Research Project
Grant-in-Aid for Scientific Research (C)
We performed petrologic study on eruption products of the Goshikitake, the newest edifice of Zao volcano, and obtained following results. (1) By examining whole rock and mineral chemistry, couple with mineral texture, we revealed the shallow magma chamber located ca. 6 km depth and was rather heterogeneous. (2) The diffusion calculations based on chemical zoning of orthopyroxene phenocrysts indicated that the longest residence time of the phenocrysts in the chamber after the injection of deeper mafic magmas was more than ca. 50 years and most frequently one was less than several years. (3) Sr isotopic analyses revealed eruption products from Okama crater has different origin from the other eruption products of Goshikidake.
浅部マグマ溜りの詳細構造と噴火に至るタイムスケール解明を、噴出物の組織解析と各種化学組成分析を組み合わせて行ったことが特色であり意義が深いと考えられる。また、噴火が危ぶまれる火山について、噴火以前に物質科学的解析を行い、観測から得られる情報と融合させてその火山の状態把握と今後の推移について予測しようとする試みは学際的な貢献という点で意義があると考えられる。本研究によって浅部マグマ溜りの詳細構造や噴火に至るタイムスケール及び地下で進行している現象もある程度推定された。これは現在火山研究で喫緊に行うべきと社会から要請されている噴火予測や噴火発生場の解明に関して大きな貢献となったと考えられる。
All 2019 2018 2017 Other
All Int'l Joint Research (1 results) Journal Article (4 results) (of which Int'l Joint Research: 2 results, Peer Reviewed: 4 results, Open Access: 3 results) Presentation (16 results) (of which Int'l Joint Research: 4 results) Book (1 results) Remarks (3 results)
火山
Volume: 64 Pages: 131-138
130007676210
Journal of Volcanology and Geothermal Research
Volume: 371 Pages: 137-161
10.1016/j.jvolgeores.2019.01.003
Volcanoes, InTech
Volume: -
Chemical Geology
Volume: 480 Pages: 28-34
10.1016/j.chemgeo.2017.05.013
http://yudb.kj.yamagata-u.ac.jp/html/631_ja.html
https://researchmap.jp/read0169359
http://ksgeo.kj.yamagata-u.ac.jp/laboratories-j.html