- migrants for economic activity
- Tourism- skiing, mountains, economic activity
- Religious relevance- pilgrimage site
- Agriculture- fertile soil (economic activity)
- Densely populated country = people have to move out to live in rural areas = volcanic activity
- 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? (2)
- 63 people killed
- 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?
- Fumes from pyroclastic flows will damage atmosphere- water vapour/carbon dioxide/greenhouse gasses emitted
- Surrounding forest was either destroyed or covered in ash
- Surrounding towns/lodges covered with thick ash
- Pyroclastic flows damaged villages and forests
What were the economic impacts of the 2014 eruption? (5)
- Ski resorts not operational during this time (i.e. Mount Ontake resort closed for 2 months)
- Hundreds of flight, hotel and restaurant reservations were cancelled
- People died and funerals were needed
- Tourist lodges near the disaster either destroyed or covered in ash
- Ash on ground = decline in agricultural output
What were the political impacts of the 2014 eruption? (3)
- Aid/support received from other countries - not able to prepare for an event like this
- Questions as to whether Japanese govt would be prepared for another of these unannounced events
- 2 fault seismometers that the govt supposedly knew about
What was the significance of 2014 eruption?
- Even Japan, with one of most sophisticated monitoring and warning systems in world, could be taken by surprise by the unpredictability of this tectonic hazard
