桜島の爆発地震について

概要

論文の詳細を見る
The present author analysed statistically explosion smokes, explosion-earthquakes and explosion-air-vibrations of the volcano Sakurazima. Sakurazima is one of the most active volcanos in Japan, and explosive eruptions at the summit crater have been taking place frequently since 1955. Features explosion activity are shown in Fig. 4 or Table 2. There were close relations between frequency of explosion-earthquakes and total energy of them, but, generally speaking, larg explosions did not occur during any period of swarm of small explosions. Energy of explosion-earthquakes gradually increased until a new crater was born in 1964 at the rim of the old crater, and after that, it decreased. Energy of each explosion-earthquake which is classified according to the quantity of explosion smokes has an upper limit value. On the other hand, frequency distribution of maximum amplitudes of explosion-earthquakes or that of explosion-air-vibrations which examined by Ishimoto-Iida's method is not expressed by a straight line on a diagram with both logarithmic scales, but by an upward convex curve. These phenomena are explained by assuming that explosive destructions occur only in a narrow vent.
1967-04-01