It is important to clarify the structure and constituent minerals of a fault zone in order to evaluate fault activity. Thus, we conducted a detailed structural analysis of a fault zone of the Yamada fault, observed in a granite outcrop, to understand the characteristics of active and inactive faults during the Quaternary.

The fault zone consisted of fault gouge zone, fault breccia, and cataclasite, and included a main fault plane and several minor fault planes. The main fault plane cut unconsolidated sediment layers and was associated with the fault gouge zone. The fault gouge zone exhibited a layered structure with 10 fault gouge layers characterized by composite planar fabrics indicating dextral slip and composed mainly of smectite. Thus, we infer that the gouge zone was formed after smectite crystallization by repetitive slip in the shallow part of the crust. The minor fault planes showed no clear relationship with the unconsolidated sediment layers in the outcrop; further, they were not associated with fault gouge, and were in direct contact with the cataclasite. Within the cataclasite, biotite that had been plastically deformed in the deep part of crust was recognized, and no structures indicating fault activity in the shallow part of crust were observed. Thus, we infer that the minor fault planes have been inactive during the Quaternary.

Mode of occurrence and distribution of fractures are described on a boring core drilled in non-weathered serpentinite, exposed at the Ube coastal area, Yamaguchi Prefecture. The fracture tends to form a zone, named the fracture zone, composed of several fractures on the borehole fracture column. In the case of the Ube serpentinite body, a fracture zone includes 5～20 fractures and the mean fracture spacing is around 20～40 ㎜. The deformation modulus obtained by pressure meter test in the borehole ranges 30～500MPa, however, the re-calculated value of deformation modulus corresponding to the most fracture zone concentrates within 30 to 40MPa. This value is ca. 1/10 of the non-fractured part, which gives the mean deformation modulus of fracture zones （weakened parts） of serpentinite.

To investigate differences on permeability and three dimensional void geometry in two sandstones, permeability evolution by increasing confining pressure was measured and its relationship to three dimensional geometrical information was analyzed with micro focus X-Ray CT. In this research, Berea sandstone and Otway sandstone were used as a specimen, and their total porosity measured by Mercury Intrusion Porosimetry were 18% and 25%, respectively. Pore size distribution of both sandstones was an unimodal manner, but that of Otway sandstone showed slightly narrower peak around 5～7μm. Permeability in both sandstones decreased with increasing effective confining pressure, but its absolute value of Otway sandstone was lower by one order of magnitude than that of Berea sandstone. Three dimensional medial axis method was adopted to compare pore geometry in two sandstones. Several geometrical information was obtained such as pore and throat radius, pore coordination number, tortuosity, number of connecting path, connecting path volume and so on. Otway sandstone was characterized as a large frequency in effective throat/pore radius ratio. In fluid flow mechanism, the larger number of effective throat/pore radius ratio exists in sandstone specimen, the more fluid pressure potential consume. There is some possibility that the magnitude of the radius ratio with adjacent voids governs permeability of sandstone.