The central Indian Ocean displays one of the most perplexing intra-plate deformations in an oceanic realm. Despite several studies attempting to explore this intriguing phenomenon, understanding about its structural style and spatiotemporal genesis is still debated. Earlier geophysical and deep-sea drilling studies proposed the late Miocene onset of extensive crustal deformation. Subsequent geophysical studies, however, speculated that parts of the deformation may have begun significantly earlier (c.a. 15.4–13.9 Ma) consequent upon contemporaneous dynamics of the India-Eurasia convergence. Alternative hypotheses argue about the crucial role played by temporal variations in the rotational motion of the India-Somalia-Capricorn plates. Here we examine new deep penetrating multi-channel seismic reflection data from the central Indian Ocean region to gather the style and extent of structural deformation in this region. We explore plausible mechanisms and estimate the onset of extensive intra-plate deformation. Based on seismic-stratigraphic interpretation and cumulative fault-throw analyses of new regional seismic profiles, our study confirms that extensive faulting occurred during the early Miocene period across the CIDZ. We document that an average of 40% of faults were activated around or before early Miocene time, showing maximum throw at a regional unconformity dating to 17–18 Ma. We also identify distinct categories of deformation manifested in these faults. While our findings endorse significantly prior to the late Miocene time of onset of deformation, new subsurface images offer much-improved constraints on prominent stratigraphic and structural variations.
{"title":"Quantifying Structural Deformation History in the Central Indian Ocean","authors":"Rahul Yadav, Dhananjai K. Pandey, Lachit Singh Ningthoujam, Sanjay Singh Negi","doi":"10.1134/S106935132306023X","DOIUrl":"10.1134/S106935132306023X","url":null,"abstract":"<p>The central Indian Ocean displays one of the most perplexing intra-plate deformations in an oceanic realm. Despite several studies attempting to explore this intriguing phenomenon, understanding about its structural style and spatiotemporal genesis is still debated. Earlier geophysical and deep-sea drilling studies proposed the late Miocene onset of extensive crustal deformation. Subsequent geophysical studies, however, speculated that parts of the deformation may have begun significantly earlier (c.a. 15.4–13.9 Ma) consequent upon contemporaneous dynamics of the India-Eurasia convergence. Alternative hypotheses argue about the crucial role played by temporal variations in the rotational motion of the India-Somalia-Capricorn plates. Here we examine new deep penetrating multi-channel seismic reflection data from the central Indian Ocean region to gather the style and extent of structural deformation in this region. We explore plausible mechanisms and estimate the onset of extensive intra-plate deformation. Based on seismic-stratigraphic interpretation and cumulative fault-throw analyses of new regional seismic profiles, our study confirms that extensive faulting occurred during the early Miocene period across the CIDZ. We document that an average of 40% of faults were activated around or before early Miocene time, showing maximum throw at a regional unconformity dating to 17–18 Ma. We also identify distinct categories of deformation manifested in these faults. While our findings endorse significantly prior to the late Miocene time of onset of deformation, new subsurface images offer much-improved constraints on prominent stratigraphic and structural variations.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-28DOI: 10.1134/S1069351323060101
V. N. Krizskii, P. N. Aleksandrov
This work is a continuation of the authors’ research on solving inverse problems of mathematical geophysics in a linear formulation. Unlike previous works, where the solution was built on the basis of volumetric integral equations, boundary integral representations and emerging boundary integral equations are used here to solve the inverse coefficient problem of geoelectrics to find the constant electrical conductivity of a local isotropic inclusion, located in a piecewise-constant electrical conductivity isotropic enclosing medium.
{"title":"On Determination of the Electrical Conductivity of a Local Inclusion of a Piecewise-Сonstant Isotropic Medium","authors":"V. N. Krizskii, P. N. Aleksandrov","doi":"10.1134/S1069351323060101","DOIUrl":"10.1134/S1069351323060101","url":null,"abstract":"<p>This work is a continuation of the authors’ research on solving inverse problems of mathematical geophysics in a linear formulation. Unlike previous works, where the solution was built on the basis of volumetric integral equations, boundary integral representations and emerging boundary integral equations are used here to solve the inverse coefficient problem of geoelectrics to find the constant electrical conductivity of a local isotropic inclusion, located in a piecewise-constant electrical conductivity isotropic enclosing medium.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-28DOI: 10.1134/S1069351323060095
V. N. Koneshov, N. V. Drobyshev, R. A. Sermyagin, E. P. Razin’kova
This work is aimed at estimating the long-term continuing measurements of the acceleration of gravity at the Ledovo fundamental gravity station and first order stations of the gravimetric network of the Russian Federation. The observations are carried out by absolute gravimeters beginning from the mid-1970s to the present time. It is shown that the observed value of the acceleration of gravity at the Ledovo station has a tendency to decrease during last 45 years; according to our estimates, the value decreased by 32 µGal. The measurements carried out at first order gravity stations in Russia after renewal of network maintenance are compared with measurements carried out in the 1980s.
