Tsunamis in Japan

Most severe events

The biggest consequences so far in terms of human lives, injuries, destroyed houses and the economy were caused by a tsunami on March 11, 2011. A wave of up to 55.88 meters in height killed 15,950 people and destroyed large areas. It was triggered by a seaquake at a depth of 32 km with a magnitude of 9.1 off the Sanriku coast. More than 470 km² of land were flooded. Nearly half a million Japanese had to be evacuated. The effects were particularly drastic as the Fukushima nuclear power plant was hit by a 14-meter-high tsunami wave. The reactors were so badly damaged that radioactive material leaked out and spread over numerous localities. Following the tsunami, a 20-km exclusion zone was established and over 160,000 people were relocated.

Tsunamis as a result of earthquakes

Japan is located at the boundary of several tectonic plates and in the northwest of the Pacific Ring of Fire. Off the west coast, the Amur Plate of the continental shelf, the Philippine Plate, the Pacific Plate and the Okhotsk Plate, which drifts southward from the north, collide. The continental drift causes the plates to push among or along each other. The seismic activity is normally low and not noticeable. However, pressure builds up at the kilometer-thick plate edges, which is released by earthquakes.

Tsunamis are caused by earthquakes or other seismic eruptions in oceans and sometimes result in massive waves that run onto land with enormous force, causing great devastation. Even relatively small tsunami waves can thus lead to high losses and financial damage. Japan is a country that regularly experiences earthquakes and tsunamis. Safety precautions were considered exemplary before the 2011 quake, especially since the risk was considered high, particularly on the Tōhoku coast near Fukushima. However, such a violent quake and the consequences of its magnitude, proximity and geography were not expected, and the extent of the flooding was underestimated.

The marked positions on the map represent the most affected regions within the past 1,300 years.

The largest tsunamis in Japan since 1498

These evaluations are based on data from the Global Historical Tsunami Database of the National Geophysical Data Center, NOAA, and World Data Service (NGDC/WDS), doi:10.7289/V5PN93H7. Individual data have been summarized or translated.