tohuku tsunami

Question 1

1. what was the cause of the earthquake?

Answer 1

the radioactive decay in the core causing the hot magma to flow in convection currents which causes movements of the tectonic plates.

Question 2

1. what do the convection currents cause

Answer 2

a subduction zone

Question 3

1. what is a subduction zone

Answer 3

converging of moving plates towards eachother, forming a convergent plate boundary.

Question 4

1. what did the pacific plate do?

Answer 4

submerged under the Eurasian plate and Japan

Question 5

1. what did the subducting plates cause

Answer 5

one of the most powerful earthquakes

Question 6

1. where is Japan situated

Answer 6

along the pacific ring of fire, sitting upon 3 different tectonic plates; pacific, eurasian, Philippine

Question 7

1. what is position is Japan in and what are they extremely prone to

Answer 7

vulnerable position

disaster

Question 8

1. what did the earthquake rupture do to the seafloor

Answer 8

pushed the seafloor upwards with S waves which was a seismic wave on the Pacific Ocean floor as the water became displaced above which resulted in the tsunami

Question 9

1. what happened 20 minutes after the earthquake

Answer 9

the tsunami waves were as tall as 40 meters, struck the coasts if the Iwate prefecture, and one hour later hit Fukushima, Ibaraki and Chiba.

Question 10

2. what did humans greatly intensify and create

Answer 10

the impacts

an entirely different issue for Japan to handle with

Question 11

2. what horrible choice did Japan make

Answer 11

the choice of building a nuclear power plant so close to the coast.

Question 12

2. what did the 14 meter tsunami prove to much to be for

Answer 12

the breakwaters couldn’t handle the tsunami and it came overwhelmingly down on Fukushima

Question 13

2. what did the tsunami disable

Answer 13

the emergency power supply and cooling to the 3 reactors, which caused a significant nuclear reaction

Question 14

2. what happened before the tsunami even hit the coast

Answer 14

the systems at the nuclear power plant detected the quake and automatically shut down the nuclear reactors, emergency diesel generators turned on to keep coolant pumping around the cores

Question 15

2. what happened when the emergency power shut down

Answer 15

the 3 cores melted within the first 3 days, which sparked a major disaster

Question 16

2. why did the exclusive zone grow larger

Answer 16

there was leaking radiation from the plant and more than 150 000 people had to evacuate the area

Question 17

2. where did the radioactive material begin leaking into

Answer 17

the atmosphere and Pacific Ocean

Question 18

2. what caused the damage to buildings

Answer 18

several chemical explosions injuring 16 workers and exposing radiation to several workers.

Question 19

2. what could have avoided the the nuclear accident

Answer 19

better planning and consideration of Japan being situated on tectonic plates.

Question 20

2. what else did humans build on their coast

Answer 20

many coastal towns and prefectures which the tsunami proved to be too much for the infrastructure

Question 21

2.how much of the Japanese coastline did the tsunami hit

Answer 21

200 miles

Question 22

2. other than the tsunami damage what else did the earthquake cause

Answer 22

structural damage due to the severe ground motion which continued for such a long duration

Question 23

2. in what accordance were all the damaged buildings were designed in

Answer 23

old building codes which lacked the seismic strength, short column shear failure due to the source wall and the breast wall or the eccentricity of structural elements

Question 24

2. what happened to the buildings that were fitted with appropriate seismic reinforcement

Answer 24

they were mostly free of damage, indicating these seismic reinforcements were effective

Question 25

2. what did the lack of human awareness cause when planning buildings

Answer 25

destruction to building and left many Japanese devastated

Question 26

3. why did Japan have mitigation strategies in place

Answer 26

because they had prior knowledge and were well prepared

Question 27

3. did it prevent the tsunami

Answer 27

no but it lessens the impact and provided them with more time

Question 28

3. why was Japan motivated to develop coastal protection infrastructures

Answer 28

due to previous 1959 typhoon and 1960 earthquake

Question 29

3. what did they do to protect communities

Answer 29

built 10 meter high seawalls along the coast to protect communities that were greatly devastated through the years

Question 30

3. where was the very first breakwater constructed

Answer 30

the mouth of Ofunato Bay in the Iwate prefecture, where the maximum depth of the bay was 36m

Question 31

3. how was the functionality of the breakwater investigated

Answer 31

through numerical analysis and was the first stage of using computer simulations in tsunami science and engineering

Question 32

3. what breakwater is 63m deep and what does it protect

Answer 32

the Kamaishi tsunami breakwater which is designed to protect the densely populated area in Kamaishi city

Question 33

3. was the Kamaishi breakwater able to protect the population

Answer 33

no but it bought them 6 minutes of time before the tsunami penetrated Kamaishi city

Question 34

3. what did the Kamaishi breakwater reduce

Answer 34

the height of the tsunami by 40% and limited the fatalities in the city to 1253

Question 35

3. was Japan considered well prepared

Answer 35

yes

Question 36

3. how were hazard maps determined

Answer 36

by long term evaluation of seismic activities

Question 37

3. what did 30 years of monitoring and measuring seismic activity uncover

Answer 37

Japan’s seismotectonic structure

Question 38

3. what did these hazard maps suggest

Answer 38

that the tohuku region in the pacific plate was moving westward and subducting beneath the northern American plate at the Japan trench

Question 39

3. what was predicted maximum potential earthquake caused by

Answer 39

the thrust faulting at the plate boundary between the Pacific and North American plates as expected

Question 40

3. was the quake larger than expected

Answer 40

yes

Question 41

3. compare the 2004 and 2011 event

Answer 41

the 2004 Sumatra-Andaman Earthquake killed 220 000, while the 2011 Tohuku event caused over 18 000 fatalities

Question 42

3. why was there a striking level of difference between the 2004 and 2011 event

Answer 42

the level of preparedness

Question 43

3. what did the national cabinet office publish in 2004

Answer 43

‘tsunami and storm surge hazard map manual’

Question 44

3. what did the hazard map display

Answer 44

previously flooded areas by past tsunamis and most likely tsunamis to occur in the future

Question 45

3. what have many coastal communities conducted

Answer 45

regular evacuation drills and held workshops to learn which areas are at risk

Question 46

3. what were the people of Sanriku taught

Answer 46

‘tsunami tendenko’ - people should run without taking care of others even family members

Question 47

3. what did tsunami tendenko encourage

Answer 47

individual decisions and taking personal responsibility of survival

Question 48

3. what was one of the functional aspects of hazard maps

Answer 48

inform people that they were at risk, but it did backfire

Question 49

3. why did hazard maps backfire

Answer 49

they failed to offer accurate prediction in some areas and may have increased the number of fatalities due to people not evacuating soon enough