{"title":"Results of Estimating the Absolute Gravimetric Measurements at the Ledovo Fundamental Gravity Station and on the First Order Gravimetric Network of Russia","authors":"V. N. Koneshov, N. V. Drobyshev, R. A. Sermyagin, E. P. Razin’kova","doi":"10.1134/S1069351323060095","DOIUrl":"10.1134/S1069351323060095","url":null,"abstract":"<p>This work is aimed at estimating the long-term continuing measurements of the acceleration of gravity at the Ledovo fundamental gravity station and first order stations of the gravimetric network of the Russian Federation. The observations are carried out by absolute gravimeters beginning from the mid-1970s to the present time. It is shown that the observed value of the acceleration of gravity at the Ledovo station has a tendency to decrease during last 45 years; according to our estimates, the value decreased by 32 µGal. The measurements carried out at first order gravity stations in Russia after renewal of network maintenance are compared with measurements carried out in the 1980s.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-28DOI: 10.1134/S1069351323060228
R. E. Tatevossian, N. G. Mokrushina, A. N. Ovsyuchenko, A. S. Larkov
In this paper, we determine the location of the hypocenter and the magnitude of the earthquake of September 11/23, 1888 based on macroseismic data published in the Russian periodic in Russian, Armenian, and Georgian languages. Calculations showed that the magnitude of the earthquake was previously significantly underestimated, due to which it was not included in the catalog of strong earthquakes in the Caucasus test region (Shebalin and Tatevossian, 1997). The accuracy of the location of the hypocenter makes it possible to identify the active fault, with which the source of the 1888 earthquake is associated. The earthquake with Mw = 6.6 that occurred almost 100 years later confirms the long-term activity of the Western branch of the East Anatolian fault zone.
{"title":"Historical Earthquake on the North-Eastern Extension of the East Anatolian Fault","authors":"R. E. Tatevossian, N. G. Mokrushina, A. N. Ovsyuchenko, A. S. Larkov","doi":"10.1134/S1069351323060228","DOIUrl":"10.1134/S1069351323060228","url":null,"abstract":"<p>In this paper, we determine the location of the hypocenter and the magnitude of the earthquake of September 11/23, 1888 based on macroseismic data published in the Russian periodic in Russian, Armenian, and Georgian languages. Calculations showed that the magnitude of the earthquake was previously significantly underestimated, due to which it was not included in the catalog of strong earthquakes in the Caucasus test region (Shebalin and Tatevossian, 1997). The accuracy of the location of the hypocenter makes it possible to identify the active fault, with which the source of the 1888 earthquake is associated. The earthquake with <i>M</i><sub>w</sub> = 6.6 that occurred almost 100 years later confirms the long-term activity of the Western branch of the East Anatolian fault zone.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-28DOI: 10.1134/S1069351323060162
V. F. Pisarenko, A. A. Skorkina, T. A. Rukavishnikova
This study is devoted to application of some new statistical methods to analysis of the spatial structure of the seismic field in a seismically active region in the neighborhood of Japan bounded by the following coordinates: 28°–50° north latitude, 130°–150° east longitude. The estimates of the seismic flux were obtained by using the k-nearest neighbors method for the magnitude interval m ≥ 5.2. The highest values of seismic flux intensity of about 10–4(frac{1}{{{text{year}}{kern 1pt} - {kern 1pt} {text{k}}{{{text{m}}}^{{text{2}}}}}}) are located at depths of down to 100 km and manifest themselves in the neighborhood of the Tohoku megathrust earthquake. The spatial resolution of the intensity estimates is ranging from 33–50 km in the regions with a high intensity to 100 km and larger in the zones with a weak intensity. It has been shown that the seismic filed parameters—intensity λ, slope of the magnitude–frequency graph β, maximum possible magnitude m1—have different scales of their spatial variability and, thus, it is necessary to apply different scales of spatial averaging to them. Based on the Gutenberg—Richter truncated distribution model, the estimates are obtained for the slope of the magnitude–frequency graph (b‑value) and the upper boundary of the distribution m1. An original method is proposed for determining the optimal averaging radius for an arbitrary cell of the space grid. The method is based on the use of the statistical coefficient of variation of the corresponding parameter. For the considered region, the estimate of the maximum possible magnitude Мmax= 9.60 ( pm ) 0.41 was obtained with consideration of the correction for bias.
