mount Ontake Flashcards
when did the Ontake eruption occur
27 September 2014
what is japans HDI and GDP
GDP - $4.85 trillion
HDI - 0.909
VEI of the eruption
2-3
what plate boundaries associated with the eruption
on a convergent plate boundary - North American and eurasian plates
what was special about this eruption
it was a phatic eruption - generated by a hydrothermal explosion - more difficult to predict
what was special about the pyroclastic flows
travelled along jigokudani - but there were no burned or fallen trees in the region
what shape volcano Is it
Stratovolcano
2 social impacts of the eruption
250 people trapped on slopes due to pyroclastic flows - no previous warnings - faulty seismometer
63 fatalities
3 economic impacts
18 hectares of farmland destroyed - loss of food security + income for farmers - costs gov to subsidise
ash clouds caused air traffic - planes unable to take off
decrease in tourist activity - less income
2 environmental impacts
water quality affected due to ash in the air
decrease in river ph downstream of Nigorisawa due to lahars
Political impacts
Families of five victims sued the country - seeking 150 million yen - for the failure to raise warning about the eruption
how did they Mitigate the loss
1000 search and rescue workers sent out to search the peaks after the sudden eruption
however 2 days later due to toxic gases such as hydrogen sulphide being released - search team was suspended
how did they mitigate the hazard event
was harder to mitigate the event - as it was explosive - more unpreventable
pheatic eruption is particularly unpredictable as it has a hydrothermal nature
Mount Ontake has only had two known historical eruptions - and previous to 1979 they had not been monitored - therefore scientists had to no data to work with
How did they mitigate the vulnerability (4)
No evacuation even though there were instruments that measure tremors 11 minutes before the eruption
was not until 44 minutes after the eruption that they raised the caution by banning people from entering the area
since the eruption - eco museum has been set up - people can learn about the technology relating to the volcano as well as the disaster management
since the eruption 47 volcanoes have been identified - that are possibly to erupt in next century - now on 24 hour watch - local gov have set up disaster management council
why is having previous data important in mitigating the hazard event
they can predict the type and scale of the eruption - which can save lives - as they can assume which factors will affect people - and therefore creating strategies to minimise risk of certain areas - long term
