Japanese earthquake and Tsunami

Question 1

Earthquake details:

Answer 1

• 9.0 magnitude earthquake with a depth of 30 km
• 129 km from sendai
• 383 km away from Tokyo
• 11th March 2011 at 05:46

Question 2

Tectonic setting:

Answer 2

• 9.0 magnitude earthquake hit the Northeast coast of Honshu from a thrust fault on the Pacific/ North American boundary
• The Pacific plate moves westwards at a rate of 83mm per year and descends beneath Japan into the Japanese trench
• The Japan Trench Subduction Zone is one of the most active fault lines in the world with 9 earthquakes of a magnitude above 7 in the last 40 years
• Since the major earthquake in 2011 there have been over 1000 aftershocks with 80 being with a magnitude greater than 6.0
• The east coast of Japan is very vulnerable to tsunami waves due to the nature of the coastline amplifying the tsunami height - up to 40.5 meters
• The faultline was a megathrust where one plate moved vertically between 5 and 10 meters along the 100 km faultline
• Megathrust earthquakes are rare where there have only been 11 in the last century, 10 of which resulting in tsunamis.

Question 3

Social Impacts:

Answer 3

• 100 people died from the earthquake with an extra 19,000 from the tsunami
• More regulated safety standards for nuclear energy
• The financial cost of rebuilding the area was $18 bn
• Japan’s energy future is very uncertain as the government does not have a long term strategy since fukushima cannot be used
• 138,000 buildings destroyed
• 465,000 people evacuated

Question 4

Economics Impacts:

Answer 4

• Disruptions to rail services staffing people in their offices
• The world bank estimated damages to be at least $235 bn
• Estimated payout from insures between $14.5 - $34.6 bn
• All of Japan’s ports had to close during the disaster while 10% of fishing ports were damaged
• Capacity to produce electricity by 40% as the nuclear reactors closed which also caused a trade deficit as increased amounts of oil were imported
• Bank of Japan offered $183 bn to normalise market conditions
• Nissan profits dropped by 15% due to shortages of parts which were usually sourced from the affected areas

Question 5

Environmental impacts:

Answer 5

-Companies such as Canon, Fujitsu, Honda, Nissan, Panasonic, Sony and others due to them being in the affected areas of the power disaster
-Harmful chemicals were leaked out into the environment including hydrochloric acid, chromium and ammonia
-The tsunami caused large damage to the nuclear reactors at Fukushima which release harmful chemicals into the environment
-When the seawater went far inland, the land salinity and the groundwater quality was affected meaning there was a decrease in agricultural productivity and a problem with the drinking water and for irrigation
-The coastal waterways were fully silted by the tsunami and so will need to be drained in order to become operational again.
-Damage to the urban water supply and sewage networks resulted in cross contamination which could lead to severe health impacts.
-The majority of wildlife impacts were on shorebirds including 110,000 Laysan Albatross chicks that were washed away – representing approximately 22% of chicks born this year – along with an estimated two thousand adult albatross.
-Several beaches were washed away, and freshwater habitats were inundated with saltwater.
The tsunami was beneficial for shallow water fish. (Researchers hypothesized that the dead and decaying material in the sea would result in a huge growth in plankton populations. This hypothesis was later confirmed, when scientists observed massive increases in plankton-feeding fish species, like sardines. Increases in fish populations, coupled with reductions in motorized boats in the area, brought more dolphins to the coastal waters as well.)

Question 6

Protection:

Answer 6

• As a result of the high frequency of Earthquakes in this area of Japan, many management has been put in place to protect the coast from tsunami and earthquakes
• 40% of Japan’s coastline is protected by seawalls of up to 10 meters high - however the tsunami was of a greater height than this and thus they were not protected

Question 7

Preparation:

Answer 7

-The Japanese Meteorological Agency (JMA)