{"title":"Application of New Statistical Methods to Estimation of the Seismicity Field Parameters by an Example of the Japan Region","authors":"V. F. Pisarenko, A. A. Skorkina, T. A. Rukavishnikova","doi":"10.1134/S1069351323060162","DOIUrl":"10.1134/S1069351323060162","url":null,"abstract":"<p>This study is devoted to application of some new statistical methods to analysis of the spatial structure of the seismic field in a seismically active region in the neighborhood of Japan bounded by the following coordinates: 28°–50° north latitude, 130°–150° east longitude. The estimates of the seismic flux were obtained by using the <i>k-</i>nearest neighbors method for the magnitude interval <i>m</i> ≥ 5.2. The highest values of seismic flux intensity of about 10<sup>–4</sup> <span>(frac{1}{{{text{year}}{kern 1pt} - {kern 1pt} {text{k}}{{{text{m}}}^{{text{2}}}}}})</span> are located at depths of down to 100 km and manifest themselves in the neighborhood of the Tohoku megathrust earthquake. The spatial resolution of the intensity estimates is ranging from 33–50 km in the regions with a high intensity to 100 km and larger in the zones with a weak intensity. It has been shown that the seismic filed parameters—intensity λ, slope of the magnitude–frequency graph β, maximum possible magnitude <i>m</i><sub>1</sub>—have different scales of their spatial variability and, thus, it is necessary to apply different scales of spatial averaging to them. Based on the Gutenberg—Richter truncated distribution model, the estimates are obtained for the slope of the magnitude–frequency graph (<i>b</i>‑value) and the upper boundary of the distribution <i>m</i><sub>1</sub>. An original method is proposed for determining the optimal averaging radius for an arbitrary cell of the space grid. The method is based on the use of the statistical coefficient of variation of the corresponding parameter. For the considered region, the estimate of the maximum possible magnitude <i>М</i><sub>max</sub> <i>=</i> 9.60 <span>( pm )</span> 0.41 was obtained with consideration of the correction for bias.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-28DOI: 10.1134/S1069351323060198
D. A. Simonov, V. S. Zakharov
In this paper, we kinematically analyze the movements of plates and blocks of the region of southeastern Turkey, where strong earthquakes occurred on February 6, 2023, based on a homogeneous database of displacement velocities of GNSS permanent monitoring stations. Along the East Anatolian fault zone from 2008 to 2018, the Arabian Plate was established to shift relative to the Anatolian Plate, which corresponds to a left shift (without a normal component) at a rate from 1 cm/yr in the eastern part to 0.8 cm/yr in the western part. Along the Chardak fault, displacements corresponding to the left shift occurred at a rate of less than 0.7 cm/year. The revealed kinematics is confirmed by focal mechanisms and cosesismic displacements of the studied earthquakes. The M7.5 earthquake that occurred directly on the Chardak fault is not an aftershock of the M7.8 earthquake, but is a relatively independent event. An analysis of the seismic regime shows that the stresses on the East Anatolian fault after the main M7.8 event are relieved by the first large latitudinal fault zone (the Chardak fault). The results of our study suggest that the counterclockwise rotation of the Anatolian and Arabian plates associated with the opening of the Red Sea Rift is most likely decisive for the general kinematics of the plates in the region.
