Japanese Tsunami Flashcards
When did the Japanese tsunami occur ?
Match 11 2011
Where did the earthquake that triggered the tsunami occur ?
Off the north east coast of Japan in Pacific Ocean.
Which city was worst affected ?
Sendai
Why did earthquake occur?
Because Japan lies between the Eurasian plate and Pacific plate
2 plates moving towards each other at destructive PB
Form of prediction as most earthquakes occur here
Eurasian …
Continental
Pacific …
Oceanic
What happens when Eurasian and Pacific plate meet?
They meet in Benioff zone in mantle.
Large build up of energy and tension due to friction of plates
Eventually released as EQ
How did the tsunami occur ?
As the earthquake happened the water on the ocean floor was displaced by movement of plate upwards.
Seabed lifted as a result and water on top has to find somewhere else to go so it forms giant wave.
Displaced water forms tsunami
What are waves like over the ocean ?
Small .
Rising only few cm.
Not noticed by passing boats.
Hard to see / predict
What’s the most obvious sign a tsunami is going to occur ?
Costal water retreats before the waves reach the shore.
Prediction
What happens when the waves teach shallower water?
Height increases.
Shallow water slows wave.
Waves get closer
Primary social effect
15,000 died
Homes destroyed.
Power/ gas / water likes disrupted.
Telephone connection cut off
Primary economic
Trains swept off tracks.
Air ports covered in mud.
Large towns were more than 1/3 submerged by waters and debris
Primary environmental
Dam burst it’s banks
Farmland destroyed
Secondary social
215,000 people living in government shelter.
Destruction to road/ rail made it hard for rescue teams.
4 million without power
1 million without water
Radiation exposure
Secondary economic
Oil refineries set on fire impact on fuel supplies.
Total loss $185 billion
secondary Environmental
Fires spread
Radiation leaks from nuclear plant in north Tokyo
Responses to tsunami
Warning system - 5 mins after EQ they issued tsunami warning.
People escaped to higher ground but short like to do so ( 20 mins )
1000s couldn’t escape
Japan has tight building regulations so in Tokyo no buildings collapsed
How much did fudais sea wall cost?
£20 million.
Spanned 673 feet and 50 feet high
Why was fudai implemented?
Because former Japanese mayor made it priority to save the town who lived through earlier tsunami
Town of Taro.
They have a double layer sea wall spanning 1.6 miles but wasn’t as effective as Fudai
Was fudai’s sea wall overall successful ?
No homes swept away or people died in area.
But some water did flow in - the port was badly damaged.
What acts as natural barrier in fudai ?
2 mountainsides flanking the gate
Natural barrier
What happened to fudais port ?
Destroyed boats / equipment and warehouses
3.8 billion yen
Technology and tsunami
Skype provides free calls and free access to internet.
Midi app advised people where o get food and water.
Google set up person finder.
Honda used GPS to calculate which roads were working
