Mount Fuji full-scale volcano eruption could cripple Tokyo, warns Japanese govt panel

A full-scale volcano eruption of Mount Fuji in Japan would rain so much ash on the capital city of Tokyo that its transportation network of trains and highways would be crippled within three hours, according to a Japanese government panel, according to a Japanese media. The effects spreading to the entire greater Tokyo metropolitan area would be witnessed by the second day.

A committee under the Japanese government’s Central Disaster Management Council released its study on March 31. Mount Fuji last erupted more than 300 years ago in 1707.

The conditions of those, already suffering from respiratory problems such as asthma or bronchitis, would worsen. The outcome of an eruption, even if there was a small volume of volcanic ash dumped, would be devastating as roads would become unusable, there would no power, food and product deliveries would stop and debris, approximately 10 times the amount of 2011 disaster, would have to be cleared. Visibility would diminish to zero, according to the local media.

The effect would also be witnessed on the water supply, either by impurities entering the water supply or because of the supply being cut off completely. 

The panel calculated that if more than three cm of ash accumulated in an area, at least 1,000 bulldozers and other heavy equipment would be needed to clear it for three entire days. Airport runways would be unusable with only between 0.04 and 0.20 cm of volcanic ash resulting in a severe restriction on the number of flights. It added about the possibility of large ships unable to navigate into Tokyo Bay due to poor visibility, according to the local media.

Thermal power plants would be unable to operate if more than 6 cm of ash fell. Mobile phone networks would also be severed if volcanic ash piled up on communication antennas because of rain. Wooden homes could collapse if more than 30 cm of volcanic ash accumulated on rooftops during rain.

The committee has asked the local governments and infrastructure companies to compile disaster management plans beforehand, adding that evacuations should take place before an eruption. The panel added that the figures would also be greatly affected by the weather as well as wind direction and speed, according to the local media.

Japan is one of the world`s most seismically active nations and is rocked by earthquakes and volcanic eruptions on an annual basis. In 2014, it suffered its worst volcanic disaster in over 90 years when a peak crowded with hikers blew up without warning, killing 63. Japan has 110 active volcanoes and monitors roughly half of them, but researchers say the budget has always been smaller than that for earthquakes and lacks sufficient equipment. Of Japan`s nine major volcanic eruptions since 1977, the longest warning was a week.