Discrimination between active and non-active faults in Kojyaku granite based on the chemical composition of the fault gouge

Tateishi, Ryo*; Shimada, Koji   ; Iwamori, Akiyuki*; Ogita, Yasuhiro  ; Wada, Shinya*; Kunimatsu, Wataru*; Otsuka, Yoshiharu*

It has been demonstrated that active faults (strike-slip faults) and non-active faults developed in granitic rocks in Japan can be discriminated with high probability by linear discriminant analysis using chemical compositions of fault gouge samples. Although, the result included that a reverse fault type active fault was discriminated on the inactive fault side. In this study, to confirm whether this result is due to the difference in fault type or the difference in rock body, chemical composition and linear discriminant analysis of the fault gouge of active reverse faults, active strike-slip faults, and non-active faults in the Kojyaku granite were carried out. As a result, the discrimination rate between active and inactive faults was 100% for 13 (chemical) components and 7 components selected by AIC, and 90% for 3 components. This result suggests the possibility that the difference in the granite bodies affected the discrimination more than the difference of their fault type.