How prepared is Tokyo for giant earthquake that could kill 10,000 people and destroy 300,000 buildings?

Every day, at 5pm, the gentle melody of the children’s song Yuyake Koyake chimes across the Minato area of Tokyo from a loudspeaker – one of hundreds dotted across schools and parks throughout this megacity of 37 million people.

The last great quake to hit Tokyo was in 1923. Experts estimate the next one is due roughly a century on, with an estimated 70 per cent chance of a magnitude-7 quake hitting Tokyo before 2050. It is no longer a question of if – but when – the big one will come.

The impact would be devastating. According to an official estimate, a magnitude-7.3 quake striking northern Tokyo Bay could kill 9,700 people and injure almost 150,000. There would be an expected peak of 3.39 million evacuees the day after the disaster, with a further 5.2 million stranded, while more than 300,000 buildings could be destroyed by the earthquake itself or the ensuing fires.

It would be the most calamitous event to confront Tokyo since the US firebombing of March 1945 that killed 100,000 people and burned down more than 267,000 buildings.

When the magnitude-7.9 Great Kanto earthquake struck beneath Oshima Island, about 100km south of central Tokyo, around lunchtime on September 1, 1923, thousands of buildings collapsed. Fires broke out in homes as cooking stoves overturned, and people who escaped described the aftermath as hell on earth. The combined death and injury toll was officially estimated at 105,000 across Tokyo and the adjacent port city of Yokohama, although some reports said it was far higher.

In the chaotic aftermath of the disaster, false rumours about a “Korean revolt” and the alleged poisoning of wells also triggered outbreaks of deadly mob violence against Koreans.