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Major Mount Fuji eruption would shower about 1.5 cm of ash on central Tokyo: disaster management team

JIJI

A major volcanic eruption of Mount Fuji similar to the one that occurred in 1707 could leave ash 1 to 1.5 cm thick in central Tokyo over 15 days, according to a recent estimate released by a government team.

The layer of ash would exceed 3 meters in thickness at the foot of Japan’s highest peak, about 100 km west of central Tokyo, the working team of the central disaster management council said Friday.

The team made the estimates using wind data from Dec. 16 to 31 last year as those conditions are considered to be similar to what was seen at the time of the 1707 eruption.

Ash from the 3,776-meter mountain is also forecast to accumulate as far away as Chiba Prefecture.

The accumulation is seen reaching 1.2 meters in Gotemba in Shizuoka Prefecture, 45 cm in Hadano in Kanagawa and 10 cm in Yokohama. The amount would be 4.5 cm in Tokyo Bay and 1 to 1.5 centimeters in the capital’s Shinjuku Ward.

The team said roads will become impassable if the ash accumulation reaches 10 cm. It also said disruptions in aviation could be serious as well. Only 0.2 to 0.4 mm of ash would make it difficult to see signs and indicators on runways, possibly resulting in airport shutdowns.

The team will consider how to control traffic, remove and dispose of fallen ash and deal with other problems that would be caused by such an eruption.

The measures will be finalized by the end of March 2020 and reflected in local government disaster management plans.