Geoelectric section of the Central Tien Shan: Analysis of magnetotelluric and magnetovariational responses along the Naryn geotraverse

Berdichevsky, Mark N.; Sokolova, E. Yu.; Варенцов, И.М.; Рыбин, А. В.; Baglaenko, N.V.; Batalev, V. Yu.; Golubtsova, N.; Matyukov, V. E.; Pushkarev, P. Yu.

doi:10.1134/s1069351310080057

Cited by 19 publications

(2 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For the H responses dimensionality analysis was performed following similar criteria to that used by Berdichevsky et al (2010b), plotting the variations of the H responses: H-I, where I is the identity matrix. In this case 1-D structures are represented by dots (Phi max = Phi min = 0), 2-D structures by lines (Phi max > Phi min = 0) and 3-D structures by ellipses (Phi max ≥ Phi min = 0).…”

Section: Dimensionality Analysismentioning

confidence: 99%

The advantages of complementing MT profiles in 3-D environments with geomagnetic transfer function and interstation horizontal magnetic transfer function data: results from a synthetic case study

Campanyà¹,

Ogaya²,

Jones³

et al. 2016

Geophys. J. Int.

View full text Add to dashboard Cite

: The advantages of complementing MT profiles in 3-D environments with geomagnetic transfer function and interstation horizontal magnetic transfer function data: results from a synthetic case study. -Geophysical Journal International, 207, 3, pp. 1818-1836 S U M M A R YAs a consequence of measuring time variations of the electric and the magnetic field, which are related to current flow and charge distribution, magnetotelluric (MT) data in 2-D and 3-D environments are not only sensitive to the geoelectrical structures below the measuring points but also to any lateral anomalies surrounding the acquisition site. This behaviour complicates the characterization of the electrical resistivity distribution of the subsurface, particularly in complex areas. In this manuscript we assess the main advantages of complementing the standard MT impedance tensor (Z) data with interstation horizontal magnetic tensor (H) and geomagnetic transfer function (T) data in constraining the subsurface in a 3-D environment beneath a MT profile. Our analysis was performed using synthetic responses with added normally distributed and scattered random noise. The sensitivity of each type of data to different resistivity anomalies was evaluated, showing that the degree to which each site and each period is affected by the same anomaly depends on the type of data. A dimensionality analysis, using Z, H and T data, identified the presence of the 3-D anomalies close to the profile, suggesting a 3-D approach for recovering the electrical resistivity values of the subsurface. Finally, the capacity for recovering the geoelectrical structures of the subsurface was evaluated by performing joint inversion using different data combinations, quantifying the differences between the true synthetic model and the models from inversion process. Four main improvements were observed when performing joint inversion of Z, H and T data: (1) superior precision and accuracy at characterizing the electrical resistivity values of the anomalies below and outside the profile; (2) the potential to recover high electrical resistivity anomalies that are poorly recovered using Z data alone; (3) improvement in the characterization of the bottom and lateral boundaries of the anomalies with low electrical resistivity; and (4) superior imaging of the horizontal continuity of structures with low electrical resistivity. These advantages offer new opportunities for the MT method by making the results from a MT profile in a 3-D environment more convincing, supporting the possibility of high-resolution studies in 3-D areas without expending a large amount of economical and computational resources, and also offering better resolution of targets with high electrical resistivity.

show abstract

Section: Dimensionality Analysismentioning

confidence: 99%

The advantages of complementing MT profiles in 3-D environments with geomagnetic transfer function and interstation horizontal magnetic transfer function data: results from a synthetic case study

Campanyà¹,

Ogaya²,

Jones³

et al. 2016

Geophys. J. Int.

