scholarly journals STUDY OF THE DEPTH STRUCTURE OF SEISMICALLY ACTIVE ZONES BY THE METHOD OF MAGNETOTELLURIC SOUNDING

2021 ◽  
Vol 2 (1) ◽  
pp. 345-353
Author(s):  
Elena A. Bataleva
Keyword(s):  
Deep Structure ◽  
Test Site ◽  
Tien Shan ◽  
Magnetotelluric Soundings ◽  
Mountain Ranges ◽  
Transition Zones ◽  
Conductivity Anomalies ◽  
Active Zones ◽  
Intermontane Basins ◽  
Northern Tien Shan

The paper presents the results of the analysis of data from magnetotelluric soundings performed in 2003-2020. A comparison of geoelectric models for the Chui and Kochkor basins of the Northern Tien Shan is shown. The main objective of the study is to identify patterns in the distribution of geoelectric inhomogeneities in the deep structure of the Bishkek geodynamic test site. Particular attention in geoelectric models was paid to the study of key objects of transition zones from mountain ranges to intermontane basins. The nature of crustal electrical conductivity anomalies is considered.

scholarly journals STUDY OF THE DEPTH STRUCTURE OF SEISMICALLY ACTIVE ZONES BY THE METHOD OF MAGNETOTELLURIC SOUNDING

2021 ◽  
Vol 1 ◽  
pp. 137-143
Author(s):  
Elena A. Bataleva
Keyword(s):  
Deep Structure ◽  
Test Site ◽  
Tien Shan ◽  
Magnetotelluric Soundings ◽  
Mountain Ranges ◽  
Transition Zones ◽  
Conductivity Anomalies ◽  
Active Zones ◽  
Intermontane Basins ◽  
Northern Tien Shan

The paper presents the results of the analysis of data from magnetotelluric soundings performed in 2003-2020. A comparison of geoelectric models for the Chui and Kochkor basins of the Northern Tien Shan is shown. The main objective of the study is to identify patterns in the distribution of geoelectric inhomogeneities in the deep structure of the Bishkek geodynamic test site. Particular attention in geoelectric models was paid to the study of key objects of transition zones from mountain ranges to intermontane basins. The nature of crustal electrical conductivity anomalies is considered.

scholarly journals Mapping and inventorying active rock glaciers in the northern Tien Shan of China using satellite SAR interferometry

2017 ◽  
Vol 11 (2) ◽  
pp. 997-1014 ◽  
Author(s):  
Xiaowen Wang ◽  
Lin Liu ◽  
Lin Zhao ◽  
Tonghua Wu ◽  
Zhongqin Li ◽  
...  
Keyword(s):  
Quantitative Information ◽  
Google Earth ◽  
Tien Shan ◽  
Sar Interferometry ◽  
Western China ◽  
Mountain Ranges ◽  
Optical Images ◽  
Rock Glaciers ◽  
Altitudinal Limit ◽  
Northern Tien Shan

Abstract. Rock glaciers are widespread in the Tien Shan. However, rock glaciers in the Chinese part of the Tien Shan have not been systematically investigated for more than 2 decades. In this study, we propose a new method that combines SAR interferometry and optical images from Google Earth to map active rock glaciers (ARGs) in the northern Tien Shan (NTS) of China. We compiled an inventory that includes 261 ARGs and quantitative information about their locations, geomorphic parameters, and downslope velocities. Our inventory shows that most of the ARGs are moraine-derived (69 %) and facing northeast (56 %). The altitude distribution of ARGs in the western NTS is significantly different from those located in the eastern part. The downslope velocities of the ARGs vary significantly in space, with a maximum of about 114 cm yr−1 and a mean of about 37 cm yr−1. Using the ARG locations as a proxy for the extent of alpine permafrost, our inventory suggests that the lowest altitudinal limit for the presence of permafrost in the NTS is about 2500–2800 m, a range determined by the lowest ARG in the entire inventory and by a statistics-based estimation. The successful application of the proposed method would facilitate effective and robust efforts to map rock glaciers over mountain ranges globally. This study provides an important dataset to improve mapping and modeling permafrost occurrence in vast western China.

scholarly journals Mapping and inventorying active rock glaciers in the Northern Tien Shan (China) using satellite SAR interferometry

2016 ◽  
Author(s):  
Xiaowen Wang ◽  
Lin Liu ◽  
Lin Zhao ◽  
Tonghua Wu ◽  
Zhongqin Li ◽  
...  
Keyword(s):  
Quantitative Information ◽  
Google Earth ◽  
Tien Shan ◽  
Sar Interferometry ◽  
Western China ◽  
Mountain Ranges ◽  
North East ◽  
Optical Images ◽  
Rock Glaciers ◽  
Northern Tien Shan

