桜島火山に於ける地震観測について(第5報)

Abstract

In order to predict a volcanic explosion one day before, the vulnerability rates of explosion, which are done at Asama by Dr. Minakami, are culculated using data of volcanic micro-earthquakes at Sakurajima.Vulnerability rates do not increase with the number of earthquakes. This means that thevulnerability rates method is not effective for Sakurajima volcano at the present time.Since September 1963, the number of observed earthquakes rose 3 x i0~', and Ishimoto-lida'srelation was examined. At the nearest station from the active crater, the maximum amplitudeand frequency relation is not expressed by a linear line in both logarithmic scale, but byan upward concave. On the other hand, at the other 2 stations, which are away from theactive crater, the max. amplitude and frequency relation is expressed by a line. This impliesthat, the maximum amplitude and frequency relation at the origin, is not expressed by a linesrline in both logarithmic scale.