2011 Japanese tsunami

Question 1

what was the magnitude of the earthquake

Answer 1

9.1

Question 2

what was the date that the earthquake hit

Answer 2

March 11, 2011

Question 3

where did the earthquake hit

Answer 3

off the northwest coast of Honshu on the japan trench.

Question 4

how long did the earthquake last for

Answer 4

6 minutes

Question 5

how long did it take for the tsunami to arrive at the coast

Answer 5

30 minutes

Question 6

how many tsunami occur in the pacific ocean

Answer 6

90%

Question 7

how rare was the 2011 tsunami

Answer 7

a one in a thousand year chance

Question 8

where do most earthquakes occur in relation to japan

Answer 8

eastern part of Hokkaido, as well as the Pacific side of the Kanto region, Tokai region and Kinki and Shikoku regions.

Question 9

what was the spatial impact of the tsunami

Answer 9

561 km2 along the Pacific coast of Japan

Question 10

what is the area around the pacific where earthquakes and tsunami are always occurring

Answer 10

the ring of fire

Question 11

what caused the 2011 tsunami

Answer 11

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.

Question 12

how far did the plant slip

Answer 12

50 metres

Question 13

what did the government call the tsunami

Answer 13

the great east Japan earthquake

Question 14

what were the Environmental impacts

Answer 14

The environmental impacts of the Tohoku earthquake and tsunami include

1. contamination of groundwater (as the saltwater and pollution from the ocean infiltrate the ground due to the tsunami)
2. removal of silt from coastal waterways due to the force of the tsunami
3. 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.

Question 15

what were the economic impacts

Answer 15

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.

Question 16

what were the social impacts

Answer 16

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.

Question 17

how did activities of people intensify the impacts of the hazard

Answer 17

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.

Question 18

explain one type of hazard risk management (tsunami gates)

Answer 18

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

Question 19

explain one type of hazard risk management
(control forest)

Answer 19

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.

Question 20

explain an example of the hazard risk management being used (tsunami gates)

Answer 20

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.

Question 21

explain an example of the hazard risk management being used (control forest)

Answer 21

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.

Question 22

spell the city that implemented tsunami gates

Answer 22

fudai

Question 23

how tall was the tsunami wave at the city that implemented tsunami gates

Answer 23

17 metres

Question 24

spell the town called that implemented control forest

Answer 24

Ishinomaki

Question 25

how tall was the tsunami at Ishinomaki

Answer 25

6 metres

Question 26

what was the prediction of the tsunami

Answer 26

that a 16 m high tsunami would have overrun 600 m in 18 min

Question 27

what was the average velocity of the tsunami

Answer 27

average velocity of 10 m/s.

Question 28

what height can control forest withstand

Answer 28

3-5 metres

Question 29

how long was the tsunami arrive time delayed for

Answer 29

6 minutes

Question 30

what was the tsunami velocity reduced to

Answer 30

2m/s

Question 31

describe p waves

Answer 31

these are a form of body waves and are detected by a seismograph
p wave = primary wave
they travel with a great deal of speed

Question 32

describe S waves

Answer 32

they are a type of body waves
s waves= secondary wave
although s waves are slower they can be more destructive particular in the case of shallow earthquakes

Question 33

descibe love waves

Answer 33

named after the mathematician A.E.H love
they are the fastest surface wave and move the earth side to side in a horizontal movement

Question 34

describe Rayleigh waves

Answer 34

they cause most of the shaking that is felt
the waves move the ground in an up and down and side to side direction and can be much longer than the other waves

Question 35

where was the epicentre of the earthquake located

Answer 35

the earthquake had an epicenter in the Pacific Ocean, 72 km east of the Oshika Peninsula

Question 36

where are convection currents located

Answer 36

in the earths mantle

Question 37

describe what convection currents are

Answer 37

they are heated mantle material that is shown rising from deep inside the mantle, while cooler mantle material sinks, creating a convection current

Question 38

what are convection currents thought to be responsible for

Answer 38

it is thought this type of current is responsible for the movements of the plates of earths crust.

Question 39

what is the name of a sea side town

Answer 39

sendai

Question 40

what was the name of the city that has a nuclear power plant

Answer 40

Fukushima