| Project/Area Number |
16510134
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Natural disaster science
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| Research Institution | Hokkaido University (2006)
The University of Tokyo (2004-2005) |
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Principal Investigator |
YOSHIMOTO Mitsuhiro Hokkaido Univ., Faculty of Science, Research Associate, 大学院理学研究院, 助手 (20334287)
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| Co-Investigator(Kenkyū-buntansha) |
KANEKO Takayuki Univ. of Tokyo, Earthquake Research Inst., Research Associate, 地震研究所, 助手 (90221887)
FUJII Toshitsugu Univ. of Tokyo, Earthquake Research Inst., Professor, 地震研究所, 教授 (00092320)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2006: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2005: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2004: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Fuji volcano / Volcanic History / Mud flow / Boring core / 土石流 / 火山帯形成史 |
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| Research Abstract |
Mt. Fuji is a composite stratovolcano consisting of four volcanoes; Pre-Komitake, Komitake, Ko-Fuji (Old Fuji) and Shin-Fuji (Young Fuji) volcanoes in order of decreasing age. The Aim of this study was to obtain volcanic history of Mt Fuji using the core samples drilled at northeastern flank of the volcano by ERI, Univ. of Tokyo in 2001-2003.
In the drilled cores, hornblende-bearing andesite and dacite together with basalt were found as lava flows and fragments in mud flows below the Komitake volcanic rocks which contain olivine-bearing plagioclase-phyric two-pyroxene basaltic andesite (51-53 % SiO2). The volcano whose activity produced these basalt to dacite (50-70 % SiO2) was called pre-Komitake Volcano. As a thin soil layer was found just above the pre-Komitake volcanic rocks, the activity of Komitake volcano started after a short depositional hiatus following that of pre-Komitake Volcano. It ended its activity about 100 ka roughly together with that Ashitaka Volcano. Subsequently, Fuji Volcano shifted the activity center south of Komitake Volcano and huge amount of basaltic ejecta were issued.
Deposits of eastern flank of Ko-Fuji volcano before 30ka composed mainly of mudflow deposit derived from scoria fall, in contrast to scoria fall deposit after 30ka.It is possible that those conversion of deposit was caused by existence of summit glacier associated with climate change.
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