阿蘇山の長周期火山性微動について ―第2種火山性微動と火山性微小地震の関係―

Abstract

The 2nd kind volcanic micro-tremors appear correspondingly to the volcanic micro-earthquakes.Strictly speaking, a conspicuous phase (C phase) can be seen at the place about ten seconds afterthe initial motion of a volcanic micro-earthquake and the appearance of this phase is simultaneouswith that of the principal part of the 2nd kind volcanic micro-tremor. Time intervals (C-P interval)between the initial motions and the C phases of the volcanic micro-earthquakes are related to theratios of the maximum amplitudes between the initial motions and the C phases to that of the Cphases. In order to explain these phenomena, the foci of the volcanic micro-earthquakes are deter-mined. The deeper a focus is, the shorter the C-P interval becomes.