Link to GCSE syllabus: A case study of a tsunami – its cause, effects and responses.
Case Study: The Tohoku Tsunami, Japan 2011
On the 11th March 2011 a powerful earthquake measuring 9.0 on the Richter scale occurred around 100km east of Sendai on Honshu, Japan, In just 30 minutes a wall of water up to 40m high hit the coast of north western Japan. It was followed in places by up to 9 additional waves up to 10m in height. 3000km of coastline was affected by the waves, which tore through coastal defences.
Causes of a tsunami (BBC bitesize)
The earthquake that triggered the tsunami occurred at a destructive plate boundary where the Pacific plate was being subducted (pushed under)the North American plate. A segment of rock around 200km long slipped suddenly and flicked upwards by around 5-10m. This sudden uplift displaced (pushed up) the water creating the tsunami.
- 200000 people killed
- 500km2 coastal plains hit, destroying farmland, settlements and communications.
- Ruptured gas pipes led to fires.
- Explosions at the Fukushima nuclear power plant- this led to nuclear contamination and the possibility of meltdown as the cooling systems failed.
- Electricity lost in 6 million homes, 1 million had no running water,
- Further problems were caused by heavy snow and blocked roads.
- 100,000 Japanese soldiers sent out to search and rescue.
- Specialist search and rescue teams flown in from overseas.
- Exclusion zone set up around Fukushoma, people evacuated from area.
- Longer term: Re-building, re construction. Port facilities rebuilt, tsunami defence system reconsidered and extended.