M9.0 Tohoku earthquake and tsunami strike Japan's northeast coast

On 11 March 2011 a magnitude 9.0 earthquake struck off Japan's Pacific coast, along the Japan Trench, where the Pacific plate slides beneath the plate carrying northern Japan. It was the strongest earthquake ever recorded in Japan.

The rupture generated a huge tsunami that swept over coastal towns in the Tohoku region in the northeast, destroying homes, harbours and farmland. Roughly 20,000 people were killed or left missing, most of them by the waves, and hundreds of thousands were displaced.

The tsunami also flooded the Fukushima Daiichi nuclear plant, knocking out its cooling systems and causing meltdowns in several reactors. Radiation releases forced the evacuation of surrounding communities, and the disaster led Japan to shut down its nuclear fleet for safety reviews.

The waves crossed the Pacific and reached the US West Coast, where ports such as Crescent City, California, suffered damage. The event reshaped Japan's disaster planning and remains the reference point for scientists studying how the Japan Trench builds up and releases stress.