An inhabited volcanic island of moderate size like Miyake-jima (8×9km approx.), which is located at about 200km south of Tokyo, would be a suitable site for an investigation of natural and social systems on an active volcanic island applying a transdisciplinary approach. A group study on this line in the University of Tokyo has commenced since 1981 with seven members who major in volcanology, paleontology and geological history, geochemistry, botany, ornithology, animal ecology, and coastal biology respectively, to establish a long-term study for coming ten years. In this circumstances, on October 3, 1983 the Miyake island erupted along a fissure which run in the caldera and on the flank ofthe old somma to reach the southern coast. One of the lava flows spilt over the caldera wall and buried the Ako area with more than 400 homes. The 4.5km long fissure eruption lasted about 13 hours at least, and some explosion craters were formed in the coastal region. An unusually remarkable fact is that fortunately no one was dead nor seriously injured with this 1983 Miyake eruption.
Our group study immediately treated this volcanic activity as one of the transdisciplinary themes. This article contains some preliminary results of our investigation as follows:
I. Preface, II. A transdisciplinary scope of the study on volcanoes, III. Characteristics the 1983 eruption, IV. Some remarkable facts observed: 1. Gust caused by a curtain fire, 2. Asymmetrical arrangement of ejecta from the fissure, 3. Subsurface coralline evidenced by the ejecta of phreatomagmatic explosions, 4. Sequence of phreatomagmatic explosions, V. Effects on the island flora and fauna by the eruption: 1. Bombing the ejecta, 2. Recovery and transition of vegetation after heavy ash disaster, 3. Impact the eruption on the avian fauna, 4. Submarine biotic communities, VI. Changes of social environment of the island for this past one year after the eruption, VII. A further scope the study.

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