Plate tectonics - Tsunami - Japan
What event caused a tsunami
Japan earthquake. 11th March 2011 Magnitude 9 earthquake. 5th most powerful earthquake ever. The waves travelled at 200km/h near the coast.
Japan background
MEDC GDP per capita of $34,000 Also well prepared for earthquakes
Nature of event
The epicentre was 70Km off the Japanese coast Magnitude 9, created a huge column of water from the release of stress from the Eurasian plate. Over 1200 aftershocks, many above magnitude . This worsened the damage as it shook the already weakened buildings.
Economic impact
Estimated $34 billion in insurance costs. Further $235 billion in infrastructure damage and loss of productivity. $1 billion in donations from NGOs
Tectonic setting
Pacific plate is subducted beneath the Eurasian plate. Stress builds up in the plates and releases the energy as waves. 30% of the worlds earthquakes occur near Japan Pacific plate moves 9cm a year
Social impacts
People forced to scavenge for food through debris - rotten and contaminated - viewed as shameful. Burial procedures slacked to burial without prior cremation.
Damage caused
130,000 buildings collapsed 700,000 partially damaged. 25 million tonnes of debris
How many casualties were there?
15,800 confirmed dead 26,900 injured 5,800 missing 65% of deaths were over 60
Monitoring of event prior
200 seismographs and 600 intensity meters collect data from across the country. Provided a 20 min tsunami warning, wasn't taken seriously as people are you used to these events so didn't evacuate quickly. Though the warning did save many lives.
Impacts
300 hospitals damaged- slowed response and lack of medicine for other conditions, diabetes 1.5 million homes left without water Areas of Japan sank 10m due to the earthquake.
Flood defences
40% of coastline had 10m high sea walls - though some of the 10 tsunami waves reached 15n high. Size increased as the waves added together.
Response post event
Within 10 days of disaster 452,000 were living in evacuation centres wtb supplies.