桜島火山1914年噴火の噴煙高度 : 目撃資料の検討

概要

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Associated with the 1914 great eruption at Sakurajima volcano, southwestern Japan, the maximum height of volcanic cloud is discussed based on collected documents, sketches and photographs in those days. A series of photographs up to around 10 : 40 on January 12 (in Japanese Standard Time) represents that the volcanic cloud height attained to 7,000 to 8,000 m above sea level. After then, it proved that several documents reported the height to be 9,500-15,000 m, or even more than 18,000 m a.s.l, although it is difficult to obtain reliable evidences. Considering these reports and other observations from a distance, the height of 15,000 m is tentatively proposed here as a possible maximum value. According to an empirical relation, an eruption rate of small pyroclastic materials is suggested as, roughly speaking, 5,000 tons per second or 20 millions of tons per hour, if the volcanic cloud was 15,000 m in height.
1999-04-30