Japan Geoscience Union Meeting 2015

Presentation information

Oral

Symbol S (Solid Earth Sciences) » S-SS Seismology

[S-SS29] Fault Rheology and Earthquake Dynamics

Sun. May 24, 2015 12:00 PM - 12:45 PM A05 (APA HOTEL&RESORT TOKYO BAY MAKUHARI)

Convener:*Wataru Tanikawa(Japan Agency for Marine-Earth Science and Technology, Kochi Instutute for Core Sample Research), Takeshi Iinuma(International Research Institute of Disaster Science, Tohoku University), Yuta Mitsui(Department of Geosciences, Graduate School of Science, Shizuoka University), Hideki Mukoyoshi(Department of Geoscience Interdisciplinary Graduate School of Science and Engineering, Shimane University), Chair:Wataru Tanikawa(Japan Agency for Marine-Earth Science and Technology, Kochi Instutute for Core Sample Research), Hideki Mukoyoshi(Department of Geoscience Interdisciplinary Graduate School of Science and Engineering, Shimane University)

12:15 PM - 12:30 PM

[SSS29-02] Blackening of fault gouge by pyrolysis of carbonaceous mineral

*Shunya KANEKI1, Tetsuro HIRONO1 (1.Department of Earth and Space Science, Graduate School of Science, Osaka University)

Keywords:carbonaceous material, pyrolysis, frictional heating, fault gouge

Earthquake slip induces frictional heating and comminution of mineral grains on the fault and interseismic physicochemical process produces the fault gouge. The fault gouges sometimes exhibit various colors (white-pink-green-gray-black), and in particular those developed in sedimentary rocks show gray to black. However, the origin of the change in color was not fully understood, and its relationship to slip parameters such as friction work and heat was not also revealed. Therefore, in this study, we focus on the blackening of the fault gouge originated from the sedimentary rocks. We first performed frictional and milling experiments on the mixture samples of clay mineral (montmorillonite) and coal (bitumen), and then investigated the spectroscopic feature by using visible, infrared, and Raman spectroscopies. We recognized blacker sample after friction experiment with higher initial content of coal, and confirmed the Raman G and D bands on the surface of clay mineral. Thus, we inferred that frictional heating induced thermal decomposition of carbonaceous material and the pyrolytic gases adsorbed on the surface of mineral grains resulting in the blackening. Furthermore, black-fault gouges in natural might have experienced high temperature at > 300 ℃.