{"title":"Preliminary Seismo-Tectonic Analysis of the Catastrophic Earthquake in South-Eastern Turkey on February 6, 2023","authors":"D. A. Simonov, V. S. Zakharov","doi":"10.1134/S1069351323060198","DOIUrl":"10.1134/S1069351323060198","url":null,"abstract":"<p>In this paper, we kinematically analyze the movements of plates and blocks of the region of southeastern Turkey, where strong earthquakes occurred on February 6, 2023, based on a homogeneous database of displacement velocities of GNSS permanent monitoring stations. Along the East Anatolian fault zone from 2008 to 2018, the Arabian Plate was established to shift relative to the Anatolian Plate, which corresponds to a left shift (without a normal component) at a rate from 1 cm/yr in the eastern part to 0.8 cm/yr in the western part. Along the Chardak fault, displacements corresponding to the left shift occurred at a rate of less than 0.7 cm/year. The revealed kinematics is confirmed by focal mechanisms and cosesismic displacements of the studied earthquakes. The <i>M</i>7.5 earthquake that occurred directly on the Chardak fault is not an aftershock of the <i>M</i>7.8 earthquake, but is a relatively independent event. An analysis of the seismic regime shows that the stresses on the East Anatolian fault after the main <i>M</i>7.8 event are relieved by the first large latitudinal fault zone (the Chardak fault). The results of our study suggest that the counterclockwise rotation of the Anatolian and Arabian plates associated with the opening of the Red Sea Rift is most likely decisive for the general kinematics of the plates in the region.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-28DOI: 10.1134/S106935132306006X
F. Z. Feygin, A. V. Guglielmi
This paper is devoted to the 80th anniversary of the discovery of Alfven waves, which play an important role in physics, radiophysics, astrophysics, and Earth physics. The emphasis is on the ponderomotive redistribution of plasma in the Earth’s magnetosphere under the action of Alfven and ion-cyclotron waves. At relatively small distances from the Earth, the ponderomotive force is buoyant, i.e., is directed upwards, regardless of whether an Alfven wave propagates towards the Earth or away from it. In the near-equatorial zone of the central regions of magnetosphere, waves in the Pc 1 range push the plasma to the minimum of geomagnetic field, so that a maximum of plasma density arises on the equator at sufficiently high wave intensity. A bifurcation occurs at the magnetosphere’s periphery, and the maximum is split into two maxima, the distance between which increases while moving away from the Earth. The polar wind, acceleration of heavy ions, and fictitious nonlinearity of the surface impedance of the Earth’s crust are also briefly discussed.
{"title":"Ponderomotive Forces of Alfven Waves in the Earth’s Magnetosphere","authors":"F. Z. Feygin, A. V. Guglielmi","doi":"10.1134/S106935132306006X","DOIUrl":"10.1134/S106935132306006X","url":null,"abstract":"<p>This paper is devoted to the 80th anniversary of the discovery of Alfven waves, which play an important role in physics, radiophysics, astrophysics, and Earth physics. The emphasis is on the ponderomotive redistribution of plasma in the Earth’s magnetosphere under the action of Alfven and ion-cyclotron waves. At relatively small distances from the Earth, the ponderomotive force is buoyant, i.e., is directed upwards, regardless of whether an Alfven wave propagates towards the Earth or away from it. In the near-equatorial zone of the central regions of magnetosphere, waves in the Pc 1 range push the plasma to the minimum of geomagnetic field, so that a maximum of plasma density arises on the equator at sufficiently high wave intensity. A bifurcation occurs at the magnetosphere’s periphery, and the maximum is split into two maxima, the distance between which increases while moving away from the Earth. The polar wind, acceleration of heavy ions, and fictitious nonlinearity of the surface impedance of the Earth’s crust are also briefly discussed.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-28DOI: 10.1134/S1069351323060034
I. P. Babayants, A. A. Baryakh, V. O. Mikhailov, E. P. Timoshkina, M. S. Volkova, S. A. Khairetdinov
The paper presents the results of the processing of satellite radar images acquired by the TerraSAR-X satellite using the persistent scatterer method for analyzing the subsidence of the earth’s surface over potash mines in the city of Berezniki, Perm Krai. A sequence of processing procedures in the GAMMA Software package (Gamma Remote Sensing AG, Switzerland) is presented, which showed good results in the conditions of this territory. A comparison is made with the results obtained earlier by summation of interferograms. In contrast to the methods of persistent scatterers, the summation is performed without analyzing displacements in time. The noisy time series obtained by the summation are not rejected, so the displacement maps cover the study area more evenly. In the persistent scatterer method, the time series is analyzed using a variety of criteria, so the subsidence rates are estimated more reliably. In the areas where the results were obtained by summation and the persistent scatterer method, the subsidence rates are in good agreement. The persistent scatterer method has made it possible to estimate displacements in certain areas separated by vast incoherent woodlands, on which interferograms lose their coherence. At the same time, a new subsidence area was identified with an average rate of subvertical displacements up to 75 mm/year and, in some areas, up to 100 mm/year, which, according to data for 2020 and 2018, was not detected. The subsidence here should be clarified based on the images for subsequent years or using surface thechniques. The time series also show the deceleration of subsidence in spring on persistent scatterers located on buildings and infrastructure. We associate the total spring deceleration of subsidence by 3–5 cm not with underground but with seasonal factors, specifically with the heating of buildings in the spring. Other reasons are also possible, but the main one is that, in areas with a moderate subsidence rate, this effect can lead to some underestimation of the average subsidence rate. A detailed study of the time series for subsidence makes it possible to identify areas requiring special attention. Most of the subsidence occurs more or less evenly; in a significant part of the territory, the subsidence rate in 2021 has decreased. This indicates the effectiveness of the measures taken to protect the ground infrastructure. Within the city area, the acceleration of subsidence was found only at the beginning of Lenin Avenue. SAR interferometry is an effective tool for studying subsidence processes in the city of Berezniki. This method significantly complements geodetic works, since it provides data on vast areas that cannot be covered by detailed ground measurements. In addition, part of the closed territories becomes dangerous for ground works, so there is no alternative to satellite technologies.
