scholarly journals Geoelectrical structure and monitoring in fault zones of Uimon depression in Gorny Altai region using electromagnetic methods

2021 ◽  
Vol 929 (1) ◽  
pp. 012025
Author(s):  
N N Nevedrova ◽  
A M Sanchaa ◽  
I O Shaparenko
Keyword(s):  
Fault Zones ◽  
Northwestern Part ◽  
Altai Region ◽  
Electromagnetic Methods ◽  
Gorny Altai ◽  
Geoelectrical Structure ◽  
Electrical Prospecting

Abstract In this paper we present the results of our studies of sections of the Uimon basin in Gorny Altai (Russia) using a complex of electrical prospecting methods. The areas of Baratal Formation at the surface have been investigated. This areas explored in order to understand the stages of formation of the depression. In addition, the possibilities of the electrotomography method for regular observations in seismoactive regions are shown. Comparison of the amplitudes of the resistivity variations based on repeated ERT measurements in different zones of the Terekta fault indicates the activity of its eastern part, which is expressed in significant resistivity variations exceeding 100%. At the same time, the variations in the northwestern part of the fault, reaching 15% on average, are many times smaller.

Geoelectrical Models of Fault Zones in the Gorny Altai Region

2019 ◽  
pp. 135-144
Author(s):  
Nina Nevedrova ◽  
Sergey Babushkin ◽  
Aydisa Sanchaa ◽  
Ilya Shaparenko ◽  
Alexander Shalaginov
Keyword(s):  
Fault Zones ◽  
Altai Region ◽  
Gorny Altai

scholarly journals MODERN MOVEMENTS OF THE CRUST SURFACE IN GORNY ALTAI FROM GPS DATA

2019 ◽  
Vol 10 (1) ◽  
pp. 123-146
Author(s):  
V. Yu. Timofeev ◽  
D. G. Ardyukov ◽  
A. V. Timofeev ◽  
E. V. Boiko
Keyword(s):  
Anomalous Behavior ◽  
Strike Slip ◽  
Elastic Model ◽  
Displacement Fields ◽  
Epicentral Zone ◽  
Lateral Strike Slip ◽  
Altai Region ◽  
Gorny Altai ◽  
Vertical Fault ◽  
The Right

In 2000–2017, the GPS technology was first applied to study inter-seismic, co-seismic and post-seismic processes in the crust of the Altai Mountains (Gorny Altai). Our study aims at investigating the fields of displacement and deformation in the Gorny Altai region as a part of Asia.The 3D displacement fields are reconstructed for the period before the M 7.3 Chuya earthquake that occurred in the southern sector of the Altai GPS network (49° to 55°N, and 81° to 89°E)on 27 September 2003.Anomalous behavior features are discovered in the displacement orientations, as well as in the distribution of velocities and deformation in the zone of the future earthquake.The spatial displacement pattern defined for the period of co-seismic displacements corresponds to the right-lateral strike-slip along the vertical fault. The fault depth is estimated using the elastic model and the experimental data (change in displacement from 0.30 m to 0.02 m at the distances of 14 km and 84 km from the fault, respectively); it amounts to 8–10 km.The co-seismic deformation field is investigated.In the post-seismic stage (2004–2017), displacements revealedin the epicentral zone show the right-lateral strike-slip along the fault at the rate of 2 mm/yr. Therefore, two-layer viscoelastic models can be considered. The estimated viscosity of the lower crust ranges from 6×1019to 3×1020Pa×s, and the elastic upper crust thickness is 25 km. Analyzed are modern movements in the Gorny Altai region outside the Chuya earthquake area.The results of our study show that modern horizontal displacements occur in the NNW direction at the rate of 1.1 mm/yr, which is twice lower than the displacement rate before the earthquake.

scholarly journals BLOCK STRUCTURE OF THE SOUTHERN KURAI BASIN OF GORNY ALTAI ACCORDING TO GEOELECTRIC DATA COMPARED TO THE DISTRIBUTION OF EARTHQUAKE EPICENTERS

