The earthquake was the biggest ever recorded to have stuck Japan, at approximately 9.0. The epicenter approximately 70 kilometres east of the Oshika Peninsula of Tōhoku and the hypocenter or FOCUS at an underwater depth of approximately 32 km (20 mi).
There were 7 foreshocks, including a magnitude 7.2 earthquake on the 9th of March, 2 days before the 8.9-9.0 magnitude earthquake of the 11th. There were also 1235 aftershocks, many at 7 of above and over eight hundred aftershocks of magnitude 4.5 MW or greater . The earthquake also followed Omori’s law, where the number & size of earthquake aftershocks declines with time from the largest event. In addition, 30% of the world’s earthquakes occur close to Japan, so Earthquakes are common, but earthquakes of this size are rare.
The above information shows that Japan is highly vulnerable to Earthquakes, they occur here naturally and in high numbers. The coastline is also vulnerable, as the vast majority of people live on the coast of Japan. This is due to Japan’s physical geography, having a very mountainous spine to the country and only a narrow coastal strip. This exposes high numbers of people to the hazards of tsunami.
The upper 10m of the soil in this zone was also very vulnerable, as the waves amplified in this soil and caused liquefaction.
In this instance it was the Eastern seaboard of Japan and the Island of Honshu that were vulnerable. The Fukushima nuclear power plant also faced directly the epicentre of the Earthquake.
- Capacity to cope (prediction, preparation, prevention)
As a result of the high frequency of Earthquakes in this area Japan has developed a high capacity to cope with both Earthquakes and tsunami.
40% of Japan’s coastline has sea walls of up to 10m high to withstand incoming tsunami waves for example.
Japan has a hazards agency, the Japanese Meteorological Agency, which is set up for the prediction of earthquakes and tsunami. It detected the Earthquake and issued televised warnings just after the very rapid P-waves that arrived but before the more damaging S waves. This gave people a chance to get outside of buildings to safety. It also predicted the tsunami from this event just 3 minutes after the major earthquake, giving people 20 minutes to get to safety. The JMA broke this news on live television, and messages went out on Japan’s mobile network.
Buildings in Japan are also designed to cope with Earthquakes, and Japan’s high level of development means that buildings are made to be life safe and can actually move with earthquake waves and reduce damage.
- Institutional capacity
Japan had its emergency crews and the army on site very quickly after the event. They have readily trained teams of people to go in and assist with events like this
Buildings are earthquake proof and people in Japan are trained YEARLY on the 1st of September in how to survive earthquakes, this is a result of the Tokyo (great Kanto) Earthquake of 1923.
Japan has a huge GDP; it was $34,000 in 2011, which allows it huge leeway ion terms of planning for Earthquakes and tsunami. 40% of Japan’s coastline has sea walls of up to 10m high to withstand incoming tsunami waves for example.
To monitor earthquakes, the Japanese Meteorological Agency operates network of about 200 seismographs and 600 seismic intensity meters. It also collects data from over 3,600 seismic intensity meters managed by local governments and the National Research Institute for Earth Science and Disaster Prevention (NIED). This information is put into the Earthquake Phenomena Observation System (EPOS) at the headquarters in Tokyo
When an earthquake occurs JMA immediately issues to the public, information on its hypocenter, magnitude and observed seismic intensity. This information also plays a vital role as a trigger for the initiation of rescue and relief operations related to earthquake disasters (JMA).
Live footage of the actual earthquake - what impact did JUST the earthquake have?
- Immediate response
Many people got outside during the earthquake and the response to the Earthquake was reasonably good. The warnings from the JMSA also helped save lives. Many people did not react quickly enough to the tsunami alert, and even if they did the 20 minutes or less warning was insufficient for the people to escape.
The JMA and government did a good job of monitoring and getting warning to people, and this probably saved many lives.
Over 340,000 displaced people in the region needed catering for, and issues included shortages of food, water, shelter, medicine and fuel for survivors.