View full text Add to dashboard Cite

show abstract

“…Общим для рассматриваемых тектонических сегментов является то, что наиболее ярко выраженные проводящие объекты геоэлектрических моделей, построенных по результатам магнитотеллурических зондирований [Batalev et al, 1989[Batalev et al, , 1993Bielinski et al, 2003;Bataleva et al, 2006Bataleva et al, , 2013Berdichevsky et al, 2010;Makarov et al, 2010;Rybin et al, 2008;Rybin, 2011;Trapeznikov et al, 1997], совпадают с низкодобротными зонами [Aptikaeva, 2018;Aptikaeva et al, 1996]. Это может свидетельствовать о флюидонасыщении выявленных проводников и волноводов литосферы Тянь-Шаня, поскольку низкоскоростные аномалии P-волн также соответствуют зонам низкой добротности.…”

Section: рисunclassified

Volumetric and Spatial Segmentation of the Tien Shan Lithosphere According to Geophysical Data

Рыбин¹,

Баталева²,

Непеина³

et al. 2021

Geodin. tektonofiz.

Self Cite

View full text Add to dashboard Cite

This article consolidates the results of studying the deep structure of the lithosphere of the Central Tien Shan, which aimed to identify the main tectonic elements in its geophysical models. We have compared the structural and geological data with the information on the deep structure obtained by geophysical methods and from the positions of earthquake hypocenters in the study area. According to geological concepts, the Tien Shan orogenic belt is characterized by longitudinal and transverse segmentation. The boundaries of the Northern, Middle, Southern Western and Eastern segments of the Tien Shan are deep-seated fault structures. In deep faults and channels of heat and mass transfer, endogenous processes are localized. High-velocity, geoelectrical and thermal models consider such faults and channels as contrasting objects that can be referred to as indicators of these processes.Our analysis of the locations of earthquake hypocenters from NNC, KNET, CAIIG, KRNET, SOME catalogues shows that seismic events are strongly confined to the fault zones and the boundaries of large blocks. A correlation between the anomalies of geophysical fields suggests the degree of inheritance of tectonic structures and the boundaries of the main tectonic segments of the Tien Shan. To compare the crustal and upper mantle heterogeneities reflected in different geophysical fields, we have analyzed seismic tomographic sections based on volumetric seismotomographic models geoelectric and velocity sections along profiles across the main tectonic elements of the study area. The sections are used to identify the zones with relatively low (i.e. reduced) seismic wave velocities and detect the deep-seated longitudinal segmentation of the folded belt. Objects showing anomalous seismic wave velocities are found in the seismotomographic sections at all the depths under consideration. The most contrasting differences in the velocities of P- and S-waves are typical of the depths of 0-5 km and 50-65 km, showing the most clearly observed Northern, Southern and Western segments of the Tien Shan. In general, the velocities of P- and S-waves at the Northern Tien Shan are higher than those at the Middle and Southern segments. We have analyzed the distribution of geoelectric heterogeneities identified from magnetotelluric sounding data in order to determine the boundaries of the main tectonic elements that are considered as the zones of increased electrical conductivity confined to the boundaries of the fault structures. The distribution of earthquake epicenters clearly reflects the segmentation of the Tien Shan into the Northern, Middle and Southern segments and shows the Western and Eastern Tien Shan relative to the Talas-Fergana fault. Ourstudies of the crust and the upper mantle of the Tien Shan have confirmed that the abovementioned tectonic segments have differences in their deep structures Based on a comprehensive analysis of the study results, we can qualitatively identify a relationship between the distribution of the velocity and geoelectric heterogeneities in the crust and upper mantle, seismicity and the stress-strain state of the crust.

show abstract

Evaluation of Hypocenters Distribution Based on the Geoelectric Models in the Tien Shan Earthquake-Prone Areas

Непеина

Баталева

2022

Springer Proceedings in Earth and Environmental Sciences

View full text Add to dashboard Cite

Geoelectric section of the Central Tien Shan: Analysis of magnetotelluric and magnetovariational responses along the Naryn geotraverse

Cited by 19 publications

References 8 publications

The advantages of complementing MT profiles in 3-D environments with geomagnetic transfer function and interstation horizontal magnetic transfer function data: results from a synthetic case study

The advantages of complementing MT profiles in 3-D environments with geomagnetic transfer function and interstation horizontal magnetic transfer function data: results from a synthetic case study

Volumetric and Spatial Segmentation of the Tien Shan Lithosphere According to Geophysical Data

Evaluation of Hypocenters Distribution Based on the Geoelectric Models in the Tien Shan Earthquake-Prone Areas

Contact Info

Product

Resources

About