{"title":"Monitoring of Subsidence in Berezniki City (Perm Krai) by SAR Interferometry. Method of Persistent Scatterers","authors":"I. P. Babayants, A. A. Baryakh, V. O. Mikhailov, E. P. Timoshkina, M. S. Volkova, S. A. Khairetdinov","doi":"10.1134/S1069351323060034","DOIUrl":"10.1134/S1069351323060034","url":null,"abstract":"<p>The paper presents the results of the processing of satellite radar images acquired by the TerraSAR-X satellite using the persistent scatterer method for analyzing the subsidence of the earth’s surface over potash mines in the city of Berezniki, Perm Krai. A sequence of processing procedures in the GAMMA Software package (Gamma Remote Sensing AG, Switzerland) is presented, which showed good results in the conditions of this territory. A comparison is made with the results obtained earlier by summation of interferograms. In contrast to the methods of persistent scatterers, the summation is performed without analyzing displacements in time. The noisy time series obtained by the summation are not rejected, so the displacement maps cover the study area more evenly. In the persistent scatterer method, the time series is analyzed using a variety of criteria, so the subsidence rates are estimated more reliably. In the areas where the results were obtained by summation and the persistent scatterer method, the subsidence rates are in good agreement. The persistent scatterer method has made it possible to estimate displacements in certain areas separated by vast incoherent woodlands, on which interferograms lose their coherence. At the same time, a new subsidence area was identified with an average rate of subvertical displacements up to 75 mm/year and, in some areas, up to 100 mm/year, which, according to data for 2020 and 2018, was not detected. The subsidence here should be clarified based on the images for subsequent years or using surface thechniques. The time series also show the deceleration of subsidence in spring on persistent scatterers located on buildings and infrastructure. We associate the total spring deceleration of subsidence by 3–5 cm not with underground but with seasonal factors, specifically with the heating of buildings in the spring. Other reasons are also possible, but the main one is that, in areas with a moderate subsidence rate, this effect can lead to some underestimation of the average subsidence rate. A detailed study of the time series for subsidence makes it possible to identify areas requiring special attention. Most of the subsidence occurs more or less evenly; in a significant part of the territory, the subsidence rate in 2021 has decreased. This indicates the effectiveness of the measures taken to protect the ground infrastructure. Within the city area, the acceleration of subsidence was found only at the beginning of Lenin Avenue. SAR interferometry is an effective tool for studying subsidence processes in the city of Berezniki. This method significantly complements geodetic works, since it provides data on vast areas that cannot be covered by detailed ground measurements. In addition, part of the closed territories becomes dangerous for ground works, so there is no alternative to satellite technologies.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-26DOI: 10.1134/S1069351323050063
O. A. Meshcheryakova, R. N. Kurbanov, V. E. Pavlov
Abstract—The magnetic fabric of the reference Khonako-II (south Tajikistan), Beglitsa, and Chumbur-Kosa (Azov region) loess-paleosol sections was studied to reconstruct the paleowind directions during the Middle and Upper Pleistocene. The paleosols and loesses of the Khonako-II section represent a promising object for study of paleowinds. Our data indicate a prevailing ~ northwestward or ~northeastward wind directions during accumulation of the upper 40.8 m of the section. Thereby, a change from warm (pedocomplex 2) to cold (loess 2) epochs during the accumulation of the lower half of the studied sequence (end of the Middle Pleistocene) was accompanied by “switching” the predominant winds (from northwestern to northeastern ones), whereas accumulation of the upper part of the sequence was mainly controlled by winds of intermediate directions. The latter can be considered as evidence for the lesser contrast of wind rose during later epochs that were responsible for the formation of the upper part of the sequence. The study revealed that the magnetic fabric of loess and paleosol horizons of the Azov region sequences was deformed and cannot be used for paleowind reconstruction. It was demonstrated that sampling using plastic container technique widely applied in studying loess–paleosol deposits could led to the significant deformation of primary magnetic fabric.
