Japan - Mt Ontake

Question 1

Mt Ontake features

Answer 1

• Strato-volcano situated 200km west of Tokyo on Japan’s largest island, Honshu
• Rises to just over 3000m
• Had been dormant for many centuries until a sequence of eruptions between October 1979 - April 1980, followed in 1991 and 2007
• Area was popular with climbers and trekkers and was a noted tourist destination
• Place of spiritual pilgrimage for many Japanese people

Question 2

Mt Ontake Eruption

Answer 2

• September 2014
• At the time, volcano was not under any alerts or warnings, though some increase in earthquake activity had been observed

Question 3

Impacts of the eruption

Answer 3

• Eruption killed 63 people and large areas surrounding the volcano were affected by ash fall, pyroclastic flows, volcanic bombs and lahars
• Most casualties were climbers and hikers on the slopes of the volcano
• More than 200 survivors made it down the mountain and search and rescue team were deployed to recover those seriously injured
• The Japanese Prime Minister, Shinzo Abe, ordered the military to assist with emergency rescue operations
• For a while, air space in the vicinity of the eruption was closed as a precaution against the possible damaging effects of fine volcanic ash on aircraft jet engines

Question 4

Japan’s tectonic setting

Answer 4

• Located in one of the most tectonically active zones in the world
• Four tectonic plates meet (Eurasian, North American, Philippine and Pacific) and widespread subduction gives rise to intense volcanic activity