Kobe Earthquake Case Study Handy Geography

Case Study – Japan Earthquake & Tsunami

(11 March 2011)

About

[Click here to read an independent report]

  • A massive 9.0-magnitude earthquake struck Japan, Friday afternoon, on 11 March 2011 @ 0546 GMT
  • The quake was centred 130 kilometres to the east of the prefecture’s capital, Sendai.
  • A tsunami was sent crashing into the country’s north-eastern coast.
  • It was originally reported at a magnitude of 7.9, but later was upgraded to 8.9 and then to a 9.0.
  • It lasted 6 minutes.
  • That makes it the fifth largest recorded worldwide since 1900, according to the U.S. Geological Service, larger than the 7.9-magnitude Great Kanto Earthquake that devastated Tokyo in 1923 or the 6.8 magnitude quake that hit Kobe in 1995.
  • It had 10,000 times more energy than the magnitude 6.3 earthquake in Christchurch, New Zealand, which struck 17 days earlier

The Cause

  • Japan is located on the east edge of the Eurasian Plate.
  • The oceanic Pacific Plate subducts (sinks under) the Eurasian Plate.
  • This plate margain is “destructive” – it is not a smooth process, friction is present and the plates stick.
  • When the plates stick, tension builds up.
  • When this pressure builds up and is released, it causes a rapid shift in the plates and a lot of energy to be release, in this case about the same as the annual energy output of the UK.

Impact

  • Japan was largely prepared for the earthquake and many buildings remained standing afterwards, but it was not prepared for the subsequent Tsunami.
  • A tsunami warning extended to at least 50 nations and territories, as far away as South America.
  • Damage was caused in Tokyo and many injuries in the north where the quake was centred
  • The yen fell sharply but recouped most of its decline several hours later. Tokyo stocks fell.
  • Local television showed smoke rising from a Tokyo port building, fire in the capital’s waterfront Odaiba district and an oil refinery ablaze in Ichihara, near Tokyo.
  • A tsunami measured at anywhere from one meter to 7.3 meters hit at various places along the coast, while a 10-meter tsunami was seen at the port in Sendai, near the epicentre.
  • Aftershocks were continuing, with one hitting magnitude 7.1, according to the USGS. Tall buildings swayed violently in central Tokyo as the aftershocks hit.
  • Immediate power outages in Tokyo and eight other prefectures reportedly affected some 4 million homes.
  • In Iwate Prefecture a bridge collapsed and a building was washed away, with boats and cars swirling around in the rising waters.
  • In Tokyo, hundreds of concerned office workers tried in vain to make calls on jammed cellphone networks, some wearing hard hats and other protective headgear. Many of them streamed out of buildings in the business district, gathering in open areas. The crowd appeared spooked by the sound of glass windows rattling in tall buildings.
  • Traders said most of the selling was offshore as Tokyo traders evacuated. The yen could be in for further declines as the scale of the damage becomes known.
  • Tokyo’s major airports halted flights, though Haneda Airport was later reported to have reopened several runways. All Tokyo area trains were halted, while the shinkansen bullet train service was suspended.
  • Water could be seen rising over cars and pouring into warehouses at Onahama port in Fukushima Prefecture, with five deaths reported in Fukushima.
  • Two nuclear plants on the Pacific coast in Fukushima were automatically shut down.
  • At Fukushima the subsequent tsunami disabled emergency generators required to cool the reactors.
  • Over the following three weeks there was evidence of a partial nuclear meltdown in units 1, 2 and 3; visible explosions, suspected to be caused by hydrogen gas, in units 1 and 3; a suspected explosion in unit 2, that may have damaged the primary containment vessel; and a possible uncovering of the units 1, 3 and 4 spent fuel pools.
  • Radiation releases caused large evacuations, concern over food and water supplies, and treatment of nuclear workers.
  • The IAEA has rated the events at level 7, the same as Chenobyl, and the highest on the scale – meaning that there is a major release of radio active material with widespread health and environmental effects.
  • The situation has been further compounded by numerous aftershocks.
  • 2,000 people confirmed dead
  • 10,000 more people expected to be confirmed dead
  • 2,000 people injured
  • 530,000 people displaced, staying in 2,500 evacuation centres, such as schools and public halls
  • 24,000 people still completely isolated and cannot be reached
  • 1.2 million homes without power
  • 1.4 million homes without water
  • 4,700 destroyed houses
  • 50,000 damaged houses
  • 582 roads cut off
  • 32 bridges destroyed

