Japan Geoscience Union Meeting 2025

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[J] Oral

S (Solid Earth Sciences ) » S-SS Seismology

[S-SS10] Fault Rheology and Earthquake Physics

Fri. May 30, 2025 1:45 PM - 3:15 PM Exhibition Hall Special Setting (3) (Exhibition Hall 7&8, Makuhari Messe)

convener:Ritsuya Shibata(National Research Institute for Earth Science and Disaster Resilience), Michiyo Sawai(Chiba University), Hanaya Okuda(Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology), Kenichi Tsuda(Institute of Technology, Shimizu Corporation), Chairperson:Hanaya Okuda(Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology), Michiyo Sawai(Chiba University)

2:15 PM - 2:30 PM

[SSS10-19] Graphene Oxide in the Fault Gouge of the Atotsugawa Fault System: Relationship of Fault Movement and Redox Reactions

*Tomoya Shimada1, Hiroyuki Nagahama1, Jun Muto1, Norihiro Nakamura2 (1.Graduate School of Science, Department of Earth Science, Tohoku University, 2.Tohoku Gakuin University)


Keywords:Graphene oxide, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Redox reactions, Fault movement

The Atotsugawa Fault System in central Japan exhibits low seismic activity to depth of 7-8 km. Low-friction graphite (μ ~0.1) is believed to reduce fault strength and contribute to this peculiar seismicity (Oohashi et al., 2012). This study focuses on graphene oxide, derived from the oxidation and exfoliation of graphite. Graphene oxide exhibits a very low friction coefficient of approximately 0.01 (Bouchet et al., 2017); therefore, it can reduce the fault strength more effectively than graphite. We discovered graphene oxide for the first time in the fault gouge of the Atotsugawa Fault System, using Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Both spectroscopies identified the presence, chemical state and distribution of graphene oxide in the fault gouge and surrounding Tetori Groups. Although small amounts of graphene oxide were partially confirmed in the Tetori Groups, most graphene oxide was concentrated along cracks within the fault gouge, promoting fault slip and influencing frictional properties. Raman spectroscopy revealed that the fault gouge exhibited a lower intensity ratio (ID/IG) compared to rocks from the Tetori Groups, suggesting that this change was induced by strain accumulation during fault movement. Additionally, in each fault gouge, smaller D'inf − Gapp correlated with higher ID/IG. The D'inf − Gapp decreases with oxidation and correlates with the carbon-to-oxygen (C/O) ratio (King et al., 2016). Therefore, the degree of oxidation in carbonaceous materials within the fault gouge correlates with the intensity ratio, indicating a relationship between fault motion and redox reactions. In this presentation, we discuss the relationship between fault movement and redox reactions in the Atotsugawa Fault System and further consider the formation process and origin of graphene oxide.