**6. The OSC area in the northeast Transbaikalia**

The area situates in the territory of Zabaikalian Krai, south Yakutsk, and northwest of the Amurian District between the Vitim River and upper stream of the Aldan River (**Figure 5**). Its length is 464 km, width – 64-108 km, and the total seismic energy reaches 4.64153·1016J, that is nearly equally to the energy of the OSC area of the north Pamir - 4.50343·1016J [24]. The energy level oscillates on the regarded area between 104 - 1012J and M in epicenters changes from 3 up to 6. M of separate events reaches 6–7. Northeast normal faults with the left-lateral slip component predominate in the west of the OSC area and northwest left-lateral slips develop in the east. Tectonic stress axis's have the stead northeast direction.

#### **Figure 5.**

*The OSC area in northeast Transbaikalia settles down within the seismic active interblock zone between NEP and the Amurian block. See summary legend for the Figure 1.*

According measuring at the Yakutsk Station NEP moves on 121° SE with velocity 20.0 mm/y, but simultaneously displaces south relatively the stable Eurasia in the NNR\_NUVEL\_1A System. Azimuths of the vast Amurian Block change from 106° SE on the Ulan-Bator Station up to 110° near Beijing with velocities 29-32 mm/y. This block turns counter-clockwise after SLR and GPS data 2000–2008 coinciding with right-lateral displacing along the large-scale Tanlu Slip System on the block east boundary. The same turn fixed by results of the Belgic-Russia tidal gravitation profile along 50° N latitude [25, 26]. The alternation of wide northeast strips with +100 - -100*n* takes place in the magnetic field above the Amurian Block. They apparently can reflect the early Precambrian block fundament structures strike. After seismic tomographic data, the reduced lithosphere thickness characterizes the north part of the block (100-105 km in comparison with 200 km under NEP) [27]. The low values of the rock density and electric resistance apparently correspond to lithosphere deep stratification on boundaries of 10, 20, 40 and 70-90 km [28].

Low *Pn*-waves velocities characterize the upper mantle under the transitional zone between continent and ocean under Amurian and neighboring Japanese-Korean blocks [22]. Some researches suppose existing of the strong upper mantle substance flow on the southeast direction based on the analysis of lengthening deformation axis's and anisotropy in border fields of NEP and Amurian Block. This deep flow causes the NEP clockwise turn confirmed by ITRF2014 vectors [23]. The above-mentioned simultaneous counter-clockwise turn of the Amurian Block apparently results in opening the Baikal Rift. At the same time, we cannot exclude the influence of plume tectonic processes on geodynamics of the Amurian Block – NEP zone. After seismic tomography data isometric counters of S-waves' velocity slowing-down projections (see **Figure 3**) up to ≤4.2–4.25 km/sec−1 take places on 50, 100, 150, 200, 250, and 300 km depth levels [16]. Note that the majority of the high heat-flow meanings up to 64-100 μW/m−2 coincide with S-waves velocity slowingdown projections [8]. These data allow supposing ascent of heating and non-consolidated mantle material to the earth's surface with increasing seismicity level.

Speaking on the future seismic events it is needed to distinguished the east part of the regarded OSC area on Olekma River booth banks in the region of BAM railway stations of Khani and Yuktali as well as east up to left bank of the Upper Aldan River. There it is possible to wait for new earthquakes with M up to 7–8. In the other area territory M most likely will be not higher than 6. The light hypocenters concentrations coincide with depths of 10–11 and 21-26 km.
