To mitigate a volcanic eruption disaster, it is important to forecast the transition of the disaster, which depends on the stage of the volcanic phenomena, in addition to forecasting the site, scale, and time of the volcanic activities. To make such forecasts, it is critical to elucidate the evolution of volcanic activity. Accordingly, the Volcano Program Promotion Panel has set the prioritized target as “to forecast volcanic eruption as a cause of disaster by clarifying the branching conditions and theories of volcanic activity and improving volcanic event tree.” The panel promoted a five-year study on the elucidation of volcanic phenomena, including low-frequency and large-scale ones, status of volcanic eruption fields, volcanic eruption modeling, observation method development, and observation system improvement. In this paper, an outline of the main results of this five-year study is presented.

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