Abstract. Rock glaciers are widespread in the high mountains of western China. However, they have not been systematically investigated for more than two decades. In this study, we propose a new method that combines SAR interferometry and optical images from Google Earth to map active rock glaciers (ARGs) in the Northern Tien Shan (NTS) in China. We compiled an inventory that includes 261 ARGs and quantitative information about their locations, geomorphic parameters, and down-slope velocities. Our inventory shows that most of the ARGs are moraine-derived (68 %) and facing north-east (56 %). The altitude distribution of ARGs in the western NTS is significantly different from those located in the eastern part. The down-slope velocities of the ARGs vary significantly in space, with a maximum of about 114 cm yr−1 and a mean of about 37 cm yr−1. Using the ARG locations as a proxy for the extent of alpine permafrost, our inventory suggests that the lowest altitudinal limit for the presence of permafrost in the Northern Tien Shan is about 2500–2800 m, a range determined by the lowest ARG in the entire inventory and by a statistics-based estimation. The successful application of the proposed method would facilitate an effective and robust effort to map rock glaciers over major mountain ranges and provide important datasets to improve mapping and modeling permafrost distribution in vast western China.

scholarly journals The relations between seismically active and electrically conductive zones

1997 ◽  
Vol 40 (2) ◽  
Author(s):  
I. G. Kissin ◽  
A. I. Ruzajkin
Keyword(s):  
Electrical Conductivity ◽  
Probable Mechanism ◽  
Tien Shan ◽  
Strained State ◽  
Sharp Drop ◽  
Electrically Conductive ◽  
Earthquake Sources ◽  
Active Zones ◽  
Northern Tien Shan ◽  
Vast Area

The higher electrical conductivity of rocks in the middle and lower parts of the Earth's crust is generally related to the presence of fluids in rocks. The metamorphic processes of dehydration contribute to release of fluids, above all, water; these processes are also responsible for an increase in rock porosity and fracturing. These processes influence the stressed-strained state of the medium under specific conditions. A probable mechanism of earthquake source formation on the contact of blocks with different rates of dehydration and, consequently, different electrical conductivity is discussed. The spatial positions of electrically conductive and seismically active zones are correlated and definite relations between them are found with special reference to the vast area of the Northern Tien Shan within Kirgizstan and some other regions. The greatest concentration of earthquake sources is observed mainly near the contacts between blocks with contrastingly different electrical conductivity values and on sites with a sharp drop in conductive-layer depths.

scholarly journals On the dynamics of the electromagnetic parameters of the Northern Tien Shan lithosphere

2021 ◽  
Vol 254 ◽  
pp. 03004
Author(s):  
Elena Bataleva
Keyword(s):  
Electromagnetic Field ◽  
Deep Structure ◽  
Wide Frequency Range ◽  
Tien Shan ◽  
Seismic Events ◽  
Kyrgyz Republic ◽  
Electromagnetic Parameters ◽  
Regional Seismicity ◽  
Time Frequency ◽  
Northern Tien Shan

The results of geophysical monitoring of seismically hazardous regions are of undoubted interest for studying the deep structure of the lithosphere, regional seismicity, modern geodynamics, etc. The work used experimental material, including the results of magnetotelluric monitoring and the catalogs of the KNET (Kyrgyzstan Telemetered Network), KRNET (Kyrgyz Republic Digital Network) and ISC (International Seismological Center) networks obtained in the seismically active zones of the Bishkek Geodynamic Proving Ground (Northern Tien Shan). The analysis of electromagnetic monitoring results of the Northern Tien Shan seismic generating zone was carried out in a wide frequency range. The data on the parameters of the electromagnetic field of the Earth’s crust in the Northern Tien Shan are generalized and systematized. Based on the analysis of these data, the dependence of the response of seismic events in electromagnetic parameters on the distance of earthquake epicenters was studied. The most likely reason for the occurrence of anomalous changes in the electromagnetic field is the activation of deformation processes during the preparation of strong earthquakes. The results of the time-frequency analysis are presented and the features of manifestation are considered depending on the location of the hypoand epicenters of seismic events and their magnitude. Regularities have been established in the behavior of tipper variations for remote and regional earthquakes for the first quarter of 2016 with an energy class from 6 to 10.

scholarly journals Tectonic structure and development of the “depression/ uplift” transition zones, Northern Tien Shan

2020 ◽  
Vol 65 (4) ◽  
Author(s):  
Eugeny S. Przhiyalgovskii ◽  
◽  
Yuriy A. Morozov ◽  
Mikhail G. Leonov ◽  
Anatoliy K. Rybin ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Lateral Pressure ◽  
Sedimentary Cover ◽  
Tectonic Setting ◽  
Structural Features ◽  
Tien Shan ◽  
Vertical Movements ◽  
Transition Zones ◽  
Basement Rocks ◽  
Northern Tien Shan