Response

  • A Tsunami warning was issued 3 minutes after the earthquake.
  • Prime Minister Naoto Kan, who convened an emergency Cabinet meeting, urged the nation to be calm and said the government will do its utmost to minimize damage from the quake. He told a news conference a large amount of damage had occurred in the northern Tohoku region.
  • A Meteorological Agency official appeared on TV urging those affected by the quake not to return home because of possible tsunamis.
    • “In some areas we have issued a warning of tsunamis of higher than 10 meters and we expect these areas will experience the high water levels soon,” said the official. “Please stay on high alert.”
  • The governor of Miyagi Prefecture asked for Japanese military forces to be sent in to help.
  • The Defence Ministry was sending eight fighter jets to check the damage, the agency said.
  • The government set up a task force at the Prime Minister’s Office. The Bank of Japan set up a disaster control team, headed by BOJ Gov. Masaaki Shirakawa, to assess the impact of the earthquake on financial markets as well as on financial institutions’ business operations.
  • In response, 91 countries have offered aid, from blankets and food to search dogs and military transport.
  • The Japanese government is among the best prepared in the world for disasters and has so far only made specific requests for help, such as calling for search and rescue teams.
  • Several charities, including Save the Children UK, British Red Cross and World Vision UK, are asking for donations.
  • A British rescue team has arrived in Japan to join the search for survivors of the earthquake and tsunami.
  • Fifty-nine search and rescue experts, four medics and two sniffer dogs flew out on a private charter plane with 11 tonnes of equipment on board.
  • Modern innovations, such as Twitter were bringing updates on the situation far earlier than the media.

Links:

BBC – Japan In Pictures

National Geographic – Japan In Pictures

Wikipedia – Japan 2011 Earthquake & Tsunami

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Case studies

Kobe, Japan, 1995 (MEDC)

On 17th January 1995, an earthquake struck Kobe, a heavily populated urban area in Japan. It measured 7.4 on the Richter scale and occurred as a result of plate movement along the boundary between the Philippines Plate, Pacific Plate and Eurasian Plate.

Effects

  • Primary effects happen immediately. Secondary effects usually occur as a result of the primary effects.
Primary effectsSecondary effects

35000 people injured.

Buildings and bridges collapsed despite their earthquake proof design.

Buildings destroyed by fire when the gas mains fractured.

316000 people left homeless and refugees moved into temporary housing.

Responses

These can be divided into short and long term.

Short termLong term

People were evacuated and emergency rations provided.

Rescue teams searched for survivors for 10 days.

Many people moved away from the area permanently.

Jobs were created in the construction industry as part of a rebuilding programme.

Kashmir, Pakistan, 2005 (LEDC)

On 8 October 2005, an earthquake measuring 7.6 on the Richter scale hit the Kashmir region of Pakistan. The earthquake was the result of collision between the Indian and Eurasian plates.

Effects

Primary effectsSecondary effects

Buildings collapsed.

79,000 people were killed.

Landslides, and large cracks appeared in the ground.

Broken sewerage pipes contaminated water supplies and spread disease.

People died of cold during the harsh winter.

Responses

Short termLong term

The army and emergency services arrived to join the rescue effort.

Tents were given out by charities.

Aid workers arrived from abroad to find survivors and treat the injured.

Schools and hospitals were rebuilt.

Building regulations were improved to reduce damage and the death rate in future earthquakes.

Now try a Test Bite.

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