Geodynamics & Tectonophysics最新文献_第8页

Helium in groundwaters of the Altai Republic 阿尔泰共和国地下水中的氦

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Geodynamics & Tectonophysics Pub Date : 2020-09-23 DOI: 10.5800/gt-2020-11-3-0497

E. Dutova, V. Kats, A. Shitov, A. Surnin, V. Molokov

{"title":"Helium in groundwaters of the Altai Republic","authors":"E. Dutova, V. Kats, A. Shitov, A. Surnin, V. Molokov","doi":"10.5800/gt-2020-11-3-0497","DOIUrl":"https://doi.org/10.5800/gt-2020-11-3-0497","url":null,"abstract":". This study of groundwaters of the Altai Republic is relevant due to the need to identify earthquake precursors in seismically active zones of the study area. Chemical composition of groundwater is widely known as an indicator of seismic processes, which changes in future earthquake focal zones. In this regard, studying helium contents in groundwater is of particular importance – anomalous concentrations of helium are typical of fault zones, and helium concentration variations in time can be referred to as earthquake precursors. Our study was focused on the distribution of helium in groundwaters of the Altai Republic and aimed to determine and justify positioning of permanent monitoring sites for investigation of earthquake precursors. During the field study, groundwater samples were taken from wells and springs located within the area covered by the established state monitoring network (GONS). Groundwater aquifers and water-bearing zones from Quaternary to Proterozoic ages were sampled. Analysis of the groundwater samples shows spatial variations of helium concentration in the study area. Water samples from fault zones have increased concentrations of helium. The concentration of helium is high in the groundwater from the Chuya artesian basin, i.e. near the epicentral zone of the M 7.5 Altai (Chuya) earthquake of September 27, 2003.","PeriodicalId":44925,"journal":{"name":"Geodynamics & Tectonophysics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2020-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74261702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Collision system of West Pribaikalie: aerospace geological map of Olkhon Region (Baikal, Russia) 西普里贝加尔湖碰撞系统:俄罗斯贝加尔湖奥尔洪地区航空航天地质图

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Geodynamics & Tectonophysics Pub Date : 2020-09-23 DOI: 10.5800/gt-2020-11-3-0485

V. S. Fedorovsky, E. Sklyarov, D. Gladkochub, A. Mazukabzov, T. Donskaya, A. V. Lavrenchuk, A. Starikova, N. Dobretsov, A. Kotov, A. V. Tevelev

引用次数: 4

Models of the macroseismic field earthquakes and their influence on seismic hazard assessment values for Central Asia 中亚地区大地震场地震模型及其对地震危险性评价值的影响

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Geodynamics & Tectonophysics Pub Date : 2020-09-23 DOI: 10.5800/gt-2020-11-3-0494

T. Artikov, R. Ibragimov, T. L. Ibragimova, M. Mirzaev

{"title":"Models of the macroseismic field earthquakes and their influence on seismic hazard assessment values for Central Asia","authors":"T. Artikov, R. Ibragimov, T. L. Ibragimova, M. Mirzaev","doi":"10.5800/gt-2020-11-3-0494","DOIUrl":"https://doi.org/10.5800/gt-2020-11-3-0494","url":null,"abstract":"Seismic intensity assessment in points of a macroseismic scale plays an important role for researching the seismic history of areas characterized by active seismicity, as well as for construction (and updating) of seismic zoning maps in various scales. Macroseismic scale points are generally referred to in construction standards applied in the majority of post-Soviet states. In our study aimed to model the macroseismic field of earthquakes, a large volume of macroseismic data on Central Asia was analyzed, and coefficients used in Blake–Shebalin and Covesligeti equations were aligned. This article presents a generalized dependence model of macroseismic intensity attenuation with distance. The model takes into account seismic load features determined by various depths of earthquakes. The ratios of small and big axes of the ellipse, that approximates real isoseists, are estimated with respect to seismic scale points, earthquake depths and magnitudes. The East Uzbekistan area is studied as an example to investigate whether seismic hazard assessment values may differ depending on a chosen law of seismic influence intensity attenuation with distance.","PeriodicalId":44925,"journal":{"name":"Geodynamics & Tectonophysics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2020-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80001125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Inhomogeneous structure of magnetic layer of the Kuril Island Arc 千岛岛弧磁层的非均匀结构

