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V. A. San’kov A. V. Parfeevets A. V. Lukhnev A. I. Miroshnichenko S. V. Ashurkov 《Geotectonics》2011,45(5):378-393
Comprehensive analysis of the parameters characterizing contemporary and neotectonic deformations of the Earth’s crust and
upper mantle developed in the Mongolia-Siberia area is presented. The orientation of the axes of horizontal deformation in
the geodetic network from the data of GPS geodesy is accepted as an indicator of current deformations at the Earth’s surface.
At the level of the middle crust, this is the orientation of the principal axes of the stress-tensors calculated from the
mechanisms of earthquake sources. The orientation of the axes of stress-tensors reconstructed on the basis of structural data
is accepted as an indicator of Late Cenozoic deformations in the upper crust. Data on seismic anisotropy of the upper mantle
derived from published sources on the results of splitting of shear waves from remote earthquakes serve as indicators of deformation
in the mantle. It is shown that the direction of extension (minimum compression) in the studied region coincides with the
direction of anisotropy of the upper mantle, the median value of which is 310–320° NW. Seismic anisotropy is interpreted as
the ordered orientation of olivine crystals induced by strong deformation owing to the flow of mantle matter. The observed
mechanical coupling of the crust and upper mantle of the Mongolia-Siberia mobile area shows that the lithospheric mantle participated
in the formation of neotectonic structural elements and makes it possible to ascertain the main processes determining the
Late Cenozoic tectogenesis in this territory. One of the main mechanisms driving neotectonic and contemporary deformations
in the eastern part of the Mongolia-Siberia area is the long-living and large-scale flow of the upper mantle matter from the
northwest to the southeast, which induces both the movement of the northern part of the continent as a whole and the divergence
of North Eurasia and the Amur Plate with the formation of the Baikal Rift System. In the western part of the region, deformation
of the lithosphere is related to collisional compression, while in the central part, it is due to the dynamic interaction
of these two large-scale processes. 相似文献
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A. I. Miroshnichenko A. P. Sorokin V. A. San’kov A. V. Lukhnev S. V. Ashurkov A. T. Sorokina N. I. Panfilov M. A. Serov S. I. Sherman 《Russian Journal of Pacific Geology》2008,2(1):64-71
The Amur-Zeya geodynamic test ground was set up in 2000 to study recent intracontinental crustal deformations. The velocity field calculations for the period of 2000 to 2003 describe three movements scales. The general level is characterized by the vectors of IGS sites in the eastern part of Asia, the BLAG (Blagoveshchensk) site included. The southeast movement of the IRKT (Irkutsk) site of the stable Siberian Platform is indicative of deformations in the northeastern part of the Amur Plate. Measurement data on the regional near-latitudinal profile Blagoveshchensk-Sutara, which crosses the Nizhnyaya Zeya Basin, demonstrate a southwestward displacement of the Badzhal-Bureya-Lesser Khingan block relative to the North China block. The dynamic effect of the convergent boundary between the Amur and Okhotsk Sea plates is assumed to extend inland also involving the Zeya-Bureya Basin area. The measurements on the local geodynamic test site relate the deformations of buildings and constructions in the Settlement of Konstantinovka to the mobility of basement faults in the southern part of the Nizhnyaya Zeya Basin. Aseismic deformations are determined by slow horizontal tectonic movements in the junction zone of NNE-trending structures of the latter basin and near-latitudinal faults of the Khailar-Xunhei Belt. 相似文献
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San’kov V. A. Lukhnev A. V. Parfeevets A. V. Miroshnichenko A. I. Ashurkov S. V. 《Doklady Earth Sciences》2011,436(1):159-164
The complex analysis of parameters characterizing the modern deformations of the Earth’s crust and upper mantle in the territory
of the Mongolia-Siberian Area is made. Directions of principal tension axes of stress-tensors, calculated with the use of
earthquake source mechanisms have been taken as parameters of modern deformations at the level of the middle crust; directions
of axes of horizontal strains in the geodesic network by the GPS data have been taken as such parameters at the level of the
Earth’s surface. The strain parameters for the mantle depths are the data on seismic anisotropy derived from the published
sources about the results of studies on splitting of transversal waves from distant earthquakes. Seismic anisotropy is interpreted
as the ordered orientation of olivine crystals, which appears with great strains resulting from the flow of the mantle material.
