We tested an intact sample from Borehole C0002T, recovered from the inner accretionary prism at the Nankai Trough, at estimated in-situ effective stress conditions in a laboratory friction experiment to measure its strength and frictional characteristics. We use inverse modeling within the rate-and-state dependent friction framework to extract parameters used to calculate various estimates of the critical patch length for frictional instability. This study reports new analyses in addition to those reported from the same sample by Okuda et al., 2021.