The Japanese government responded by sending in specially trained people such as the Self-Defence Forces, a domestic response.
Many countries such as the UK sent search and rescue teams to help search for survivors. NGOs and other Aid agencies helped too, with the Japanese Red Cross reporting $1 billion in donations.
7. SEE impact (include primary and secondary Hazards)
The Tsunami and Earthquake both had devastating impacts, but the tsunami caused the most damage.
The tsunami waves that reached heights of up to 40 metres in Miyako and which, in the Sendai area of Honshu, travelled up to 10 km (6 mi) inland.
The island of Honshu was moved 2.4 m east and shifted the Earth on its axis by estimates of between 10 cm and 25 cm.
The most worrying impact was on Japan’s famed nuclear power industry. There were several nuclear incidents but the most notable was 3 nuclear meltdowns at the Fukushima power plant. This cause contamination of the sea and land, and force the evacuation of local residents. A brave team of nuclear power plant workers battled bravely to prevent the nuclear reactors overheating completely and exploding.
This resulted in a social impact; residents within a 20 km radius of the Plant were evacuated.
The official death toll report confirmed 15,854 deaths, 26,992 injured and 3,155 people missing across twenty prefectures.
In addition 130,000 buildings totally collapsed and another near 700,000 buildings partially damaged.
The earthquake and tsunami also caused extensive and severe structural damage in north-eastern Japan, including heavy damage to roads and railways as well as fires in many areas, and a dam collapse.
Around 4.4 million households in northeastern Japan were left without electricity and 1.5 million without water.
The economic losses are thought to be huge, given Japan’s highly developed infrastructure and level of development there was a lot to be damaged. The World Bank estimated cost was US$235 billion, making it the most expensive natural disaster in world history.
Estimates of insured losses from the earthquake alone ranged from US$14.5 to $34.6 billion. The Bank of Japan offered 15 trillion Yen (US$183 billion) to the banking system to normalize market conditions.
All of Japan’s ports had to close at least temporarily during the disaster, and 10% of the fishing ports were damaged.
- Long term responses (domestic, international, NGOs)
Interactive – how Japan had recovered one year on.
Just 6 days after the quake a motorway was repaired – this shows the incredible rapidity with which the Japanese can work with their capacity to cope. The BBC also released a series of photographs showing the same areas directly after the tsunami and one year later, the response is incredible.
After a quake hits, children are required to stay in school until an adult comes to collect them, in case their homes are damaged or their family members aren’t available to look after them.
As a result television footage from school and offices in Tokyo during Friday’s quake showed workers and students behaving with extraordinary calm and composure as buildings shook violently, sending files tumbling from desks and books from shelves.
After the quake crocodiles of children could be seen in Tokyo walking calmly to muster points wearing their protective helmets.
Many lessons were learned from the Kobe earthquake of 1995 that killed 6,400 people and forced a reassessment of the building regulations for both residential offices and transport infrastructure.
Damage to buildings in Tokyo was slight as a result of Japan’s stringent building regulations that ensure that skyscrapers sway in during a quake, but don’t collapse.
Buildings are made earthquake proof with the aid of deep foundation and massive shock absorbers that dampen seismic energy. Another method allows the base of a building to move semi-independently to its superstructure, reducing the shaking caused by a quake.
Photographs from the Kobe earthquake showed old buildings collapsed alongside modern buildings that withstood the quake, in some cases canted at an angle, but still standing, after the ground beneath them liquefied.
Immediately after an earthquake strikes in Japan, all television and radio stations switch immediately to official earthquake coverage which informs the public of risks, including tsunamis to enable people to retreat to higher ground or, on the coast, purpose-built tsunami defence bunkers.
For those trapped, all offices and many private houses in Japan have an earthquake emergency kits, including dry rations, drinking water, basic medical supplies. Offices and school also keep hard-hats and gloves for use in the event of a quake.