The 1962 Eruption of Miyake-sima, One of the Seven Izu Islands, Japan

Abstract

Volcano Miyake-sima erupted on August 24, 1962, after a long repose of 22 years. The recent eruption was almost similar with the 1940 activity with respect to the magnitude of eruption, the mode of eruption and the locality of the newly opened craters. The 1962 eruption was followed by severe and numerous earthquakes. The 8000 persons on the Miyake-sima island became extremely uneasy, because they feared if another new crater might be opened. Fortunately, any other crater was not opened. Soon after the eruption took place, the writers made the seismometric observation by setting the acceleration seismograph of vertical and horizontal components at five stations at the margin of the island. Beside these ordinary seismographs a pair of vertical and horizontal transducers of the telerecording system was set at the central part of the island. From the result of the observation, we made clear the localities of hypocenters and the mode of the geographical distribution of the initial motion of earthquakes.