Japan - Tohoku Earthquake Flashcards
Tectonic Setting
- Four tectonic plates meet, release vast amounts of seismic energy
- Movements along plate boundaries lying just offshore of the Japanese mainland create ever-present risk of tsunamis
- Pacific coast especially vulnerable, is densely populated and contains three huge conurbations: Tokyo (36 million), Osaka (19 million), Nagoya (9 million)
Features of Earthquake
- 9.0 Mw
- Largest recorded earthquake to have struck Japan, recording began in 1900
- Epicentre was 70km east of Oshawa peninsula, focus was approximately 30km away
- Honshu island moved 2.4m east
- Earth shifted in axis by 10-25cm
- Very large tsunamis triggered, reaching heights of up to 40.5m in places when hitting coast, travelled up to 10km inland in places
- Tsunami waves of up to 2.4m affected the coastline of California and Oregon, causing damage of US$10 million
- Many more aftershocks, some of which were 7.0-8.0 Mw in strength
Social Impacts
- 16,000 deaths
- 6000 injured
- 2/3 of victims over 60
- Children separated from families, Save the Children reported that 100,000 children were affected - problem made worse as most children were stuck at school when earthquake struck
- 2000 young people either orphaned or lost one of their parents
- Destruction of infrastructure (eg, housing, schools, healthcare centres) on such a scale that reconstruction was still taking place 5 years following disaster
Economic Impacts
- Cost of earthquake, including reconstruction has been estimated at around £181 billion
- 45,700 buildings destroyed, further 143,000 damaged
- 230,000 vehicles destroyed or damaged
- 15 ports directly affected
- 4.4 million households and thousands of businesses lost electricity
Environmental Impacts
- Fukushima Daiichi nuclear power plant, all six reactors were so severely damaged by the tsunami that the power plant was decommissioned
- Plant’s cooling systems were disabled by sea water flooding, which led to a meltdown of reactor cores and the release of radioactivity
- 30km evacuation zone was established around the plant and soils int he surrounding countryside were contaminated by radiation
- Even today, radioactivity continues to seep into the Pacific Ocean, affecting the fishing industry
- Farmland flooded by seawaters has been contaminated by salt and made uncultivable
Political Impacts
- Japanese government injected billions of yen into the economy, especially the financial sector, to bring some stability
- Increased government debt at a time when its reduction was a prime political aim
- Large popular movement against nuclear power developed after earthquake
- Concerns over safety standards and regulation of the nuclear industry became a political issue
- Government has yet to make a clear decision about role of nuclear power in Japan’s long term energy mix
Modifying Vulnerability
Research and Monitoring: Japan Meteorological Agency is responsible for providing information and warnings of impending earthquakes and tsunamis, its detailed disaster planning involves a wide range of organisations (eg. governments, medical services, military, telecommunications companies)
Buildings with aseismic design: Steel frames and braces capable of moving without collapsing, rubber shock absorbers in foundations, a ‘soft storey’ at the bottom of tall buildings such as a car park, which collapses, allowing upper floors to sink down onto it
Fire proofing older wooden buildings which are common in old districts of Japanese cities
Land use zoning that provides for open spaces where people can assemble after earthquakes
Controlling building in locations susceptible to excessive ground shaking or liquefaction
Tsunami warning systems off the coast
Community prepardness - ongoing education and training for all ages
Modifying Loss
One of most advanced countries in the world
Vast resources to manage losses caused by earthquakes
Well rehearsed recovery and reconstruction plans at national, regional and local levels, can be actioned immediately following an earthquake
Aim is to rebuild physically, economically and socially as quickly as possible
