Stressandstrain reconstruction for the eastern segment of the Baltic shield

Sim, L. A.; Жиров, Дмитрий Вадимович; Marinin, A. V.

doi:10.5800/gt-2011-2-3-0044

Cited by 17 publications

(9 citation statements)

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“…2) is timed to the fault limiting Arkhangelsk scarp and the Onega-Kandalaksha ancient rift. The focal mechanism of this earthquake calculated in study (Morozov et al 2016) is fully in line with the conclusions of L.A. Sim (Sim et al 2011) on regional submeridional compression and sublatitudinal tension characteristic of the eastern part of the Baltic shield.…”

Section: Discussionsupporting

confidence: 86%

Updated data on the current seismicity of the White Sea and the Karelian region during the period 2005–2016

Konechnaya¹,

Morozov²,

Vaganova³

et al. 2019

AER

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This article is the result of previous studies to clarify the seismicity of the White sea, supplemented by similar studies on the continental part of the Republic of Karelia. The relocated catalog of earthquakes was created for the period from 2005 to 2016 for White Sea and the Karelian region. With the help of proven methods, the parameters of the epicenters of identified earthquakes were relocated and a map of current seismicity was obtained. The parameters of the epicenters were specified using BARENTS travel-time model, a single methodological approach (using Generalized beamforming) and all currently available source data and bulletins of Russian and foreign seismic stations. The obtained seismic catalog allowed us to identify the main patterns of the distribution of current seismicity in the White Sea region. Seismicity of the White sea and the Karelian region is characterized as low-magnitude (generally of low magnitude with ML<2.0). Most earthquakes in the White Sea are characterized by a focal depths up to 20 km. Analysis of catalog shows that the majority of earthquakes are concentrated in the north-western part of the defined area, in the continental part of Karelia and Kandalaksha graben. Some earthquakes were recorded in the eastern and central part of the White sea.

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Section: Discussionsupporting

confidence: 86%

Updated data on the current seismicity of the White Sea and the Karelian region during the period 2005–2016

Konechnaya¹,

Morozov²,

Vaganova³

et al. 2019

AER

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“…На Балтийском щите (рис. 4) кинематическим методом восстановлены тектонические напряжения I ранга на территории Карелии и серия общих полей II ранга, которые дали основание отнести Балтийский щит к западному типу напряженного состояния по аналогии с ЗЕП и западной частью Русской плиты [Sim et al, 2011]. В окрестностях Кандалакшского залива восстановлен геодинамический режим горизонтального растяжения, ориентированного поперек Кандалакшского реактивизированного грабена, что соответствует новейшей структуре.…”

Section: восточно-европейская платформаunclassified

Results of the tectonic stress study of the Northern Eurasia regions

Sim

Marinin

Брянцева

et al. 2018

Geodin. tektonofiz.

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The article presents the results obtained by field tectonophysical methods applied to study tectonic stresses of the Northern Eurasia regions, including young and ancient platforms (West European, Timan–Pechora, Turan, West Siberian, East European, and East Siberian) and orogenic frame structures (Caucasus, Northern Tien Shan, Mongolia-Okhotsk system of mesozoids, and Sakhalin Island). Tectonic stress reconstructions provided the basis for analysing the influence of spreading in the North Atlantics and the Arctic on the stress state of the platforms in Northern Europe. A spatial boundary of the influence goes approximately along the margins of the Fennoscandian shield and the Russian plate in the north. Further southwards, the boundary is submeridional and extends from the western wing of the Byelorussian anteclise almost to the Eastern Carpathians. The stress reconstructions for this boundary show the WNW and W-E-trending axes of compression. The boundary line does not coincide with the Teisser-Tornquist line that represents the boundary between the platforms with heterochronous basements. However, it correlates well with heat flow anomalies. The boundary area is confined to the Baltic coast [Sim, 2000. Along the boundary area, near the Baltic Sea, there is an area wherein faulting is mainly caused by extension [Sim, 2000. In this setting, helium permeability is the highest, as shown by the crust map of the European part of the USSR [Eremeev,1983. Extension in this area is probably related to formation of young grabens in the Baltic shield. Changes in the compression axis orientation may be due to the alternating activations of the grabens in the submeridionalBotnicGulf and the latitudinalGulf of Finland. Reconstructions for individual faults show contradictions in the directions of shear displacements: both right- and left-lateral displacements are possible on the same fault segments, and the axes of compression can have either latitudinal or meridional orientations. The focal mechanisms of the Osmussaar andKaliningrad earthquakes (meridional and latitudinal axes of compression, respectively) give evidence of specific current neotectonic stresses in this area. Another zone is distinguished at 52°N from the above-described area. It is mainly sublatitudinal and detected along the southern flank of the Byelorussian anteclise. Further to the east, its orientation changes to SSW, and it roughly follows the SW boundary of theVoronezh anteclise. Reconstructions for the Ukrainian Shield, located south of this zone, show mainly the unstable orientations of the axes of compression. For the platforms inNorthern Eurasia, the tectonophysical methods reconstructed neotectonic stresses in the structures formed under the influence of intraplatform tectonic stresses. These are the residual gravitational horizontal compression stresses released by long-term denudation and uplifting of the structures, including the Khibiny massif of the Baltic Shield, theOlenek and Munsky massifs of the East Siberian platform. These structures are composed of the ancient Archaean-Proterozoic rock complexes, which have been subjected to predominantly vertical displacements for a long time, from the Paleozoic to the modern stage. Special attention should be given to the tectonic stresses ofSakhalin located at the boundary between the Eurasian and North American lithospheric plates. At the edges of these two largest plates, there are the Amur and Okhotsk microplates separated by theCentral Sakhalin fault, as described in some publications. Neotectonic stress reconstructions forSakhalinIsland show sublatitudinal compression and submeridional extension in the common stress field of shearing. The tectonophysical studies show that the neotectonic stresses differ in large structures: horizontal compression and shearing are typical of the uplifts (Kola Peninsula, Tien Shan, Sakhalin), while horizontal extension and extension with shearing are characteristic of depressions (Kandalaksha graben, depressions of theTatarGulf and theSea ofOkhotsk). Our studies provide the data on spacious ‘white spots’ in the modern stress maps ofNorthern Eurasia. The stress reconstructions for practically all the studied structures show that shearing is the dominant geodynamic regime in the study region.

