2019 Fiscal Year Final Research Report
Physical state of hydrothermal system to understand the mechanism of phreatic eruption
Project/Area Number |
19K21058
|
Project/Area Number (Other) |
18H05877 (2018)
|
Research Category |
Grant-in-Aid for Research Activity Start-up
|
Allocation Type | Multi-year Fund (2019) Single-year Grants (2018) |
Review Section |
0204:Astronomy, earth and planetary science, and related fields
|
Research Institution | National Institute of Advanced Industrial Science and Technology |
Principal Investigator |
Seki Kaori 国立研究開発法人産業技術総合研究所, 地質調査総合センター, 研究員 (90828047)
|
Project Period (FY) |
2018-08-24 – 2020-03-31
|
Keywords | 水蒸気噴火 / 熱水系 / 火山ガス / 温泉水 / 箱根大涌谷 / 立山地獄谷 |
Outline of Final Research Achievements |
Phreatic eruption is one of the volcanic eruption style. Although phreatic eruption often occur in the world, the mechanism of phreatic eruption is not clear because of the small scale. In this study, I measured chemical and isotopic composition of hot-springs and fumarolic gases sampled at Owakudani in Hakone Volcano and Jigokudani Valley in Tateyama Volcano that have the potential of the phreatic eruptions. The temperature of the hydrothermal system beneath Owakudani was estimated to be less than 260 degrees. The temporary change of the chemical composition of the fumarolic gases were observed, which was estimated to be associated to the increased volcanic activity. Some fumarolic gases in the Jigokudani Valley was affected by isotopic fractionation at temperature of 100 degrees, and the others are separated from magmatic water and meteoric water at higher temperature. The hot-springs are classified into three types by the ratio of Cl and SO4.
|
Free Research Field |
火山学
|
Academic Significance and Societal Importance of the Research Achievements |
水蒸気噴火は,国内でも数多く発生し,噴火頻度そのものは多いにも拘らず,その噴火規模が小さいため,発生機構は明らかになっていない.水蒸気噴火が発生しうる火山は,観光地となっている場合が多く,小規模な噴火であっても,深刻な自然災害となりうる.本研究では,水蒸気噴火が発生しうる火山において,火山ガスおよび温泉水の採取を行い,水蒸気噴火の発生場として考えられている,熱水系の構造を明らかにし,火山活動の評価を行ってきた.
|