Investigation of the internal structure of the lava dome in Showa Shinzan, Usu volcano, japan, from seismic, gravimetric, and muographic observations
| Project/Area Number |
17K05625
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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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 |
AOKI Yosuke 東京大学, 地震研究所, 准教授 (90376624)
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| Co-Investigator(Kenkyū-buntansha) |
西田 究 東京大学, 地震研究所, 准教授 (10345176)
青山 裕 北海道大学, 理学研究院, 教授 (30333595)
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| Project Period (FY) |
2017-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2020: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2018: ¥260,000 (Direct Cost: ¥200,000、Indirect Cost: ¥60,000)
Fiscal Year 2017: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
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| Keywords | 地震波速度構造 / 火山性地震 / 地震波干渉法 / 溶岩ドーム / 地震観測 / 表面波トモグラフィ / 微動 / 合成開口レーダー / 地震波雑微動トモグラフィ / 溶岩ドームの内部構造 / 重力観測 / ミュオン・ラジオグラフィ |
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| Outline of Final Research Achievements |
The goal of this study is to understand the mechanics of the emergence of a lava dome. To achieve the goal, we conducted a seismic experiment in Showa-shinzan, a lava dome emerged during the 1943-1945 eruption of Usu Volcano, northern Japan. We imaged the seismic velocity structure beneath the lava dome by seismic interferometry using ambient seismic noise. Our results image a high-velocity body beneath the lava dome, indicating that the lava dome is mainly composed of actively intruded magma, rather than passive uplift of the surface. Also, we fortuitously found previously unidentified volcanic earthquakes that may result from thermal cooling of the intruded lava. Details of these earthquakes will be investigated later.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究計画では、高粘性マグマが関わる噴火の際に多く見られる溶岩ドームの地震波速度構造を明らかにすることを通して、溶岩ドームの生成メカニズムに新しい知見を加えることができた。溶岩ドーム噴火は、溶岩ドームの崩壊により火砕流を引き起こし、これまでに多くの被害をもたらしてきたことから、今後の研究の発展により、溶岩ドーム噴火による被害の予測およびその軽減がなされると考えられる。
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Report
(5 results)
Research Products
(1 results)