It has been shown that directions of extensional strain axes (minimal compression) by geodesic and seismological data coincide
with anisotropy directions in the upper mantle in the region whose median value is 310°–320°. The observed mechanical coupling
of the crust and the upper mantle of the Mongolia-Siberian Mobile Area shows the participation of the lithospheric mantle
in the formation of neotectonical structures and enables us to distinguish the principal processes determining the Late Cenozoic
tectogenesis in this territory. One of the leading mechanisms for the neotectonical and modern deformations of the Mongolia-Siberian
Region is the large-scale NW-SE material flow in the upper mantle causing both motion of the entire northern part of the continent
and divergence of the Eurasia and the Amurian Plate. Lithospheric deformations in the western part of the region are related
to collision-induced compression, while those in the central part are caused by interaction of these large-scale tectonic
processes. 相似文献
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V. A. Sankov A. V. Lukhnev A. I. Miroshnitchenko A. A. Dobrynina S. V. Ashurkov L. M. Byzov M. G. Dembelov E. Calais J. Déverchère 《Izvestiya Physics of the Solid Earth》2014,50(6):785-794
The contemporary horizontal movements and deformations in the central and southern parts of the Baikal depression are analyzed, and their relationship with contemporary seismicity is studied. Based on the long-term measurements by the Baikal geodynamical GPS monitoring network, the refined estimate is obtained for the velocity of the divergence of the Siberian and Transbaikalian blocks, which is found to occur in the southeastward direction (130°) at 3.4 ± 0.7 mm per annum. This agrees with the parameters of the long-term extension component estimated from the geological data and with the direction of extension determined from the seismic data. The distribution of the displacement velocity across the strike of the rift, which gradually increases from one block to another, suggests a nonrigid behavior of the continental lithospheric plates at the divergent boundary. About 30% (1.0–1.5 mm per annum) of the total increase in the velocity is accommodated by the Baikal Basin. The strain rate within the trough reaches 3.1 × 10?8 yr?1 and decreases on either side across the structure. The character of distribution of the horizontal displacement velocities on the Baikal divergent boundary between the Eurasian and Amurian plates favors the model of passive rifting. The zones of highly contrasting topography and increased seismicity are localized within the area of contemporary deformations, and the seismic moment release rate directly depends on the strain rate. Here, the rate of the seismic moment release rate makes up a few percent of the geodetic moment accumulation rate calculated by the approach suggested by Anderson (1979). Based on the coherence between the graphs of the rates of geodetic moment accumulation and seismic moment release rate by the earthquakes with M ≥ 5.0 during the historical and instrumental observation periods, the contemporary seismic hazard for the South Baikal Basin could be assessed at a level of seismic event with M = 7.5–7.6. 相似文献
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Lukhnev A. V. Sankov V. A. Miroshnichenko A. I. Sankov A. V. Byzov L. M. 《Doklady Earth Sciences》2021,500(1):756-760
Doklady Earth Sciences - The measurement data obtained at the GPS network in the southwestern part of the Baikal Rift System for the period from 1994 to 2020 were analyzed. The spatial relationship... 相似文献
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A.V. Lukhnev V.A. San’kov A.I. Miroshnichenko S.V. Ashurkov L.M. Byzov A.V. San’kov Yu.B. Bashkuev M.G. Dembelov E. Calais 《Russian Geology and Geophysics》2013,54(11):1417-1426
Based on multiyear measurements of present-day motions in the central area of the Baikal rift system, new data on the kinematics of horizontal motions, relative horizontal deformation rates, and rotation velocities in the area of junction of the South Baikal, North Baikal, and Barguzin rift basins have been obtained. This area is an intricate structure with two transfer zones: Ol’khon–Svyatoi Nos and Ust’-Barguzin.It is shown that crustal blocks are moving southeastward, normally to the structures of transfer zones and at an acute angle to the Baikal Rift strike, which corresponds to the right-lateral strike-slip extensional faulting along the major structure. The average horizontal velocities increase from 3.0 mm yr–1 in the northern South Baikal basin to 6.5 mm yr–1 in the Barguzin basin. The elongation axes prevailing in the study region are mainly of NW–SE direction. The areas of intense deformations are confined to structures with high seismic activity in the South Baikal and, partly, Barguzin basins. This confirms the existence of a present-day zone of the Earth’s crust destruction in the Baikal rift system, which is the most likely source of strong earthquakes in the future. Two zones with rotations in opposite directions are recognized in the rotation velocity field. Clockwise rotation is typical of structures of N–NE strike (Maloe More basin, southern North Baikal basin, Barguzin Ridge rise). Counterclockwise rotation is determined for NE-striking structures (northern South Baikal basin, southern Barguzin basin). In general, the obtained data show an intricate pattern of present-day horizontal dislocations and deformations in the area of junction of NE- and N–NE-striking rift structures. This suggests left- and right-lateral strike-slip faults, respectively, within them. 相似文献