The article presents data on the structure of transition zones from areas of relative downwarping (intramountain depressions) to anticlinor uplifts dividing them. The geological and geophysical data obtained by the authors in recent years in different areas of the Northern Tien Shan are considering and discussing to compare the structure and tectonic evolution of key objects. A comparative analysis of the depression / uplift tectonic zones in different regions indicates a fundamental similarity in their structure. These areas of gradient vertical movements are zones of concentrated deformation. We described ensembles of structures formed at the same time in the sedimentary cover and in the basement rocks. Similar structural features are due to the common tectonic evolution of basins and ridges as parts of a unified activation structure of the Paleozoic folded belt. Over a long period of time, from the Oligocene to the Pliocene inclusive, the depressions of the Northern Tien Shan had developed under conditions of sedimentary subsidence, probably by the type of pool-apart structures in a latitudinally oriented region of plastic shear deformation. The relatively quiet tectonic setting of this stage is reflected in the lithological features of the sedimentary complexes. The next stage, which began about 3 Ma b.p., was marked not only by the emergence of a high-altitude relief and the accumulation of molasses, but also by a change of tectonic regime to transpression. The generally flexible bending of the foundation surface in the steep sides of the depressions, to some extent complicated by uplifts, was accompanied by the formation of extensive detachments and thrust-folded structural ensembles in the sedimentary cover of the depressions. Contrary to popular point of view volumes of disintegrated basement rocks demonstrate significant plasticity. The lateral pressure of the side ledges inside the sedimentary cover was transmitted for many kilometers towards the depression’s center. At the same time, contrary to traditional ideas, the volumes of disintegrated rocks of the basement demonstrate significant plasticity, while the lateral pressure of the side ledges was transmitted for many kilometers into the depressions inside the sedimentary cover.

scholarly journals The capabilities of analyzing the seismo-electromagnetic satellite CSES-01 data for monitoring of seismic activity of the Northern Tien Shan

2021 ◽  
Vol 929 (1) ◽  
pp. 012017
Author(s):  
K S Nepeina
Keyword(s):  
Space Weather ◽  
Tien Shan ◽  
Measuring Instruments ◽  
Research Station ◽  
Strong Earthquakes ◽  
Magnetotelluric Soundings ◽  
Future Technologies ◽  
The Relationship ◽  
Random Nature ◽  
Northern Tien Shan

Abstract The relationship between space weather and earthquakes occurring in seismically active areas with the seismo-electromagnetic satellite CSES-01 data are observed. The study assumes the presence of possible ionospheric precursors of strong earthquakes. The sets of measuring instruments of the satellite and data are considered. Subsequently, to prove the non-random nature of the space weather effects, the results of ground-based geomagnetic or electromagnetic observations should be used, for example, magnetotelluric soundings (MTS). Stationary and regime points of the MTS network of the Research Station RAS in Bishkek (RS RAS) are suitable for these purposes in the Northern Tien Shan. The MTS data are presented in the form of hourly frequency-time series with system rotation from 0° to 180°. To obtain information on earthquakes, it is proposed to use data from the NEIC or ISC seismic catalog, since they aggregate data from regional catalogs, including the KNET seismological network maintained by the RS RAS. It is concluded that it is necessary to select the CSES-01 trajectories and times of flight over the territory of Kyrgyzstan and download the electric field detector (EFD) data. The results of comparing satellite and ground-based observations can be used in future technologies for short-term earthquake prediction.

Array magnetotelluric soundings in the active seismic area of Northern Tien Shan

2008 ◽  
Vol 49 (5) ◽  
pp. 337-349 ◽  
Author(s):  
A.K. Rybin ◽  
V.V. Spichak ◽  
V.Yu. Batalev ◽  
E.A. Bataleva ◽  
V.E. Matyukov
Keyword(s):  
Tien Shan ◽  
Magnetotelluric Soundings ◽  
Seismic Area ◽  
Northern Tien Shan

Computational technologies in seismological research (on the example of KNET, Northern Tian Shan)

2020 ◽  
Author(s):  
N.A. Sycheva
Keyword(s):  
Graduate Students ◽  
Seismic Data ◽  
Test Site ◽  
Tien Shan ◽  
Strained State ◽  
Determination Of Parameters ◽  
Northern Tien Shan ◽  
Young Researchers

The results of long-term seismological investigations have been represented in the manuscript, which were obtained by the data of the seismological network KNET established in 1991 in Northern Tien Shan. Use of various tools for processing of the obtained seismic data allowed solving a number of seismological problems, such as assessment of kinematic and dynamic parameters of earthquakes, determination of parameters of the stress – strained state of the of the crust. The new results describing in details the determinations of various indicators of seismicity in the territory of the Bishkek geodynamic test site, Northern Tien Shan have been presented. The book will be useful to the young researchers and graduate students working in the field of Earth Sciences.

Sign in / Sign up

Export Citation Format

Share Document