Earthquake case study - Japanese earthquake and tsunami 🗾

An earthquake occurred off the coast of the island of Honshu on March 11th 2011. It measure approximately 9.0 on the Richter scale and the epicentre was 60km from the coastline. It was a shallow earthquake; 25km deep, and it lasted 4 minutes. It occurred on the convergent plate boundary of the Pacific and Eurasian plates; the Pacific subducts forming a deep ocean trench. Th continental plate rebounded by 5- 8m after being subjected to stress over a 180km stretch, and Honshu moved Eastwards by 2.4km.

The sudden rebound caused a tsunami; a series of large waves up to 100km across and that can travel at speeds of up to 1000km/hr. The Japanese tsunami was between 4m and 10m in height, and surged for several km. Sendai was the first town to be hit; it only got 10 minutes warning. Human error played a huge part in the destruction, authorities completely underestimated its destructive capabilities and so did not warn/evacuate people accordingly. Many who were evacuated did not move far enough as they believed it was only going to be small.

Short term effects

  1. 25,000 dead or missing

  2. Nuclear power plants were shut down eg. Fukushima was shut down as power cuts forced cooling systems to fail.

  3. Widespread power cuts affected domestic and business supplies

  4. Entire towns were wiped off the map; houses destroyed and 200,000 homes effected in total

  5. All infrastructure was destroyed

  6. More than half a million people evacuated

  7. Industry output declined

  8. Food shortages occurred

Long term effects

  1. Cost over €200 billion in damages to date (figures still rising)

  2. Countries have rejected Japanese food imports for fear of radiation contamination.

  3. Fukushima is still leaking today; this is posing problems for the economy and the health of the nation.