カゴシマシ オヨビ サクラジマ ノ タイキ オセン ( コウバイ ) チョウサ ( ダイ8ホウ ) : ショウワ60ネンド チョウサ ホウコク

Volcanic ash from Mt. Sakurajima was collected together with rain water monthly from April 1985 to March 1986 at 14 locations in Kagoshima City and 7 locations on Sakurajima. After the samples had been filtered, the residue was dried and weighed, and the filtrate was analyzed for SO_4^{2-}, Cl^- and water-soluble matter. The amounts of sulfur oxides on PbO_2-candle were measured at the same locations as with ashfall measurement (except for 2 locations of Sakurajima). The average monthly ashfall at the 14 locations in Kagoshima City was 525 ton/km^2 and at the 7 locations on Sakurajima was 5,110 ton/km^2. Both values were the largest in those of the last 8 fiscal years (from 1978 to 1985). The largest amount of monthly ashfall in this fiscal year was 77,200 ton/km^2, which was recorded at Kurokami Middle School in September. This value is also the largest one of those recorded during the last 8 fiscal years. The falling weights of SO_4^{2-}, Cl^- and water soluble matter for this year were generally higher than those for the last year. The average amount of sulfur oxides absorbed on the PbO_2-candle on Sakurajima for this fiscal year was also larger than the corresponding average for the last year. The largest amount of the absorbed sulfur oxide was 3.10 mg/100 cm^2day, which was recorded at Arimura Haisuichi in February