Tohoka, Japan 2011

• 11th March 2011 at 2:46pm magnitude 9
• epicentre 24km deep, 80 miles into the pacific ocean
• Pacific plate subducts under Okhelsk plate, 3m of ocean floor displaced
• Ground shaking for 6mins
• 1st tsunami warning 3mins after earthquake for a 10m tsunami
• coast sank 1m lower so could travel further in land
• actual height of tsunami 40m high, travelled 300mph
• 20,000 dead, 14000 missing
• Primary impacts:

  • tsunami destroyed 95% of vegetation
  • transported sediment 5km inland
  • largest breakwaters in the world destroyed- but did reduce some of the damage
  • 65% of victims over 60
  • 300000 buildings destroyed
  • $300bn in damages
  • 4,000 roads, bridges and railways destroyed
• Defences:

  • designed tsunami shelters- but in flooding zone
  • coastal forest designed if artificial breakwater failed
  • largest breakwater in the world
• Secondary Impacts:

  • 20% of 27000 businesses in affected areas not resumed operations as impact on production supply chains
  • Sendai region unemployment of 70% after earthquake
  • rebuilding cost $300bn and caused national debt to rise
• Fukushima:

  • 800,000 evacuated due to contamination
  • radiation in food chain- cattle fed contaminated hay
  • Japan closed all 54 nuclear power plants which supplied 30% of the countries energy, importing fossil fuels added $30bn to the countries energy cost
  • sales of solar cells increase by 30%
• Immediate responses:

  • well-learnt preparedness drills and education did much to save some communities
  • some schools in Kamaishi got 300 kids to high ground
  • Vertical evacuation in Sendai region
• Long-term responses:

  • April 2011 disaster and recovery programme established: ‘compact cities‘ on higher ground; huge coastal levee; provide comprehensive community care facilities
  • February 2012, Reconstruction Agency help rebuild Tohoku to be resilient
  • local government given $25bn for reconstruction
• Why was Japan so vulnerable?

  • protection systems only cope up to 8.0, design features not built to withstand, neither was human response
  • Tsunami walls expected max 4-5m, false sense of security
  • 70% of Japan is mountainous forcing industrial development into coastal areas