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Geodynamics & Tectonophysics Pub Date : 2020-09-23 DOI: 10.5800/gt-2020-11-3-0492

N. Palshin, A. Ivanenko, D. Alekseev

引用次数: 2

Tectonics of rock loosening: geological data and physics of the process 岩石松动的构造:地质资料和过程的物理

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Geodynamics & Tectonophysics Pub Date : 2020-09-23 DOI: 10.5800/gt-2020-11-3-0488

M. G. Leonov, G. Kocharyan, A. Revuzhenko, S. Lavrikov

引用次数: 3

Late Mesozoic adakite granites of the southern frame of the eastern flank of the Mongol-Okhotsk orogenic belt: material composition and geodynamic conditions of formation 蒙古-鄂霍次克造山带东翼南架晚中生代埃达克岩花岗岩:物质组成及形成地球动力学条件

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Geodynamics & Tectonophysics Pub Date : 2020-09-23 DOI: 10.5800/gt-2020-11-3-0487

I. Derbeko, A. Chugaev

{"title":"Late Mesozoic adakite granites of the southern frame of the eastern flank of the Mongol-Okhotsk orogenic belt: material composition and geodynamic conditions of formation","authors":"I. Derbeko, A. Chugaev","doi":"10.5800/gt-2020-11-3-0487","DOIUrl":"https://doi.org/10.5800/gt-2020-11-3-0487","url":null,"abstract":". Granitoids of the Magdagachi complex were studied using new and published petrochemical, geochemical and isotopic (Sm-Nd, Rb-Sr) data. Granitoid samples were taken from the southern frame of the eastern flank of the Mongol-Okhotsk orogenic belt (MOOB). Their analysis shows increased concentrations of Sr, Ba, Eu; reduced concentrations of Nb, Ta; abnormally low concentrations of HREE, Y and Yb; significant fractionation of REE; and high Sr/Y ratios. Therefore, the Magdagachi granitoids are \"classical\" adakites that may have formed at a depth of more than 45 km due to melting of eclogite with a garnet content of 20–50 %. Such conditions could exist under subduction as a result of melting of the frontal or lateral parts of the slab in subduction windows formed during oblique subduction at an orthogonal sinking angle. Highly metamorphosed lower crust Precambrian formations were also melted, and a source of parental melts could have been composed of both the mantle and crustal materials. Two tectonic scenarios are proposed that could have been accompanied by the formation of Magdagachi granitoids. Both scenarios refer to subduction processes, but differ in interactions between various regional structures in the Late Mesozoic.","PeriodicalId":44925,"journal":{"name":"Geodynamics & Tectonophysics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2020-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76988412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Archive data on climate changes and seismic events in glacial clays of Lake Kucherla (Altai region, Russia) 俄罗斯阿尔泰地区库切拉湖冰川粘土气候变化与地震事件档案资料

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Geodynamics & Tectonophysics Pub Date : 2020-09-23 DOI: 10.5800/gt-2020-11-3-0495

A. Darin, G. Chu, Q. Sun, V. Babich, I. Kalugin, T. Markovich, V. S. Novikov, F. Darin, Y. Rakshun

引用次数: 1

Geological-geophysical models of the crust for the White Sea region 白海地区地壳的地质-地球物理模型

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Geodynamics & Tectonophysics Pub Date : 2020-09-23 DOI: 10.5800/gt-2020-11-3-0491

N. Sharov, L. Bakunovich, B. Belashev, V. Zhuravlev, M. Nilov

引用次数: 3

Late Quarternary displacements along the Sarma segment of the Primorsky fault based on gpr survey data (Baikal rift) 基于gpr测量资料的滨海断裂带萨尔马段晚第四纪位移(贝加尔湖裂谷)

