日本地球惑星科学連合2023年大会

講演情報

[E] 口頭発表

セッション記号 S (固体地球科学) » S-GC 固体地球化学

[S-GC37] Volatiles in the Earth - from Surface to Deep Mantle

2023年5月23日(火) 13:45 〜 15:00 303 (幕張メッセ国際会議場)

コンビーナ:羽生 毅(海洋研究開発機構 海域地震火山部門)、Tomonaga Yama(University of Basel)、角野 浩史(東京大学先端科学技術研究センター)、佐野 有司(高知大学海洋コア総合研究センター)、座長:Tomonaga Yama(University of Basel)、角野 浩史(東京大学先端科学技術研究センター)

14:30 〜 14:45

[SGC37-04] Monitoring dissolved gases in thermal water to assess the potential relation between fluid geochemistry and seismicity

★Invited Papers

*Sebastien Giroud1,2Yama Tomonaga1,4、Matthias Brennwald1、Rolf Kipfer1,2,3 (1.Dept. of Water Resources and Drinking Water, Eawag、2.Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich、3.Institute of Geochemistry and Petrology, ETH Zurich、4.Dept. of Environmental Sciences, University of Basel)

キーワード:seismicity, noble gases, geochemical changes

The relationship between dissolved gas concentrations in geological fluids and seismic activity is a topic of ongoing debate. While there have been several examples of correlations between changes in gas composition and seismicity, these are often based on observations of single events. Moreover, data from long-term systematic gas monitoring are hardly available. This leads to the difficulty and complexity of determining the causality between earthquakes and evolution of gas dynamics [1].

To address this issue, we deployed a portable gas equilibrium membrane-inlet mass spectrometer (miniRUEDI, [2]) at the hot springs of Lavey-les-Bains located in a seismically active region of Switzerland (range of geothermal fluids: 50 °C – 65 °C). This instrument provided high-frequency and long-term time-series of dissolved gas concentrations (e.g., He, Ar, Kr, N2, O2, H2, CH4 and CO2), including data from over a year-long period. These data set the experimental basis to critically assess if gas evolution in geological fluids and seismicity are causally linked.

[1] Toutain et Baubron (1999), Tectonophysics, 304, 1-27
[2] Brennwald et al. (2016), ES&T, 50, 13455-13463