| Project/Area Number |
16K13872
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Solid earth and planetary physics
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| Research Institution | The University of Tokyo |
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Principal Investigator |
Takeo Minoru 東京大学, 地震研究所, 名誉教授 (00197279)
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| Project Period (FY) |
2016-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2016: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
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| Keywords | 火山 / 数理物理 / 固体地球物理 / 固体地球物理学 |
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| Outline of Final Research Achievements |
Long-period volcanic oscillations, such as a volcanic tremor, a long-period event, and a tilt motion, are closely associated with a volcanic eruption. Using observed data recorded near an oscillation source, we developed innovative methods to get parameters of nonlinear dynamics and to construct a mathematical model based on a topological approach. We applied these methods to analyses of volcanic tremors recorded during the 2004 eruption at Asama volcano and the 2011 eruption at Shinmoe-dake volcano. In the result, it made clear that the non-linear volcanic tremor in Asama volcano is caused by a blockage in the conduit, and that the harmonic tremor in Shinmoe-dake volcano are excited by a nonlinear instability that arises when viscous fluid flows through a partially constricted flexible channel.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究で開発したアプローチは，観測されたデータからその励起源の定性的な数理構造を推定する手法を提供するものである．この数理構造は，その火山性振動現象と噴火活動がどの様に関係するか，もしくは，その火山性振動を生み出す火道内部状態がどの様なものであるか，を推定する手がかりを与えるもので，火山噴火を理解する上での新たな知見をもたらすことが期待される．さらに，多くの火山で噴火に先行して同じ特徴を持つ振動現象が観測されており，火山性微動・地震の波動特性から火道内部状態を推定する手法が確立されれば，火山噴火の予測精度の向上に貢献をするものとなる．
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