The 2011 earthquake off the coast of Japan was a magnitude 9.0 (Mw) undersea megathrust earthquake that occurred on 11 March 2011.
It was the most powerful known earthquake ever to have hit Japan, and the fifth most powerful earthquake in the world since modern record-keeping began in 1900.
The earthquake triggered powerful tsunami waves that reached heights of up to 40.5 metres. The earthquake moved Honshu (the main island of Japan) 2.4 m (8 ft) east and shifted the Earth on its axis by estimates of between 10 cm and 25 cm.
On 12 September 2012, a Japanese National Police Agency report confirmed 15,883 deaths, 6,144 injured, and 2,676 people missing, as well as 129,225 buildings totally collapsed, with a further 254,204 buildings ‘half collapsed’, and another 691,766 buildings partially damaged. The earthquake and tsunami also caused extensive and severe structural damage in north-eastern Japan, including heavy damage to roads and railways as well as fires in many areas, and a dam collapse. Around 4.4 million households in northeastern Japan were left without electricity and 1.5 million without water.