Background

• A 9.0 magnitude earthquake struck off Japan’s northeast coast, 250 miles from Tokyo, at a depth of 20 miles on March 11, 2011, at 2:46 pm local time.
• Occurred 250 miles off the northeast coast of Honshu, Japan’s main island.
• The earthquake resulted from the subduction of the Pacific Plate beneath the Eurasian Plate, a destructive plate margin.
• Built-up friction over time led to a massive ‘megathrust’ earthquake.
• Energy release was 600 million times the energy of the Hiroshima nuclear bomb.
• Post-earthquake studies found a thin, slippery clay layer in the subduction zone, which allowed a significant plate displacement of 164 feet and contributed to the massive earthquake and tsunami.
• The combination of the earthquake’s shallow depth and high magnitude generated a devastating tsunami.

Primary Effects

• 15,894 people died, and 26,152 were injured.
• 130,927 displaced, with 2,562 missing.
• 332,395 buildings, 2,126 roads, 56 bridges, and 26 railways damaged or destroyed.
• 300 hospitals damaged, 11 destroyed.
• Over 4.4 million households in northeast Japan were without electricity.
• Significant disruptions to Japan’s transport network.
• Coastal land subsidence by over 50 cm in some areas.
• Due to tectonic shifts, North East Japan moved 2.4 m closer to North America.
• Pacific plate slipped westwards by 20 to 40 m.
• Seabed near the epicentre shifted by 24 m; off Miyagi province by 3 m.
• Earthquake altered Earth’s axis by 10 to 25 cm, shortening the day by 1.8 microseconds.
• Liquefaction damaged 1,046 buildings in Tokyo’s reclaimed land areas.

Secondary Effects

• The earthquake cost was estimated at US$235 billion, making it the most expensive natural disaster in history.
• Tsunami waves up to 40m high caused widespread devastation, killing thousands and causing damage and pollution up to 6 miles inland; only 58% heeded tsunami warnings.
• Fukushima nuclear power station experienced a meltdown in seven reactors; radiation levels spiked to over eight times the norm.
• Transport networks in rural areas were severely disrupted; the tsunami destroyed major roads and railways and derailed trains.
• The ‘Japan Move Forward Committee’ suggested young adults and teenagers could aid in rebuilding efforts.
• Coastal changes included a 250-mile stretch of coastline dropping by 0.6m, allowing the tsunami to travel further inland.

Immediate Responses

• The Japan Meteorological Agency issued tsunami warnings three minutes after the earthquake.
• Scientists had been able to predict where the tsunami would hit after the earthquake using modelling and forecasting technology so that responses could be directed to the appropriate areas.
• Rescue workers and around 100,000 members of the Japan Self-Defence Force were dispatched to help with search and rescue operations within hours of the tsunami hitting the coast.
• Although many search and rescue teams focused on recovering bodies washing up on shore following the tsunami, some people were rescued from under the rubble with the help of sniffer dogs.
• The government declared a 20 km evacuation zone around the Fukushima nuclear power plant to reduce the threat of radiation exposure to local residents.
• Japan received international help from the US military, and search and rescue teams were sent from New Zealand, India, South Korea, China and Australia.
• Access to the affected areas was restricted because many were covered in debris and mud following the tsunami, so it wasn’t easy to provide immediate support in some areas.
• Hundreds of thousands of people who had lost their homes were evacuated to temporary shelters in schools and other public buildings or relocated to other areas.
• Many evacuees came from the exclusion zone surrounding the Fukushima nuclear power plant. After the Fukushima Daiichi nuclear meltdown, those in the area had their radiation levels checked, and their health monitored to ensure they did not receive dangerous exposure to radiation. Many evacuated from the area around the nuclear power plant were given iodine tablets to reduce the risk of radiation poisoning.

Long-term Responses 

• One month post-disaster, Japan established the Reconstruction Policy Council for National Recovery, focusing on tsunami-resilient communities.
• The government allocated 23 trillion yen for a ten-year recovery plan, introducing ‘Special Zones for Reconstruction’ to attract investments in Tohoku.
• Coastal protection policies involving seawalls and breakwaters were adopted to withstand tsunamis with a 150-year recurrence interval.
• Enacted ‘Act on the Development of Tsunami-resilient Communities’ prioritizing human life and promoting infrastructure and defence measures against major tsunamis.
• Post-earthquake, Japan faced economic challenges, with the disaster impacting stock market values and raising concerns about economic recovery.
• Infrastructure repair included 375 km of the Tohoku Expressway and Sendai Airport runway, with significant efforts from the Japanese Defence Force and the US Army.
• Reconstruction efforts also focused on restoring energy, water supply, and telecommunications infrastructure, achieving significant restoration rates by November 2011.