This paper considers the geological structure, geodynamics, and seismicity of the Tan Lu-Okhotsk rift system, which includes the Bohai Wan, Liaohe, Khanka, Middle Amur, and Lower Amur basins. The basins have common regularities typical of rift zones but differ in the deep structure and physical parameters of their crust, in particular, in the distribution of the strength properties, which also affect the seismicity level. It was established that the level and type of seismicity in the rift system is mainly determined by the local geodynamic conditions.

Small coseismic offsets detectable using GPS techniques were found more than 2300 km away from the Great Tohoku 2011 earthquake epicenter. Area of the most intense far-field co- and postseismic deformations with the maximum offset values exceeding 40 and 18 mm, respectively, extends westward from Honshu Island to the Korean Peninsula, northeastern China and southern Far East Russia. Sakhalin Island does not exhibit notable displacements caused by the earthquake, in contrast to the adjacent territories. A rectangular fault model with uniform slip was developed based on the GPS-detected far-field coseismic displacements using the spherically layered Earth assumption. Both far- and near-field coseismic deformations are generally well described by a single-segment rupture of 200 × 96 km2, characterized by thrust slip with minor strike-slip component of about 33 m and by the seismic moment value of 1.9·1022 N·m (Mw = 8.8), which roughly constrains the major slip area. The resultant compact fault geometry revealed that the main portion of the seismic moment had been realized in a relatively small-sized rupture segment. The sensitivity of far-field GPS data to the major slip area might also be used in the development of a seismically generated giant tsunami warning system.

The present tectonics of Northeast Asia has been extensively investigated during the last 12 yr by using GPS techniques. Nevertheless, crustal velocity field of the southeast of Russia near the northeastern boundaries of the hypothesized Amurian microplate has not been defined yet. The GPS data collected between 1997 February and 2009 April at sites of the regional geodynamic network were used to estimate the recent geodynamic activity of this area. The calculated GPS velocities indicate almost internal (between network sites) and external (with respect to the Eurasian tectonic plate) stability of the investigated region. We have not found clear evidences of any notable present-day tectonic activity of the Central Sikhote-Alin Fault as a whole. This fault is the main tectonic unit that determines the geological structure of the investigated region. The obtained results speak in favour of the existence of a few separate blocks and a more sophisticated structure of the proposed Amurian microplate in comparison with an indivisible plate approach.

The paper presents the data on tectonic setting, earthquake focal mechanism and parameters of the Great Tohoku Earthquake (northeast Honshu, Japan) of March 11, 2011. The waveforms of the Tohoku Earthquake and plots of average daily variations of GPS site coordinates recorded at separate sites of the FEB RAS network of deformation and seismological observations are represented. The coseismic displacements of GPS sites deployed in Priamurye, Primorye and Sakhalin areas have been calculated from the results of measurements. It has been shown that the Tohoku Earthquake appeared to be the cause of significant deformations of the crust in a huge area including regions of North-East China, Southern Priamurye and Primorye. In the continental part of the Far East, the maximum values of coseismic displacements (of about 4 cm) have been obtained for Southern Primorye decreasing northward of it.

On the relationship of peaks and troughs of the ellipticity