Case study of an Earthquake: SENDAI, JAPAN 2011
DEATH TOLL – 15,900
HOMELESS – 230,000
MAGNITUDE – 9.0 on Richter Scale, over 500 aftershocks along the fault
FOCUS DEPTH – 32 km (fairly shallow)
EPICENTRE – Sendai 129km east of epicentre which was out to sea
TYPE OF PLATE MARGIN – Destructive subduction: Pacific Plate subducting under Eurasion plate
TSUNAMI – Japan is used to earthquakes. Buildings & infrastructure better. The tsunami was the deadliest secondary effect as it hit densely populated coastal areas but had a few minutes warning…saved lives
Nuclear accidents= secondary effect
Causes:
- Boundary of 3 different plates
- Destructive (subduction) plate boundary
- Pacific (oceanic, more dense) tectonic plate has been subducting under the Eurasian (continental, less dense) plate for 200 years to the east of Japan
- Process of subduction is not smooth
- Friction causes the Pacific Plate to stick. In the case of Japan pressure built up and on 11th March 2011 this pressure released as an intensely strong earthquake (9.0 on the Richter Scale) and a tsunami with waves of 30m travelling at a colossal speed of 800km/hr which is equivalent to the ground speed of a jumbo jet
- It was followed in places by up to 9 additional waves up to 10m in height.
- 3000km of coastline was affected by the tsunami, which tore through coastal defences
- Nearest city to epicentre was Sendai (130km east of Sendai) and 373km north of Tokyo. First to be hit by Tsunami
- A tsunami warning extended to at least 50 nations and territories, as far away as South America
Impacts:
| Primary | Secondary |
| 15,900 people killed230,000 people homeless from the 10m high tsunami which passed over the defensive sea wall- only 9m high4,700 destroyed houses50,000 damaged houses582 roads cut off32 bridges destroyed4 trains swept away from their tracksA cruise ship carrying 100 people was washed away by the force of the wave1800 homes in the town of Minimosa destroyed and 1/3 of the city of Kensennuma was under waterA dam in the north of Fukushima burst its banks, which caused homes to be swept awayPower lines, gas and water services were severely disrupt red as the earthquake ruptured underground cablesPublic telephone systems knocked out with no signal for mobile phones and internet28 million tonnes of debris500km2 coastal plains hit, destroying farmland, settlements and communications. | 500,000 people forced to live in sheltersThe disruption caused to rail and road links meant that it was hard for rescue teams to reach places where it was neededThe damage to the underground gas pipes led to fires which spread quickly and ignited wood carried by waveAs clean water was scarce, water borne diseases spread quickly such as CholeraThe earthquake caused a power cut at Fukushima Daiichi Nuclear Power Plant which caused a failure in its cooling systems and subsequently caused radioactive materials to escape causing local radioactivity level to increase but up to 40,000 x more than normalJapan lost £90 billion in its shares Total cost to rebuild affected areas was £185 billion4 million homes in and around Tokyo suffered. power cutsFurther problems were caused by heavy snow and blocked roads. |
Response:
| Short Term | Long Term |
| Within minutes of the Tsunami, Japan altered its energy response teams – 300 planes and 40 ships from the militaryAn estimated 100,000 people began the disaster relief missionThe Japanese Red Cross mobilized 230 emergency teams to the worst affected areas to provide medical and moral supportOn the 2nd April, Japan and USA joined forces to search for the bodies along the east coastShelters were set up in schools for those who lived in close proximity to the power plantMany NGOs responded for example Shelter box sent 1,500 boxes of aid within the first month of the disasterThe PM visited each disaster zone by helicopter | In March, Japan’s meteorological agency issued on earthquake warning, followed by a tsunami warningsThis meant that many people were able to escape to higher ground, but the short (20 minutes) meant that thousands could not escapeThe Japanese government responded to this disaster by questioning their huge walls and Tsunami flood gates as they were not efficientMarch 2012 year after 330,00 living in temporary accommodationThe government also responded to this disaster by reviewing their methods on predicting earthquakes and tsunamis and cutting response timesImproving communications and sirens |
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