This year’s centenary of the disaster has occasioned much commemoration — and angst. What will happen when the next Big One hits? Seismologists cannot predict earthquakes, but their statistical models, which are based on past patterns, can estimate the likelihood of one. The city government’s experts reckon there is a 70% chance of a magnitude 7 or higher quake hitting the capital within the next 30 years. Far fewer people will probably die than during the disaster in 1923, thanks to better technology and planning: the worst case foresees some 6,000 deaths in the city. But millions of lives will be upended.
Another, similarly likely scenario could be much worse. A Nankai Trough earthquake, envisaged south of Kansai, Japan’s industrial heartland, could trigger a tsunami; as many as 323,000 might be killed, according to an official estimate. Japan’s approach to the risks of such catastrophes offers insights for a warming world facing more frequent disasters. Quakes of this size could “challenge the survival of Japan as a state” and send economic shock waves around the globe, says Fukuwa Nobuo of Nagoya University. After the next Tokyo quake, recovering basic city functions could take weeks and rebuilding the capital could take years; direct damage alone could run to as much as $75bn. One piece of research estimates that gdp would dip by 11% following a Nankai earthquake.