2019 ◽  
Vol 10 (1) ◽  
pp. 167-180 ◽  
Author(s):  
A. M. Sanchaa ◽  
N. N. Nevedrova ◽  
P. V. Ponomarev
Keyword(s):  
Seismic Events ◽  
Data Inversion ◽  
Transient Electromagnetic ◽  
Electromagnetic Methods ◽  
Seismological Data ◽  
Gorny Altai ◽  
Electrical Sounding ◽  
Fault Structures ◽  
Field Database ◽  
Geoelectric Data

The Kurai Basin of Gorny Altai is located in the area of high seismic activity, which is involved in the focal zone of the 2003 M7.3 Chuya earthquake. Its aftershock process has not ceased yet, and shows the likelihood of major seismic events. The seismic monitoring records of the last 15 years after the devastating earthquake show the state of stress in the basin. A comprehensive field database has been consolidated from the studies of direct and alternating currents by electromagnetic methods, including transient electromagnetic sounding, vertical electrical sounding, and electric field tomography. Using a combination of the research techniques and the method of interpretation based on data inversion, it becomes possible to select optimal models, ensure higher reliability, and improve the contents of the study. The available seismological data are used to identify the zones of concentration of seismic events in the southern mountain frame of the Kurai Basin. Our study aims to determine and clarify the geoelectric structure of the southern troughs. The first section of the Southwestern trough is constructed, and the latitudinal fault boundaries of the Eshtykel graben are confirmed. A comparison of electromagnetic and seismic data for 2015 shows that the earthquake epicenters were mainly confined to the submeridional fault zones. In our study of the Southwestern trough, it is established that most of the earthquakes concentrated in active fault structures separating the blocks of varying depths, which are identified from the geoelectric data. The southern piedmont troughs of the Kurai Basin are cut by numerous faults of latitudinal and submeridional strikes. 

Results of monitoring different structures by electrotomography method in difficultly constructed areas

2020 ◽  
Author(s):  
Ilya O. Shaparenko ◽  
◽  
Nina N. Nevedrova ◽  
Keyword(s):  
Fault Zones ◽  
Geological Features ◽  
Gorny Altai

The paper considers the results of a study by the method of electrotomography of complex sections of Gorny Altai with different geological features. Geoelectrical sections were constructed, the nature of the change in the parameters of fault zones was determined based on the monitoring results.

Plant Morphofunctional Response to Environmental Changes in Active Fault Zones of the Kurai Ridge (Gorny Altai)

2020 ◽  
Vol 56 (8) ◽  
pp. 773-798
Author(s):  
I. G. Boyarskikh ◽  
A. R. Agatova ◽  
A. I. Syso ◽  
A. I. Klyuchevskaya
Keyword(s):  
Active Fault ◽  
Environmental Changes ◽  
Fault Zones ◽  
Gorny Altai

Variations d'épaisseur du Cambrien moyen en Meseta marocaine occidentale: signification géodynamique des données de surface et de subsurface

1988 ◽  
Vol 25 (12) ◽  
pp. 2104-2117 ◽  
Author(s):  
Christine Bernardin ◽  
Jean-Jacques Cornée ◽  
Michel Corsini ◽  
Stéphane Mayol ◽  
Jacques Muller ◽  
...  
Keyword(s):  
Field Data ◽  
Fault Zones ◽  
Northwestern Part ◽  
Early Cambrian ◽  
Middle Cambrian ◽  
Late Precambrian ◽  
Intracontinental Rift ◽  
Late Evolution ◽  
Geophysical Investigations

The western part of the Moroccan Meseta contains thick Middle Cambrian terrigenous deposits, in places 7000 m thick. Field data and geophysical investigations indicate subsident grabens controlled by major N30°E and N60°E fault zones on the northwestern part of the African shield. These grabens correspond to the late evolution of an intracontinental rift that originated during Late Precambrian and Early Cambrian time and can be considered evidence of the opening of the Iapetus paleo-ocean in Morocco.

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