On Friday, March 11, 2011 at 2.46 PM, an earthquake of magnitude 9.0 on the Richter scale occurred. It was at the point where the Pacific tectonic plate slides beneath the North American plate. The epicentre was 30 kilometres below the Pacific Ocean sea bed and 129 kilometres off the east coast of Honshu, Japan. This triggered a tsunami. Waves were generated and travelled across the Pacific Ocean. The area worst affected by the tsunami was the east coast of Honshu in Japan.
The wave travelled as far as 10 km inland in Sendai.
The tsunami flooded an area of approximately 561 km2.
The waves destroyed protective tsunami seawalls at several locations.
The massive surge destroyed three-storey buildings where people had gathered for safety.
A state of emergency was declared at the Fukushima nuclear power plant, where a cooling system failed and released radioactive materials into the environment.
In July 2013, TEPCO, the Tokyo Electric Power Company, admitted that about 300 tons of radioactive water continued to leak from the plant every day into the Pacific Ocean.
Social and economic
Four years after the earthquake, around 230,000 people who lost their homes were still living in temporary housing.
The total damages from the earthquake and tsunami are estimated at 300 billion dollars (about 25 trillion yen), according to the Japanese government.
The number of confirmed deaths as of April 10, 2015 is 15,891. Most people died by drowning. More than 2,500 people are still reported missing.
Responses to the disaster
The country recently unveiled a newly-installed, upgraded tsunami warning system.
Earthquake engineers examined the damage, looking for ways to construct buildings which are more resistant to quakes and tsunamis. Studies are ongoing.