Sun. May 21, 2017 9:00 AM - 10:30 AM A08 (Tokyo Bay Makuhari Hall)

convener:Kei Kurita(Earthquake Research Institute,University of Tokyo), Hidefumi Watanabe(Disaster Prevention Division, Tokyo Metropolitan Government), Chairperson:Kei Kurita(Earthquake Research Institute,University of Tokyo), Chairperson:Hidefumi Watanabe(Disaster Prevention Division, Tokyo Metropolitan Government)

1986 Izu-Ohshima eruption has revealed several significant problems, which disclosed unmatured state of volcanology at that moment. The most significant situation was that the eruption style as well as the eruption site shifted with time during the course of eruption episodes. The volcanologists were faced the social demands for immediate response towards the transient behavior. This eruption may be the first occasion where the volcanologists deeply recognized the importance of real-time monitoring of the eruption activity. Why the eruption sequence changed? How did the observations trace the shift and how was the prediction of the shift possible?, these problems are still unanswered today. In this 100 years Izu-Ohshima erupted repeatedly with the interval of 30-40 years. Already 30 years have passed since last eruption so that we could consider next eruption. In this session we plan reconsiderations on 1986Izu-Ohshima eruption based on state-of-the-art concept of volcanology. Particularly new results have appeared recently by the reanalysis of the old data of strain meters and seismometers as well as the reanalysis of the samples by recent techniques. These results have revealed new aspects of the eruption. We will combine these data with the unanswered problems in the session.