A government panel called on the central and local governments Thursday to draw up evacuation plans for large-scale volcanic disasters.
The Cabinet Office panel, chaired by Toshitsugu Fujii, a professor emeritus at the University of Tokyo, submitted the same day what are considered the first government-proposed eruption countermeasures. They were handed to Keiji Furuya, minister in charge of disaster prevention.
“Large-scale volcanic disasters could occur by the end of this century,” the report said, with an eye on Mount Fuji and Sakurajima, an active volcanic island in Kagoshima Prefecture, although of 110 volcanic mountains nationwide, 47 are being monitored around the clock for signs of a possible eruption in the coming decades.
For large-scale volcanic disasters, the panel envisages eruptions that produce at least 100 million cu. meters of pyroclastic discharge, including volcanic ash and lava.
Although a large-scale eruption could force mass evacuations, detailed hazard and evacuation maps for each volcano, to cope with such events, have not been compiled, the panel said, proposing that the central and local governments work together to forge such plans.
The panel warned that volcanic ash accumulations of even 1-2 cm could prevent evacuation by vehicle. It thus urged authorities to choose priority roads and facilities that would be cleared of ash first and build a system to ensure safe evacuation routes.
Eruption warnings have not been issued when only falling ash is observed. The panel emphasized the need to lay out criteria for deciding when to order an evacuation or just advise people to stay indoors, and urged that regional governments take the initiative on such actions.
The panel noted, for example, that when Mount Fuji erupted in 1707, it spewed 1.7 billion cu. meters of ash over 16 days. When Sakurajima had a large eruption in 1914, lava amounting to 1.5 billion cu. meters flowed over a two-week period, joining the island with Kyushu’s Osumi Peninsula.