No. 36 Mt. Fuji Science Institute

(public information Inagi October 15, 2014 issue publication)

On August 22, 2014, we visited the Fujisan Science Research Institute in Yamanashi Prefecture as part of a joint training session of the Tokyo Metropolitan Association of Mayors, and listened to a lecture by Director Toshitsugu Fujii.
After obtaining his doctorate in science from the University of Tokyo's Graduate School, Mr. Fujii worked at the University's Earthquake Research Institute, where he served as director, and since 2003 he has been appointed chairman of the Japan Meteorological Agency's Volcanic Eruption Prediction Coordination Committee. It's home.
The topic of that day's presentation was ``The origins of Mt. Fuji and the impact of its eruption on the Tokyo metropolitan area.'' Mt. Fuji was registered as a World Cultural Heritage Site last June, and this facility was renamed from the "Environmental Science Research Institute" to the "Fujisan Science Research Institute" in April of this year. The media and locals are in a celebratory mood, but the theme of this event was to remind us that this mountain is an active volcano.
Active volcanoes include not only those that are currently actively producing fumarolic activity, but also those that have erupted in the last 10,000 years. It may be strange to think that something that has not erupted for 10,000 years is an active volcano, but Chile's Chaitén volcano, which erupted for the first time in 9,400 years without any prior warning, erupted 27 hours after the first earthquake was detected. Therefore, we cannot let our guard down.
Japan is home to 110 active volcanoes, or 7% of the world's active volcanoes, so it's no wonder that Japan is one of the world's most earthquake-prone countries. Among these, the ones whose eruptions affect the metropolitan area are Mt. Hakone, Mt. Asama, and Mt. Fuji.
Mt. Hakone is the closest volcano, and pyroclastic flows were generated during a major eruption 65,000 years ago, leaving pumice layers around 20 centimeters thick in some places in Tokyo. The major damage is Mt. Fuji, and the Hoei eruption 300 years ago caused ash fall of about 2 to 10 centimeters in Tokyo. Although large volcanic bombs do not seem to reach directly from Mt. Fuji, volcanic ash is carried by westerly winds and accumulates over a wide area.
I'm worried that the eruption of Mt. Fuji is difficult to predict with current knowledge, but the only hope was that statistically there is a high probability that the next eruption will be small.
Environmental measures remain to be completed in the registration of Mt. Fuji as a World Cultural Heritage Site, and if they are not done, the registration may be cancelled. Among the points raised was ``There is an urgent need for a contingency plan that would work in the event of an eruption or fire.''
Since the Great East Japan Earthquake, we have been making efforts to eliminate unexpected events, but it seems that it will be difficult to protect against the eruption of Mt. Fuji. However, it is necessary to plan for recovery after a disaster. Up until now, the Inagi City Regional Disaster Prevention Plan has focused on measures against earthquakes, wind and flood damage, but through this training, I felt that volcanic eruptions should also be a research topic in the future.