The mechanical and hydrological properties in a rock mass are strongly affected by the innumerable geological discontinuities on several scales including joints, faults, fissures. Calling such discontinuities fractures together, the fracture investigations are one of the most important means for the rock mass characterization. In general, only the directions (strike and dip) of fractures are considered in the engineering analysis of rock mass, although each fractures have their own mineralogical and geometrical properties, e.g., the degree of alteration, the geometrical shapes appearing on the rock surface, the roughness of fracture surface, the kinds of filling materials and so on. It is considered that those various qualities of fractures are closely associated with the heterogenity and anisotropy of the mechanical and hydrological characteristics of rock mass. Therefore, each fracture must be investigated in detail from the viewpoint of mineralogy and engineering geology, and such vast quantity of investigation data must be systematically stored as a datafile and efficiently analyzed using a computer.
For this purpose, we have constructed a “Fracture Database System” which consists of the field investigation data for each fractures and retrieval system for multi-dimensional characteristics of fractures from the datafile. The system is applied to the results of about two thousands fracture measurements for 16 items in the two drifts of the Kamaishi mine associated with the granitic massif. By application of this database system, following results are obtained:
(1) Though the lithology of the study area consists of a granodiorite called Kurihashi massif and a diorite called Ganidake massif, the fracture properties related to the mechanical condition for the fracture development, e.g., the direction, the geometrical shape, and the roughness of frature surface are similar to each massif. On the other hand, the degree and color of alteration around fractures, the kind of materials with which the chink in fracture is filled are different from the two massifs according to their lithology.
(2) The fractures whose width of alteration and width of filling materials are relatively large are develop-ing at the rock mass in the drift sections with large amount of seepage. In addition, the appearance frequency of chlorite as a filling material tends to be higher than calcite in those sections.

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As a part of the Sequential Machine Interpreted Lineament Extraction System (SMILES : Raghavanet al., 1993b, c), a subroutine for generating shaded relief image from digital elevation data is presented. The Automatic Relief Image Enhancement and Shading (ARIES) subroutine uses a simple Lambertian reflection model, wherein the direction of the illumination source is controlled by the user. In addition, the ARIES also incorporates routines for generating three dimensional terrain model by combining elevation data and digital images. Shaded relief images have been used for automatic extraction of lineament information. Further, it is suggested that the combination of digital elevation data and digital images may help simulate aerial reconnaissance and aid in ground verification of lineaments. The application results for a test site in southwestern Japan is described.

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