## 3 Results
Samples 55-3, 59-1, 59-2, 60-1, 60-2, 60-3, 81-3 and 81-4 have predominantly northeastern orientation of microfractures. In samples 55-1 and 81-5, the microfractures are developed along the latitude with slight deviations to the northwest and northeast, respectively. Predominant northwestern orientations were identified in thin sections 55-4 and 58-1; a less pronounced northeastern orientation is also distinguished here. Samples 56-1 and 57-1 show north-northeastern orientations of microfractures. In the sample 61-5, microfractures are oriented almost uniformly in all directions. A comparison of petrographic analysis data to the results of STMA reveals a high correlation. Thus, it was possible to identify clusters that characterize the heterogeneity of the fault zone. Four clusters were identified (Figure 10). Cluster I shows the highest permeability. It includes samples of amphibolites, amphibolite schists and gabbro, which, by the type of tectonic, belong to cataclasites and blastocataclasites. Predominantly brittle deformations manifest in this area. Cluster II shows lower permeability, which corresponds to host rocks represented by leucocratic granite guesses. Brittle deformations also prevail here. Figure 10: Integration of the data of petrographic and microstructural analyses of rock samples collected across the Primorsky Fault. Cluster III was identified via only a single gneissose granite sample. It shows less pronounced brittle deformations, and it is a blastocataclasite according to the type of tectonic. The identification of this cluster is in doubt. Cluster IV is represented by shales of different mineral composition and, to a lesser extent, by transformed plagiogranites. Cluster IV characterizes the transition from brittle to ductile deformations; it mainly includes mylonites and blastolynolites. Moreover, this cluster coincides with the zone of stress metamorphism established via petrographic analysis. In order to characterize the fault zone, it is important to understand the change in the main quantitative characteristics of microfractures with distance from the fault trace (Figure 11). The total length and number of microstructures naturally increase with distance from the fault trace (Figure 11A). At the same time, a local maximum is fixed in the interval of 400-500 m, which was established in one sample (57-1). The distributions of L/S ratios and fracture intensity (N/L) show heterogeneous distribution (Figure 11B). In the immediate vicinity of the fault trace, the L/S values are in the range of 0.043-0.120. At a distance of more than 400 m from the fault trace, the values vary from 0.110 to 0.150. The fracture intensity near the fault trace varies in a wide range--from 0.033 to 0.039. Then, the values decrease linearly again to 0.033 with distance. It should be noted that all values of the N/L parameter are generally in a very narrow range. The porosity and permeability show a similar trend (Figure 11C). They are characterized by the lowest values near the fault trace (up to 200 m) and increase with distance from 400 to 1100 m. The maxima are reached at a distance of more than 1200 m.  
Figure 11: Graphs of the distribution of cumulative length versus number of microfractures (**A**), L/S versus N/L (**B**), permeability versus porosity (**C**) with distance from the fault trace.