[1] Fractures play a vital role in fluid flow through rocks, and highly fractured zones can be the most permeable part of a fault zone. However, the evaluation of the hydraulic properties of natural fractured rocks at great depths is not easy because of the complexity of fracture geometry and the scaling problem from laboratory to nature. As a first step toward the estimation of flow rate through fractured zones at depth, this paper examines the issue of permeability estimation in the case of flow between polished surfaces of known topography (or roughness) via an integrated study of permeability measurements at effective pressures up to 180 MPa, surface roughness measurements, and contact analyses using the Hertzian theory of surface asperities of fractures as a function of stress. Apertures between two polished surfaces in specimens of Sambagawa pelitic schist and Ryoke mylonite were estimated from permeability measurements assuming the cubic law. The aperture of contacting surfaces has also been calculated from contact analyses of representative asperities. Despite some imperfections in the agreement between these two approaches, the overall features of progressive reduction in aperture upon an increase in effective pressure were successfully predicted. Deviations between the two approaches are probably due to complex deformation of multiple contacting asperities or limitations of our contact analysis method.Citation: Uehara, S., and T. Shimamoto (2009), Contact analyses and permeability measurements of polished fracture surfaces in Sambagawa metapelitic schists and Ryoke mylonites from the Median Tectonic Line, Japan,