A.A. GAVRILOV
4th International conference on Asian Marine geology. Qingdao. 1999. Abstracts. P. 34

The comparative investigation of rose-diagrams and the network of fracture zones of Sikhote-Alin, the Korean Peninsula, Sakhalin and the group of Japanese islands has been conducted. The initial data were received as a result of decipherment of black-white remote sensing pictures with a scale of 1-1.5 million and processing of geological and geophysical maps information of different scales. The coefficients of pair correlation (CPC) for fault systems of Honshu and other islands and continental parts of the Sea of Japan region were revealed to be 0.54 for the Shikoku island, 0.36 for Kyushu island, 0.39 for the Korean Peninsula, 0.41 for Sikhote-Alin (Fig 6).

This indicates the principal similarity of the Phanerozoic stress field and network of fracture zones of the land parts located around the Japan Sea and the absence of large horizontal movements of tectonics blocks. But CPC between Honshu and Hokkaido islands fault systems is only-0,07. The rose-diagram of faults of the Honshu island and Lower Amur (CPC -0,31), Honshu and Sakhalin islands (CPC -0,11) are also very different. The main reason for these distinctions is a presence of large transregional lineaments, which determine a predominance of orientations of local systems of disjunct dislocations within considerable areas. These transregional structures stretch over thousand kilometers pre-determining also the Japan Sea-line configuration. The east and southeast margins of the Japan Sea basin adjoin fault zones, which are the fragments of the Ryukyu - Kuril transregional lineament. There is a group of large faults of the northwest direction (Geol. map, 1984) within the northeast part of the Korean Peninsula. These dislocations are considered to be the extension of the oceanic Palau-Kyusyu ridge lineament. The systems of transregional faults of the northeast (Ussuro-Rasdolnenskaja) and latitudinal (South-Primorskaja) strikes cause all peculiarities of shoreline configuration of the west and northwest of the Japan .Sea. There are some northwest, latitudinal and other faults systems, which pass throughout the Japan Sea basin. But the south borders of the Japan Sea are connected with a large latitudinal zone with the northwest orientation (Az.str.280 degrees) within Korea and northeast strike (Az. 80 degrees) in the southern Honshu. The arched dislocations system can be explained by the following: 1) a displacement of the southeast part of the Honshu block structure to the north for about 100 km; 2) spreading process between the Korean Peninsula and the Honshu island as a result of a slip of the Honshu block to the east: 3) appearance of ring and arched faults, connected with the formation of mantle diapir and ring rift, taphrogenic zones around the Yamato Rise. These data exclude the possibility of realization of large (many hundreds kilometers) horizontal movements within the limits of the Japan Sea region and shows predominance of taphrogenic processes. The circular form and radial-concentric zonality of geomorphological and geological elements and the existence of hard tectonics borders emphasize homology between the Japan Sea and Sea of Okhotsk basins and the similarity of mechanisms of their formation and development. The marginal seas of the east marches of Eurasian continent mark out the global taphrogenic zone with separate mantle diapirs.

Keywords: fault, lineament, fracture zone, the Japan Sea region