著者

池辺 伸一郎 藤岡 美寿夫

出版者

特定非営利活動法人 日本火山学会

雑誌

火山 (ISSN:04534360)

巻号頁・発行日

vol.46, no.4, pp.147-163, 2001

参考文献数

28

被引用文献数

1 2

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Yunotani spa is located to the west part of the Central cones of Aso Volcano. Since the 14th Century, many people have been visiting this hot spring. A few explosions were referred in an old document "Nagano-ke-nikki; Diary of Nagano family". However, the details of these events are not yet clear. We have found a set of historical records on the explosion called "Yunotani Catastrophe" that took place at the solfatara of Yunotani spa in July 6, 1816. These records, two drawings and five reports on the explosion, describe the events and damages in detail. A lot of "hot-mud" with many blocks were ejected from two vents, and destroyed 12 bathrooms and injured one person in the area about 100 m from the vents. Judging from the descriptions and occurrences of the hydrothermally altered ejecta around the vents, it can be said that this event was caused by steam explosions from the solfatara. By the revelation of these records, it became clear that an explosion occurred not only at Naka-dake but also in the area outside of Naka-dake in the historic age. This fact is important for the prevention of volcanic disaster in Aso Volcano.