Reports on Volcanic Activities and Volcanological Studies in Japan

for the Period from 1995 to 1998


I. Preface

In the year of 1995, the Volcanological Society of Japan has just attained the 40th year of its activities and published the special volume of the Bulletin to commemorate an important anniversary of its foundation. Many of the great advances of volcanology in Japan have been recorded in the regular issues of the Bulletin, which are written mainly in Japanese with English abstracts and figure captions.

The continued progress of volcanological studies in Japan, especially in the fields of geophysics and geochemistry, have been mainly based on the National Project for Prediction of Volcanic Eruptions, which started in 1973. In this project, we aimed at grasping the activity of volcanoes, predicting the time and place of eruptions and foreseeing the development of the eruptive stages. The purposes of the project were realized to a considerable extent in the long-lasting eruptive activity at Mt. Unzen. Disastrous eruptive activity of Mt. Unzen that started in 1990 with the growing lava dome, the associated pyroclastic flows and debris flows terminated eventually in the middle of 1996. This eruption had a wide and significant influence upon not only the various aspects of volcanological studies in Japan but also the perceptions of volcanic hazards. We believe that the documents reporting this eruption and related phenomena will provide significant contributions to the science of volcano.

Before finishing the fifth plan of the National Project for Prediction of Volcanic Eruptions (1994-1998), the symposium on prediction of volcanic eruptions (Views toward the 21th century) was held in May 1996, by the National Committee of Volcanology and Chemistry of the Earth’s Interior, Science Council of Japan, and jointly by the Volcanological Society of Japan. The three topics including “what level have we reached for prediction of volcanic eruption?” were extensively discussed. Another critical review on the progress of this national project during the period from the its beginning to the present was also carried out by the Geodetic Council, Ministry of Education, Science, Sports and Culture (Monbusho) in 1996. The long-term project was evaluated positively, on the whole, in need of furthermore progress of the researches and observations. Based on this evaluation, new proposal as next 5-year plan (sixth planing for 1999-2003) was presented to the Government and was approved in 1998. In collaboration with volcanologists throughout Japan, we are firmly intent on continuing the researches and observations on various types of volcanic activity.

Recent research highlights and various studies on geophysics, geochemistry, and geology are reviewed in the following pages. We sincerely hope that this report will be conducive to an international understanding of the Japanese contribution to volcanology and chemistry of the Earth’s interior.

May 1999

Hiroyuki Hamaguchi

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