Neotectonic Vertical Movements in the South Sikhote-Alin and Characteristics of Self-Similarity of the Stream Network in the Region

A morphostructural analysis of the relief and fractal analysis of the stream network of the South Sikhote-Alin orogenic belt were carried out. The formation of the relief at the neotectonic period occurred in several stages, which was reflected in the stream network pattern: (1) during pre-Oligocene time there was a general uplift of Sikhote-Alin; (2) activation of vertical neotectonic movements occurred in the Pliocene, which were most intense to the East of the Central Sikhote-Alin Fault and were synchronous with basaltic volcanism; (3) in the Pleistocene, vertical movements of significant amplitude did not occur; at this time, the modern erosion–denudation relief typical of the studied region was formed; and (4) at the end of the Pleistocene and in the Holocene a slight activation of vertical neotectonic movements to the East of the Central Sikhote-Alin Fault occurred, which was reflected in the residual relief peculiarities. Comparison of the morphostructural and fractal analyses showed that the maxima of the PRNS complex parameter of self-similarity are consistent with the areas of greatest increments in elevation and the minima are consistent with the areas of the smallest increment of relief or with the areas of most significant erosion. In the regions with a stage character of neotectonic evolution, the fractal analysis of the stream network should involve additional factors controlled by the peculiarities of the stream network evolution at each stage of the evolution, as well as by the conservative nature of its pattern, which reflect the features of the evolution of the relief at different stages.