On 11 March 2011, at 14:46 local time, a massive earthquake occurred off the Pacific coast of Japan. Its epicentre was approximately 70 km east of Japan’s Oshika Penisula, while its hypocentre was 35 km underwater. With a magnitude of Mw 9.0, this was the strongest earthquake ever to hit Japan and one of the five most powerful earthquakes measured in the world since modern record keeping began in 1900.
Such was the earthquake’s force that it moved the island of Honshu – Japan’s mainland, or largest island – 2.4 m east, and is also believed to have shifted the earth on its axis by between 10 cm and 25 cm.
The earthquake triggered a massive tsunami which reached Japan’s east coast in less than one hour. Like the earthquake, the tsunami’s severity was unprecedented, both in height and reach. A number of coastal cities were completely inundated. In the northern city of Miyako, the flooding from the tsunami reached a height of 40.5 m. In some of the rivers in Sendai plane, the tsunami impacts could be felt up to 10 km upstream.