Tribochemical hydrogen generation process associated with high-velocity frictional slip of faults

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01185
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 17040:Solid earth sciences-related
• Research Institution: Okayama University (2023); Hokkaido University (2021-2022)
• Principal Investigator: Kameda Jun 岡山大学, 惑星物質研究所, 教授 (40568713)
• Co-Investigator(Kenkyū-buntansha): 鈴木 徳行 北海道大学, 理学研究院, 名誉教授 (00144692) ; 廣瀬 丈洋 国立研究開発法人海洋研究開発機構, 超先鋭研究開発部門(高知コア研究所), 研究所長 (40470124)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: トライボケミカル反応 / 水ー岩石反応 / 水素 / 断層 / メタネーション

Outline of Final Research Achievements

In this study, gas-production reactions that proceed in a fault during earthquake occurrence and the migration and storage processes of the gases produced were investigated by residual gas analysis and nanopore analysis of fault rocks formed in various geological environments. As a result, we found traces of H2 formation reactions at high temperatures above 250°C and traces suggesting methane conversion of CO2 in faults composed of igneous rocks. The nanopores in fault rocks are thought to be blocked by mineral precipitation at high temperatures around 200°C, while at low temperatures they are enlarged by rock fracturing and facilitate gas migration. In particular, gases formed in faults at temperatures below 200°C may diffuse efficiently into the surrounding and shallow subsurface areas of the fault, affecting the formation of resources and microbial metabolism there.

Free Research Field

構造地質学

Academic Significance and Societal Importance of the Research Achievements

本研究では、地球内部の水素生成作用の中でも断層活動に関連した反応に焦点をあてた。その結果、多様な地質環境における水素やその関連ガスの生成・貯留プロセスの一端が明らかとなってきた。これらの成果は、地下ガス資源の形成機構解明につながるだけでなく、地球に学ぶ新たな水素エネルギー生成技術などにつながる重要な知見と考えられる。