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“…29 измерено 19 векторов перемещения, по кото-рым восстановлено одно ЛСС (объем 22, таблица); ориентировка растяжения  1 соответствует моло-дому ЛСС (объем 21а), но в объеме 22 ось сжатия  3 поменялась местами с промежуточной осью  2 . Та-кая переиндексация осей главных нормальных напряжений в разных крыльях разломов отмечена по данным моделирования сдвигов [Osokina, 1987] и при изучении разломов в реальной геологиче-ской среде [Sim et al, 2011]. Хорошая сохранность борозд скольжения в лежачем крыле разлома дает возможность отнести возраст ЛСС в объеме 22 к более молодому.…”

Section: Orientations Of Tectonic Stresses In the Southern Sakhalinunclassified

“…Ориентировки оперяющих разрывов в зонах сдвигов легли в обоснование СГ метода, давшего возможность оха-рактеризовать новейшее напряженное состояние Северного и Центрального Сахалина. Опыт преды-дущих полевых тектонофизических исследований на Балтийском щите, Северном Тянь-Шане показал, что ЛСС в разных крыльях разломов резко меняют-ся [Sim, 2000;Sim et al, 2011Sim et al, , 2014. Эти полевые ис-следования ЛСС в разных крыльях разломов цели-ком соответствуют данным моделирования текто-нических напряжений в окрестностях разрывов [Osokina, 1987].…”

Section: обсуждение результатовunclassified

Neotectonics and tectonic stresses of the Sakhalin Island

Sim

Богомолов²,

Брянцева³

et al. 2017

Geodin. tektonofiz.

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Abstract:The paper describes the neotectonics of the Sakhalin Island and analyzes the latest and recent tectonic stresses in the study area in order to establish their differences in the Amur and Okhotsk microplates, which boundary is confined to the Tym-Poronaisk fault, the largest NS-striking fault in the Central Sakhalin (Fig. 1). Our map of the structural geomorphological features of the study area (Fig. 2) shows three longitudinal zones: the western and eastern uplifts, and the Central Sakhalin basin between the uplifts. In the Southern Sakhalin, neotectonic stresses were studied by a combination of tectonophysical methods and the method of structural geology (Figures 3 to 6, and Table). Our study shows that the regional axes of maximum and minimum compressive principal normal stresses are primarily of the subhorizontal orientations (Fig. 5, Д). In the Northern and Central Sakhalin, neotectonic stresses were reconstructed by the structural geomorphology method. The compression axes are oriented sublatitudinally, with the NE-trending strike in the Northern Sakhalin (Fig. 7, A), and the extension axes are oriented submeridionally; in the Northern Sakhalin, respectively, they are oriented in the NW direction. The results of our study of neotectonic stresses were used to construct a map of recent geodynamics of Sakhalin (Fig. 7, Б), which shows zones differing in the geodynamic settings of the most recent faulting. According to the analysis of the recent tectonic stress with respect to the earthquake focal mechanisms in the period from 1978 to 2015 (Fig. 8), recent stresses dominating in Sakhalin have mainly the sublatitudinal low-angle orientations of the deviatoric compression axis. The submeridional low-angle orientations of the deviatoric extension axes are observed in the Northern Sakhalin and partly in the north of the Southern Sakhalin (see Fig. 8). The high-angle axes of deviatoric extension are typical of the western and central parts of the Southern Sakhalin, and such extension leads to horizontal compression and reverse faulting. In some areas of the recent stress field, the deviatoric axes of compression and extension have unstable orientations. The latitudinal boundaries of such areas are nearly coincident with the boundaries of the zones that differ in the geodynamic settings of the most recent faulting, which means that these areas and zones are reliably identified. The relative inhomogeneity of the neotectonic and recent stress fields in the Southern Sakhalin does not give grounds to distinguish differences in the state of crustal stresses in the areas located on the sides of the Southern Sakhalin fault. As a consequence, a boundary between the Amur and the Okhotsk Plate in the South Sakhalin cannot be drawn along this fault. It is most likely that this boundary coincides with the Western-Sakhalin fault in the southern areas of the study region. Our data on the Central and Northern Sakhalin does not contradict with the conclusion in [Savostin et al., 1982] concerning this boundary.

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Stressandstrain reconstruction for the eastern segment of the Baltic shield

Cited by 17 publications

References 1 publication

Updated data on the current seismicity of the White Sea and the Karelian region during the period 2005–2016

Updated data on the current seismicity of the White Sea and the Karelian region during the period 2005–2016

Results of the tectonic stress study of the Northern Eurasia regions

Neotectonics and tectonic stresses of the Sakhalin Island

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