A disaster of unimaginable scale looms over Japan as its government is warning that the next ‘megaquake’ could kill as many as 300,000 people.
Such a seismic monster – which could trigger a tsunami powerful enough to obliterate entire coastal regions off the Pacific coast – has been feared for a long time.
Towering waves that would sweep away infrastructure and leave nothing but devastation in its wake.
There are concerns it is a matter of when – not if – after the government sounded the alarm in a report published on Monday.
The figures have been updated from a previous estimate, made in 2014, for the potential consequences of a huge earthquake along the Nankai Trough south of Japan.
The 500-mile undersea trench runs from Shizuoka, west of Tokyo, to the southern tip of Kyushu island.
It is where the Philippine Sea oceanic tectonic plate is ‘subducting’ – or slowly slipping – underneath the continental plate that Japan sits atop.
The plates become stuck as they move, storing up vast amounts of energy that is released when they break free, causing potentially massive earthquakes.
The Cabinet Office’s disaster management working group said up to 215,000 people would be killed by a tsunami, 73,000 by the collapse of buildings and 9,000 by fire.
But the predicted toll as a whole is lower than the 2014 estimate which said that up to 323,000 people would die.
Over the past 1,400 years, such megaquakes in the Nankai Trough have happened every 100 to 200 years.
The last one happened in 1946, but scientists say it is extremely difficult to predict them.
In January, a government panel said the probability of such a disaster in the next 30 years has marginally increased, with a 75-82% chance of it happening.
Last August, the Japan Meteorological Agency (JMA) issued its first ever ‘megaquake advisory’ under rules drawn up after the devastating 2011 earthquake, tsunami and Fukushima nuclear disaster.
It said that the likelihood of a new major earthquake along the Nankai Trough was higher than normal after a magnitude 7.1 jolt in southern Japan which injured 14 people.
The advisory was lifted after a week but caused shortages of rice and other staples as people replenished their emergency stocks.
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