JpGU-AGU Joint Meeting 2017

Presentation information

[JJ] Oral

S (Solid Earth Sciences) » S-SS Seismology

[S-SS17] [JJ] Fault Rheology and Earthquake Physics

Sat. May 20, 2017 1:45 PM - 3:15 PM A09 (Tokyo Bay Makuhari Hall)

convener:Takanori Matsuzawa(National Research Institute for Earth Science and Disaster Resilience), Takeshi Iinuma(National Research and Development Agency Japan Agency for Marine-Earth Science and Technology), 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), Chairperson:Takeshi Iinuma(National Research and Development Agency Japan Agency for Marine-Earth Science and Technology), Chairperson:Tetsuro Hirono(Department of Earth and Space Science, Graduate School of Science, Osaka University)

2:00 PM - 2:15 PM

[SSS17-08] Mechanochemical effects on maturation of carbonaceous materials in faults during earthquakes

*Ichiba Tatsuya1, Shunya Kaneki1, Tetsuro Hirono1, Kiyokazu Oohashi2 (1.Osaka University Graduate School of Science, 2.Yamaguchi University Faculty of Science Department of Geosphere Sciences)

Keywords:Fault, Carbonaceous materials, Spectroscopic analysis

Frictional heating is thought to occur during an earthquake and the shear stress can be estimated from the temperature recorded in the fault. A new temperature proxy for maturity of carbonaceous materials by using infrared and Raman spectroscopies was recently proposed, but intra-crystal change by shear damage may affect on the maturation. Here we focus on the mechanochemical effect in the process by performing low-velocity friction experiment and spectroscopic analyses.

We performed the friction experiments at 3.0 MPa normal stress and 1 mm/s slip rate, and 10 m slip distance by using the mixture of 90 wt.% quartz and 10 wt.% coal. To reproduce heating during earthquake slip, we heated the samples after experiments at 100-1000 °C. By comparing the spectra on these samples, we confirmed that some reactions, such as breakage of aliphatic chain, occurred at relatively low temperature on sheared samples. Thus, the mechanochemical effect should be considered for deterring the temperature recorded on the basis of the maturation.