Effects of Ash Fall from Mt. Fuji Eruption on the Contemporary Metropolitan Area

Since the 2011 magnitude 9 off the Great East Japan earthquake, Japan is said to have entered a period of seismic activity. When a magnitude 9-class earthquake occurs, volcanic activity usually increases in the surrounding area, and in Japan, volcanic eruptions have become more active since 2011.In light of this situation, if an eruption and ash fall of the same magnitude as the eruption of Mt. Fuji that occurred approximately 300 years ago(1707) during the Edo Period were to occur today, the impact, damage, and countermeasures would be incomparably more difficult than in the Edo Period.

　Mt. Fuji eruption during the Edo Period the continued intermittently for about two weeks, causing ash fall damage not only to the area around Mt. Fuji but also to the town of Edo with the final ash fall estimated to have been 3 to 10 cm. However, damage to houses, roads and water sources, no major damage occurred except some damage to crops in the fields.

One of the major differences between the Edo period and modern society is the vastly different structure and character of the various types of living infrastructure. Especially transportation infrastructure such as roads, railroads, and airports; and daily life infrastructure such as electricity, communications, water, sewage, and gas; supply of food and other essential goods; and the nature of businesses, schools, and hospitals are very different between the Edo period and today. Therefore, the impact of ash fall on society is expected to be incomparably more damaging than it was then.