Research for the volcanic activity of Fuji Volcano, based on the tephrostratigraphy of lake sediments from Lake Yamanaka, central Japan

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This research was carried out to make the volcanic activity and eruption history of Fuji volcano to reach over the past several ten thousand based on the tephrastratigraphy of the lake bottom sediments, YA-1 and 2 cores collected from Yamanaka Lake clear. Microfossil analysis was done together, and cleared as for the influence of the eruption activities as well.Those characteristics were explained, and correlation with the tephra distributed in the land part was done about the tephra in YA-1, 2 cores. This result revealed that there was partly an unconfirmed tephra. As the widespread volcanic ashes, it was found that tephra in YA-1 core about 7.4m in depth correlated to Kg, and tephra in YA-1 core, 11.8m depth and YA-2 core, 6m depth done to K-Ah, too. Based on carbon fourteen dating and tephrastratigraphy, scoria layer in YA-1 core, 0.8m in depth correlated to Hoei scoria in 1707AD.Microfossil analysis, as pollen fossil, phytolith and so on, were done by using the core of YA-1 collected from center of Yamanaka Lake to explain impact of the volcanic eruption. Though the remarkable influence of the volcanic eruption couldn't be read as yielded rich arboreal pollen, wood floor was damaged due to increasing and decreasing of the non arboreal pollen and spore analysis in tephra falling.These results seem to contribute the preparation of the volcanic disaster map and the foundation materials in protection against disasters.