Its capability, however, in rock engineering has not been clarified sufficiently, that is, a constructed tomographic image docs not help our understanding on joint characteristics by itself. It is because the propagation velocity of a seismic wave remains being as an overall index of the dynamic behaviour of a rock mass without clarifying any characteristics of rock mass. The first author initiated the study on the relationship between seismic behaviour and mechanical properties of jointed rock in association with the research for the magnitude of loosening event during the construction of the long suspension bridge in late 1970s [Tanimoto & Ikeda, 1983J. Our experimental study in laboratory on seismic behaviour has been carried out with respect to joint orientation, joint frequency, aperture, roughness, infilling material, alteration, moisture content, etc. under normal and shear stresses [Tanimoto, et aI., 1994a]. To speak of the representation of joint roughness, Barton's JRC has been conveniently employed, but the determination of a JRC-value has to be estimated with referential profiles given by Barton et al. [Barton, et aI., 1977].