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A.I. Miroshnichenko N.A. Radziminovich A.V. Lukhnev F.L. Zuev S. Demberel D. Erdenezul M. Ulziibat 《Russian Geology and Geophysics》2018,59(8):1049-1059
First results of the analysis of GPS measurement data obtained from 18 sites of two local networks in the vicinity of Ulaanbaatar (Mongolia) for the period 2010–2015 have been presented. Horizontal velocity vectors are consistent with each other in the ITRF2014 system and with the velocities of the IGS permanent station ULAB. The sites move in the E–SE direction at a rate of 25–30 mm/yr, with the displacement azimuth averaging 105°. With respect to Eurasia, the vectors for most of the sites are slighly turned to the south, but they are still of SE orientation with the azimuth range of 130°–150° and magnitude values of 2–4 mm/yr. Relative horizontal velocities tend to decrease towards southeast that determines a zonal distribution of different type of relative strain patterns. The western part of the Ulaanbaatar network is characterized by the W–E oriented extension with the elongation rate ε1 = 12–16 × 10–8 yr–1. The shortening NW–SE trending strain with calculated value ε2 = 22.4 × 10–8 yr–1 characterizes the network’s eastern part. The highest values of the maximum shear strains (εmax = 10–14 × 10–8 yr–1) form an extended area in the center of the testing ground, which is elongated in the northeastern direction, conformably with the strike of the major geologic structures. The strain distribution pattern of the Emeelt network located within the eponymous seismogenic structures is characterized by the crustal elongation (5 × 10–6 yr–1) trending SE–NW and less pronounced shortening in the SW–SE directions.The axial part of the fault crossing the network in the NW direction exhibits maximum deformations. 相似文献
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A.V. Lukhnev V.A. San'kov A.I. Miroshnichenko S.V. Ashurkov E. Calais 《Russian Geology and Geophysics》2010,51(7):785-793
Current deformation in Pribaikalia, Western and Central Mongolia, and Tuva has been studied from measured horizontal GPS velocities and respective computed strain and rotation rates using 1994–2007 data of the Baikal–Mongolian GPS triangulation network.The GPS velocity field shows two main trends: an NE trend within Jonggaria, the Mongolian Altay, and the Great Lakes Valley and an SE trend in the Hangayn and eastern Gobi Altay mountains, and in the Transbaikalian block of the Amur plate. The velocity magnitudes and vectors are consistent with an SE motion of the Amur plate at a rate of ～2 mm/year.The derived strain pattern includes domains of crustal contraction and extension recognized from the magnitudes of relative strains. Shortening predominates in the Gobi and Mongolian Altay and in the Khamar-Daban Range, where it is at ?2 = (19.2 ± 6.0)×10?9 yr?1 being directed northeastward. Extension domains exist in the Baikal rift and in the Busiyngol–West Hangayn area, where the crust is stretching along NW axes at ?1 = (22.2 ± 3.1) × 10–9 yr–1. The eastern Hangayn dome and the Gobi peneplain on its eastern border show low and unstable strain rates. In central and northern Mongolia (Orhon–Selenge basin), shortening and extension are at similar rates: ?2 = (15.4 ± 5.4)×10?9 yr?1 and ?1 = (18.1 ± 3.1)×10?9 yr?1. The strain pattern changes notably in the area of the Mogod earthquake of 1967.Most of rotation throughout Central Asia is clockwise at a low rate of about Ω = 6×10?9 deg·yr?1. High rates of clockwise rotation are observed in the Hangayn domain (18.1 ± 5.2)×10?9 deg·yr?1, in the Gobi Altay (10.4 ± 7.5)×10?9 deg·yr?1, and in the Orhon–Selenge domain (11.9 ± 5.2)×10?9 deg·yr?1. Counterclockwise rotation is restricted to several domains. One is in western Tuva and northwestern Great Lakes Valley of Mongolia (Ω = 3.7×10?9 deg·yr?1). Two more counterclockwise rotation regions occur on both flanks of the Baikal rift: along the craton edge and in basins of Transbaikalia on the rift eastern border, where rotation rates are as high as (13.0 ± 3.9)×10?9 deg·yr?1, while rotation within the Baikal basin does not exceed the measurement error. Another such domain extends from the eastern Hövsgöl area to the Hangayn northern foothills, with the counterclockwise rotation at a highest rate of (16.3 ± 2.8)×10?9 deg·yr?1. 相似文献
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