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The paper presents findings of tectonic-stress field reconstruction in the central part of Sakhalin Island as a result of field tectonophysical studies between 2020 and 2022. The measurements made it possible to determine the predominant orientation of the main slickenside systems with different kinematics. The territory of Central Sakhalin is characterized by mainly subvertical orientation of the axis of maximum compression and by the subhorizontal and mostly submeridionally directed axis of minimum compression/extension. The main detected feature of Central Sakhalin is the predominance of horizontal extension as the stress state type for the entire area. Horizontal shear and compression settings are significant in its western part. The number of horizontal extension settings increases in the near-axial and eastern part of Central Sakhalin towards the Sea of Okhotsk. We found a cardinal difference between the stress field reconstruction data obtained there and the results of similar studies in other geodynamically active regions of Russia. [ABSTRACT FROM AUTHOR]

The stress state of the sedimentary rocks in the oil-and-gas fields of Sakhalin is estimated and analyzed; data from exploratory boreholes in the eastern Pacific (San-Andreas fault zone) are considered. The vertical and limiting horizontal stresses are calculated for different depths. The maximum sublateral compression can exceed the vertical stress by a factor of 1.2-4 on average in northern and southern Sakhalin. It is shown that the limiting horizontal stress and the maximum shear stress grow as the depth increases. [ABSTRACT FROM AUTHOR]