Synopsis

Straddling the border between Nagano and Gifu prefectures, Mount Ontake rises to a height of 3,067 meters, drawing many hikers seeking a day of mountain adventure. During a September holiday, the mountain was thronged with climbers when a sudden phreatic eruption, triggered by groundwater, struck. The unexpected event sparked panic among those caught in its path. Why were the warning signs of this eruption so difficult to discern? Experts explain that volcanic eruptions manifest in three primary