| Project/Area Number |
18H01291
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 17030:Human geosciences-related
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| Research Institution | Niigata University |
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Principal Investigator |
Kataoka Kyoko 新潟大学, 災害・復興科学研究所, 教授 (00378548)
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| Co-Investigator(Kenkyū-buntansha) |
長橋 良隆 福島大学, 共生システム理工学類, 教授 (10292450)
卜部 厚志 新潟大学, 災害・復興科学研究所, 教授 (20281173)
M Satish‐Kumar 新潟大学, 自然科学系, 教授 (50313929)
齋藤 武士 信州大学, 学術研究院理学系, 教授 (80402767)
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| Project Period (FY) |
2018-04-01 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥17,030,000 (Direct Cost: ¥13,100,000、Indirect Cost: ¥3,930,000)
Fiscal Year 2021: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2019: ¥9,360,000 (Direct Cost: ¥7,200,000、Indirect Cost: ¥2,160,000)
Fiscal Year 2018: ¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000)
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| Keywords | 火山泥流 / ラハール / 小規模噴火 / 湖底堆積物 / 安達太良火山 / 磐梯火山 / 猪苗代湖 / 水蒸気噴火 |
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| Outline of Final Research Achievements |
Small-scale eruptions emplace small volume of primary tephra on steep slopes of volcanoes. These proximal tephra deposits are easily degraded due to rainfall, snowmelt, and wind soon after their deposition. Hence, the preservation potential in the geological record is low. This study aims to elucidate the history of small-scale eruptions and related lahars and to evaluate the frequency of eruptions. We analyzed the core samples obtained from the Sukawa Basin, Inawashiro Plain, and Lake Inawashiro in a lower catchment of Adatara and Bandai volcanoes. We recognized a number of lahar deposits and their runout subaqueous deposits, originated from Adatara and Bandai, intercalated in both fluvial and lacustrine sedimentary cores. The radiocarbon dating of these event deposits indicates the presence of unknown and more frequent eruption and lahar events than previously thought, and therefore, it is necessary to reassess the eruptive history and activity at these volcanoes.
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| Academic Significance and Societal Importance of the Research Achievements |
過去の小規模噴火による噴出物は，堆積量も少なく，侵食・風化作用により，地層中に保存されにくい。そのため，火口近傍の地層の解析のみに基づく，個々の火山における小規模噴火の履歴や活動度の全貌は明らかではない。また，国内における火山泥流の堆積物を用いた研究も極限られてきた。噴火の情報を含んだ火山噴出物は，噴火時と噴火直後に発生する火山泥流に取り込まれ，火山からやや離れた下流域に運搬・堆積し，火山泥流堆積物中に保存される。本研究は，その特性に着目し，火山下流域の地層の詳細な解析に基づき，過去の小規模噴火とそれに関わる火山泥流の発生履歴と周期性を明らかにし，より実態に近い噴火活動を復元した。
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