The school beneath the wave: the unimaginable tragedy of Japan’s tsunami

In 2011 a tsunami engulfed Japan's north-east coast. More than 18,000 people were killed. Six years later, in one community, survivors are still tormented by a catastrophic split-second decision. By Richard Lloyd Parry

The earthquake that struck Japan on Friday 11 March 2011 was the fourth most powerful in the history of seismology. It knocked the Earth six and a half inches off its axis; it moved Japan four metres closer to America. In the tsunami that followed, more than 18,000 people were killed. At its peak, the water was 40 metres high. Half a million people were driven out of their homes. Three reactors in the Fukushima Daiichi power station melted down, spilling their radioactivity across the countryside, the world's worst nuclear accident since Chernobyl. The earthquake and tsunami caused more than $210bn of damage, making it the most costly natural disaster ever.

Pain and anxiety proliferated in ways that are still difficult to measure, even among people remote from the destructive events. Farmers, suddenly unable to sell their produce, killed themselves. Blameless workers in electricity companies found themselves the object of abuse and discrimination. A generalised dread took hold, the fear of an invisible poison spread through air, through water - even, it was said, through mothers' milk.