Quantitative verification of simultaneous super eruptions by using paleomagnetic directions and secular variation
Project/Area Number |
16K01311
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Research Field |
Natural disaster / Disaster prevention science
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Research Institution | Ibaraki University |
Principal Investigator |
Hasegawa Takeshi 茨城大学, 理工学研究科(理学野), 准教授 (00574196)
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Co-Investigator(Kenkyū-buntansha) |
岡田 誠 茨城大学, 理工学研究科(理学野), 教授 (00250978)
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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 |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2017: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2016: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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Keywords | 火山 / 噴火 / 古地磁気 / 地質学 / 編年学 / 火山灰 / 火砕流 / カルデラ / 年代測定 / 巨大噴火 / 古地磁気学 / 巨大同時噴火 / 国際比較研究 / 広域テフラ / 古地磁気方位 / 永年変化 |
Outline of Final Research Achievements |
Several cases of "simultaneous super eruptions" have been suggested based on geologic observations of ash layers in the world volcanoes. I verified about the 5 examples (in Japan and New Zealand) by using paleomagnetic directions and secular variation that provides a unique quantitative assessment.The data infer that there is no evidence of simultaneous eruptions but each eruption occurred with considerable time gaps of tens to hundreds years. One example occurred during a geomagnetic excursion that is a brief event with a faster rate of magnetic pole wandering. This example should be more investigated to estimate correct time gap with high resolution in future.
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Academic Significance and Societal Importance of the Research Achievements |
歴史上において、巨大噴火の目撃例自体がほとんどない。これまで地層だけを見て「同時巨大噴火」と指摘されていた事例について、はじめて定量的データを基に解析し、同イベントは地球上で一般的な事象ではないことを明らかにした。未知の噴火現象について、定量的な評価を与えたことは、防災対策などの社会的要請にも資する成果である。また、本研究で開発したこの定量法(すなわち、当時の地磁気方位の差と地磁気極の変化速度から経過時間を見積もる方法)は、巨大噴火に限らず火山灰全般に適用可能であり、今後、火山学、地質学、編年学などの学術分野の進展に大きく貢献しうるものである。
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Report
(5 results)
Research Products
(39 results)
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[Journal Article] Upper Triassic mafic dykes of Lake Nyos, Cameroon (West Africa) I: K-Ar age evidence within the context of Cameroon Line magmatism, and the tectonic significance2018
Author(s)
Festus Tongwa Aka, Takeshi Hasegawa, Linus Anye Nche, Asobo Nkengmatia Elvis Asaah , Mumbfu Ernestine Mimba, Isidore Teitchou, Caroline Ngwa, Yasuo Miyabuchi, Tetsuo Kobayashi, Boniface Kankeu, Tetsuya Yokoyama, Gregory Tanyileke, Takeshi Ohba, Joseph Victor Hell, Minoru Kusakabe
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Journal Title
Journal of African Earth Sciences
Volume: 141
Pages: 49-59
DOI
Related Report
Peer Reviewed / Int'l Joint Research
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[Presentation] Geologic and petrologic study of the Kamo monogenetic volcanic field, Southern Kyushu, Japan2019
Author(s)
Nche, L.A., Hasegawa, T., Kobayashi, T., Nemeth K., Aka, F.T.
Organizer
JpGU meeting
Related Report
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[Presentation] Petrographic and geochemical characteristics of Kamo monogenetic volcanic group (Southern Kyushu, Japan)2019
Author(s)
Nche, L.A., Hasegawa, T., Aka, F.T., Kobayashi, T., Nemeth, K.
Organizer
IAVCEI 5th Volcaic geology workshop
Related Report
Int'l Joint Research
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