Estimation of fault activity by linear discriminant analysis using chemical composition of fault gouge

Tateishi, Ryo*; Shimada, Koji   ; Shimizu, Mayuko   ; Sueoka, Shigeru   ; Niwa, Masakazu   ; Ishimaru, Tsuneari 

The identification of active faults is based on the displacement and deformation of the current topography and the late Quaternary strata. However, in the absence of them, it is difficult to determine the fault activity. To solve this problem, multivariate analysis was performed using chemical composition data of fault gouges of active and inactive faults in Japan. We performed linear discriminant analysis with a following combination of elements; (a) 11 elements selected by AIC, (b) 8 elements with p-value between 0 and 0.01, (c) 6 elements with p-value between 0 and 0.001. The discrimination rate between active faults and inactive faults is 100% in (a), (b) and 97% in (c). Among elements that represent the difference, TiO and PO, and AlO and Rb are considered important, including their respective combinations. These results contribute to clarify the mechanism that creates the difference in chemical composition between active and inactive faults.