2011 Japanese tsunami Flashcards
what was the magnitude of the earthquake
9.1
what was the date that the earthquake hit
March 11, 2011
where did the earthquake hit
off the northwest coast of Honshu on the japan trench.
how long did the earthquake last for
6 minutes
how long did it take for the tsunami to arrive at the coast
30 minutes
how many tsunami occur in the pacific ocean
90%
how rare was the 2011 tsunami
a one in a thousand year chance
where do most earthquakes occur in relation to japan
eastern part of Hokkaido, as well as the Pacific side of the Kanto region, Tokai region and Kinki and Shikoku regions.
what was the spatial impact of the tsunami
561 km2 along the Pacific coast of Japan
what is the area around the pacific where earthquakes and tsunami are always occurring
the ring of fire
what caused the 2011 tsunami
The Tohoku earthquake and tsunami were caused by centuries of build-up stress that was released in the convergent tectonic plate margin between the Pacific and the Eurasian plates. This is a common cause of earthquakes as the Pacific tectonic plate is being subducted below the Eurasian plate.
how far did the plant slip
50 metres
what did the government call the tsunami
the great east Japan earthquake
what were the Environmental impacts
The environmental impacts of the Tohoku earthquake and tsunami include
- contamination of groundwater (as the saltwater and pollution from the ocean infiltrate the ground due to the tsunami)
- removal of silt from coastal waterways due to the force of the tsunami
- and destruction of coastal ecosystems.
Further indirect impacts include the environmental toll of reconstruction. The earthquake also caused some beachfronts to drop by 0.5m, generating landfalls in the coastal areas.
what were the economic impacts
The economic impact of the earthquake and tsunami has been estimated to cost £159 billion, the most expensive disaster to date.
The earthquake and tsunami destroyed most of the infrastructure (ports, factories, businesses, and transportation systems) in the worst affected areas and they had to implement a ten-year recovery plan.
Moreover, 1046 buildings in Tokyo were damaged due to liquefaction (the loss of strength in soil due to the movement of earthquakes). The tsunami caused three nuclear power meltdowns, which have caused long-term challenges for recovery as high levels of radiation remain. TEPCO, the Tokyo Electric Power Company, announced that a full recovery of the plants can take 30 to 40 years. Finally, the Japanese government monitors food safety to ensure that they are within the safe limits of radiation content.
what were the social impacts
The social impacts of the earthquake and tsunami include:
• 15,899 people dead.
• 2527 missing and now presumed dead.
• 6157 injured.
• 450,000 lost their homes.
The unfortunate events caused other long-term consequences:
• 50,000 people were still living in temporary homes by 2017.
• 2083 children of all ages lost their parents.
how did activities of people intensify the impacts of the hazard
towns that were low lining in relation to sea level and had large amounts of agriculture and farming-based property, meaning that the landscape was very flat and had no natural protection in terms of trees, bushes, mangroves, and other natural features that act as barricades.
The Fukushima nuclear power plant was built right on the edge of the ocean, this put it in danger of tsunamis and other natural hazards. Therefore, when a 9.1 magnitude earthquake struck Japan, it caused a 15-meter tsunami as well. The water overwhelmed the defensive sea wall, flooding the plant and knocking out the emergency generators. This disabled the power supply and the cooling of three Fukushima Daiichi reactors, causing a nuclear accident beginning on 11 March 2011.
Authorities set up an exclusion zone which grew larger and larger as radiation leaked from the plant, forcing more than 150,000 people to evacuate from the area. There were no deaths immediately during the nuclear disaster. At least 16 workers were injured in the explosions, while dozens more were exposed to radiation as they worked to cool the reactors and stabilise the plant.
explain one type of hazard risk management (tsunami gates)
The use of tsunami gates can be seen to be a very effective way to prevent the effects of a tsunami.
The basic idea behind using Tsunami gates is that you can have the gate opening during the normal time, and then, when need be, you are able to shut it which will block the water out. Tsunami gates can therefore extremely be useful for tsunamis that don’t have a high height as they will be able to completely block out this water.
However, once the tsunami gets too big then the water behind the tsunami gets more powerful and tsunami gates are unable to stop it.
Another important issue raised by the 2011 tsunami is that many firemen were lost in the call of duty as they closed many tsunami gates and the gates of seawalls
explain one type of hazard risk management
(control forest)
A control forest is a popular method that is used all around the world to try and limit the amount of damage that a tsunami causes.
The role of the control forest is to provide coastal protection against the actions of waves, wind, and water currents in general.
The extent to which a controlled forest contributes to saving lives against large tsunamis depends on several factors including the height and velocity of the tsunami, the topography and orientation of the coastline, the width of the forest, and - to a lesser extent - the height, density, and species composition of the forest.
A control forest can be made from many sorts of plants, but mangroves often seem to work the best. The use of a controlled forest has both positives and negatives and is clear that with more work and planning the use of a controlled forest can be a great countermeasure for the future.
explain an example of the hazard risk management being used (tsunami gates)
For example, we can see just how useful this tsunami countermeasure was in the 2011 tsunami.
Fudai used tsunami gates and the results were extremely positive. The water at Fudai was around 17 m and flowed over the gate but only went a few hundred meters past the gate. Most of Fudai village, including the evacuation shelters (primary and secondary schools), were protected, and no loss of human life was reported.
If there had not been a tsunami gate, the tsunami would have damaged the center of the village and caused a huge amount of damage to the town.
explain an example of the hazard risk management being used (control forest)
The control forest in Ishinomaki did a good job of preventing large amounts of harm to the city. All the trees in Ishinomaki survived.
The forest reduced the destructive power of the tsunami and trapped debris, for example, cars, from the water before it entered the city. The trees may have been saved because the height of the tsunami at Ishinomaki was lower (6 m. Without control forests, it is predicted that a 16 m high tsunami would have overrun 600 m in 18 min with an average velocity of 10 m/s.
However, with the control forest, the tsunami arrival time was delayed by 6 min, and its velocity was reduced to 2 m/s. from this, it is clear that control forests work but in general, control forests can withstand tsunamis up to 3–5 m high.
spell the city that implemented tsunami gates
fudai
how tall was the tsunami wave at the city that implemented tsunami gates
17 metres
spell the town called that implemented control forest
Ishinomaki