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Geodynamics & Tectonophysics Pub Date : 2020-09-23 DOI: 10.5800/gt-2020-11-3-0490

I. Denisenko, O. Lunina

{"title":"Late Quarternary displacements along the Sarma segment of the Primorsky fault based on gpr survey data (Baikal rift)","authors":"I. Denisenko, O. Lunina","doi":"10.5800/gt-2020-11-3-0490","DOIUrl":"https://doi.org/10.5800/gt-2020-11-3-0490","url":null,"abstract":". Ground-penetrating radar (GPR) surveys were performed in the Sarma segment of the Primorsky fault between the settlements of Shida and Kurma. This segment belongs to one of the largest structures of the Baikal rift and was active in Late Quaternary (Early Holocene). The study aimed to reconstruct vertical displacement amplitudes and dip angles of fractures along the fault segment, clarify its kinematic type, and estimate a maximum magnitude of earthquakes that may occur in the study area. The GPR equipment set included an OKO-2 georadar and AB-250M and ABDL-Triton shielded antennas. The GPR surveys were supported by morphostructural and tectonophysical methods. Based on the interpretation of the geophysical survey data and satellite images, faults associated with the Sarma paleoseismic dislocation were mapped. Their total length amounts to 14 km. According to the GPR survey data, one-stage vertical displacements show normal faulting and vary from SW to NE from 4.4 to 7.7 m. Paleo-earthquake magnitudes calculated from the maximum displacement values (Mw=7.2, and Мs=7.4) suggest that potential earthquakes in the Primorsky fault zone may be stronger than previously assumed.","PeriodicalId":44925,"journal":{"name":"Geodynamics & Tectonophysics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2020-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83297060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Hydrogeochemical zoning of uranium isotopes (234U/ 238U) in the Southern Siberian paleocontinent: the role of the South Baikal reservoir in the groundwater formation 南西伯利亚古大陆铀同位素(234U/ 238U)的水文地球化学分带:南贝加尔湖水库在地下水形成中的作用

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Geodynamics & Tectonophysics Pub Date : 2020-09-23 DOI: 10.5800/gt-2020-11-3-0496

S. Rasskazov, A. Ilyasova, I. Chuvashova, S. Bornyakov, A. I. Orgilyianov, S. N. Kovalenko, A. Seminsky, E. P. Popov, E. Chebykin

{"title":"Hydrogeochemical zoning of uranium isotopes (234U/ 238U) in the Southern Siberian paleocontinent: the role of the South Baikal reservoir in the groundwater formation","authors":"S. Rasskazov, A. Ilyasova, I. Chuvashova, S. Bornyakov, A. I. Orgilyianov, S. N. Kovalenko, A. Seminsky, E. P. Popov, E. Chebykin","doi":"10.5800/gt-2020-11-3-0496","DOIUrl":"https://doi.org/10.5800/gt-2020-11-3-0496","url":null,"abstract":"The southern deformed edge of the Siberian paleocontinent is studied for zoning the disturbance of 234U/238U cyclic equilibrium in groundwaters discharged to the accreted Khamardaban terrane. A relationship is established between vertical variations of 234U/238U (ОА4/8) activity ratios and the hydrogeochemical zoning of groundwaters. Lateral ОА4/8 zoning of groundwaters in the basement rocks and sedimentary cover of the Siberian platform is described. It is emphasized that an important role is played by the water propagating from the South Baikal reservoir (SBR) (ОА4/8 = 1.95–1.99; U content = 0.44–0.46 μg/L) under the shore of Lake Baikal. It is suggested that the lateral advancement of the SBR water is facilitated by the development of low-angle (weakened by rifting) fractures of the Angara thrust fault, as well as subvertical fractures in the shear zone of the Main Sayan Fault. Monitoring data on the study area show that the ratios of the groundwaters components vary in time due to Cherdyntsev – Chalov deformational effect, chemical interaction of the waters and evaporites, and mixing of the groundwaters with contrasting hydrogeochemical signatures.","PeriodicalId":44925,"journal":{"name":"Geodynamics & Tectonophysics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2020-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86531396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2