scholarly journals THE CURRENT STRESS OF EARTH'S CRUST IN THE TERRITORY OF UZBEKISTAN ACCORDING TO FOCAL EARTHQUAKE MECHANISMS

2021 ◽  
Vol 12 (3) ◽  
pp. 435-454
Author(s):  
T. L. Ibragimova ◽  
R. S. Ibragimov ◽  
M. A. Mirzaev ◽  
Yu. L. Rebetsky
Keyword(s):  
Active Regions ◽  
Earth’S Crust ◽  
Stress Fields ◽  
Shear Stresses ◽  
Internet Resource ◽  
Homogeneous Sample ◽  
Current Stress ◽  
Minimum Number ◽  
Different Depths ◽  
Earth's Crust

The current stress of Earth's crust in the territory of Uzbekistan has been studied using a focal earthquake mechanisms catalogue that includes the data provided by many authors. Stress reconstructions are based on the cataclastic analysis of displacements along fractures. For reconstructing the stress state at different depths of the crust in several seismically active regions of the study area, we consider a minimum number of earthquakes in a homogeneous sample equal to 6 and an averaging radius of 10 to 30 km within a single domain. The azimuths and dip angles of the principal stress axes, Lode – Nadai coefficients, geodynamic types of stress modes, relative (normalized to rock strength) values of maximum shear stresses, and effective pressure values are determined. Maps showing the spatial distribution of the studied parameters are constructed for both the entire seismically active layer and the depth layers. Stress fields are reconstructed and compared at two hierarchical levels based on the parameters of focal mechanisms of weak and moderate earthquakes (М≤4.5) and those of strong (М≥5.0) earthquakes. "Tectonic Stresses of Eurasia", the Internet resource created by IPE RAS, is used to visualize the stress field reconstructed from the data on strong (М≥5.0) earthquakes.

scholarly journals System for Collecting, Processing, Visualization, and Storage of the MT-Monitoring Data

Data ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 99 ◽  
Author(s):  
Elena Bataleva ◽  
Anatoly Rybin ◽  
Vitalii Matiukov
Keyword(s):  
Practical Importance ◽  
Active Regions ◽  
Tien Shan ◽  
Earth’S Crust ◽  
Management Tool ◽  
Research Station ◽  
Depth Range ◽  
Integrated Monitoring ◽  
Geodynamic Processes ◽  
Earth's Crust

On the basis of the Research Station of the Russian Academy of Sciences in Bishkek, a unique scientific infrastructure—a complex geophysical station—is successfully functioning, realizing a monitoring of geodynamic processes, which includes research on the network of points of seismological, geodesic, and electromagnetic observations on the territory of the Bishkek Geodynamic Proving Ground located in the seismically active zone of the Northern Tien Shan. The scientific and practical importance of monitoring the geodynamical activity of the Earth’s crust takes place not only in seismically active regions, but also in the areas of the location of particularly important objects, mining, and hazardous industries. Therefore, it seems highly relevant to create new software and hardware to study geodynamic processes in the earth’s crust of seismically active zones, based on integrated monitoring of the geological environment in the widest possible depth range. The use of modern information technology in such studies provides an effective data management tool. The considering system for collecting, processing, and storing monitoring electromagnetic data of the Bishkek geodynamic proving ground can help overcome the scarcity of experimental data in the field of Earth sciences.

Energy-4 Generator for Monitoring Seismically Active Regions and Electromagnetic Sounding of the Earth’s Crust. Experience of Application in the Kovdor-2015 Experiment

2018 ◽  
Vol 54 (3) ◽  
pp. 268-280 ◽  
Author(s):  
V. V. Kolobov ◽  
M. B. Barannik ◽  
B. V. Efimov ◽  
A. A. Zhamaletdinov ◽  
A. N. Shevtsov ◽  
...  
Keyword(s):  
Active Regions ◽  
Earth’S Crust ◽  
Electromagnetic Sounding ◽  
Earth's Crust

scholarly journals PRESENT-DAY STRESS FIELD AND RELATIVE DISPLACEMENT TENDENCY OF THE EARTH'S CRUST IN THE PARACEL ISLANDS AND ADJACENT AREA

2019 ◽  
Vol 18 (4) ◽  
pp. 460-474
Author(s):  
Tran Tuan Dung ◽  
R. G. Kulinich ◽  
Ngo Thi Bich Tram ◽  
Nguyen Quang Minh ◽  
Nguyen Ba Dai ◽  
...  
Keyword(s):  
Relative Displacement ◽  
Geometric Parameters ◽  
Earth’S Crust ◽  
Stress Fields ◽  
Adjacent Area ◽  
Time Period ◽  
Paracel Islands ◽  
Color Spectrum ◽  
Earth's Crust

Present-day stress filed in the Hoang Sa archipelago and adjacent areas is determined through the earthquake’s focal mechanism parameters that have been recorded during a time period of more than 100 years. The geometric parameters of the faults (such as the location, strike and dip angles as well as depth, length…) are determined by satellite-derived gravity, seismic data and stress fields. In this study, predictive determination of the magnitude and tendency of the relative displacement of the Earth’s crust is carried out by calculating and assessing the relationship between the stress fields and fault’s geometric parameters. On the basis of the Earth’s crust relative displacement, the geodynamic mechanism of the Hoang Sa archipelago and adjacent areas through the different geological periods can be rebuilt. Magnitude and tendency of the relative displacement of the Earth’s crust are represented by the color spectrum and the vector’s magnitude. Although the displacement appears in the whole region, its intensities are different in particular areas that have the faults systems with different grades.

scholarly journals Determination of energy parameters of seismic events of the Transcarpathian trough taking into account the quality factor of the Earth’s crust

2021 ◽  
Vol 43 (2) ◽  
pp. 218-226
Author(s):  
Yu.A. Andrushchenko ◽  
V.I. Osadchy ◽  
O.I. Lyashchuk ◽  
I.V. Kornienko ◽  
M.I. Halabuda
Keyword(s):  
Quality Factor ◽  
Active Regions ◽  
Seismic Wave Propagation ◽  
Earth’S Crust ◽  
Calibration Function ◽  
Energy Parameters ◽  
Local Earthquakes ◽  
Earth's Crust ◽  
Quantitative Indicators

Transcarpathia is characterized by significant differences in the structure and geodynamics of the lithosphere in comparison with other seismically active regions of Ukraine, which causes a number of features of the seismotectonic process of this region. The spatial distribution of the seismicity of the Transcarpathian Depression is closely related to the fault-block structure of the foundation. Important characteristics of the seismic process in Transcarpathia are the energy parameters of local earthquakes — magnitude, intensity, energy class. It is these values that form the basis of seismic zoning. The methods used to determine the energy parameters of local earthquakes do not fully take into account the effects of hypocenter depths and regional features of seismic wave propagation paths. Thus, the issue of determining the quantitative indicators of the quality factor of the Earth’s crust of the studied region and the development of approaches to determining the calibration function for estimating local magnitudes is relevant. The article presents the results of the study, which are aimed at determining the calibration function for calculating the energy characteristics of earthquakes in the Transcarpathian Depression, taking into account the parameters of attenuation of the Earth’s crust. Using digital records of seismic signals from the Transcarpathian Depression, obtained on the elements of the Ukrainian seismic group, as well as seismic stations «Stone Bridge», «Pidluby», «Zelenytsia» and «Lyubar» were determined quantitative indicators of the quality of the Earth’s crust and developed approaches to determination of the calibration function for estimation of local magnitude and its check on real signals.

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