{"title":"Reconstructions of Paleowind Directions in the Pleistocene: Evidence from the Anisotropy of Magnetic Susceptibility of the Loess–Paleosol Series of Tajikistan and the Azov Region","authors":"O. A. Meshcheryakova, R. N. Kurbanov, V. E. Pavlov","doi":"10.1134/S1069351323050063","DOIUrl":"10.1134/S1069351323050063","url":null,"abstract":"<div><div><p><b>Abstract</b>—The magnetic fabric of the reference Khonako-II (south Tajikistan), Beglitsa, and Chumbur-Kosa (Azov region) loess-paleosol sections was studied to reconstruct the paleowind directions during the Middle and Upper Pleistocene. The paleosols and loesses of the Khonako-II section represent a promising object for study of paleowinds. Our data indicate a prevailing ~ northwestward or ~northeastward wind directions during accumulation of the upper 40.8 m of the section. Thereby, a change from warm (pedocomplex 2) to cold (loess 2) epochs during the accumulation of the lower half of the studied sequence (end of the Middle Pleistocene) was accompanied by “switching” the predominant winds (from northwestern to northeastern ones), whereas accumulation of the upper part of the sequence was mainly controlled by winds of intermediate directions. The latter can be considered as evidence for the lesser contrast of wind rose during later epochs that were responsible for the formation of the upper part of the sequence. The study revealed that the magnetic fabric of loess and paleosol horizons of the Azov region sequences was deformed and cannot be used for paleowind reconstruction. It was demonstrated that sampling using plastic container technique widely applied in studying loess–paleosol deposits could led to the significant deformation of primary magnetic fabric.</p></div></div>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41082658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-26DOI: 10.1134/S1069351323050075
N. S. Nosikova, V. A. Pilipenko, S. L. Shalimov
The magnetic effects of two similar underwater earthquakes with magnitudes of 6.0 and 7.3, which occurred on March 16, 2022, were considered in (Adushkin et al., 2023). According to the data of INTERMAGNET magnetic observatories, these earthquakes were found to be accompanied (with a delay of ~55 min) by variations in the Earth’s magnetic field in the form of a train of quasi-periodic oscillations with an amplitude of ~2–8 nT and a period of ~30 min at distances of ~210 to ~3000 km from the epicenter. It was suggested in the aforementioned study that this magnetic effect is caused by a disturbance of the geodynamo as a result of the impact of seismic waves propagating deep into Earth. This interesting hypothesis requires a detailed discussion from different points of view. A more detailed analysis of the pattern of geomagnetic field disturbance at all latitudes, performed by us, leads to a conclusion that the found quasi-periodic disturbance is a mid-latitude response to auroral electrojet variations and is not related to the earthquake. According to our estimates, variations with a source at the core–mantle interface on a time scale less than one year cannot manifest themselves on the Earth’s surface at all.
在(Adushkin et al.,2023)中考虑了2022年3月16日发生的两次6.0级和7.3级类似水下地震的磁效应。根据INTERMAGNET磁观测站的数据,这些地震被发现伴随着地球磁场的变化(延迟约55分钟),在距离震中约210至3000公里的地方,以一系列振幅约为2–8 nT、周期约为30分钟的准周期振荡的形式出现。上述研究表明,这种磁效应是由传播到地球深处的地震波的影响引起的地球动力学扰动引起的。这个有趣的假设需要从不同的角度进行详细的讨论。我们对所有纬度的地磁场扰动模式进行了更详细的分析,得出的结论是,所发现的准周期性扰动是对极光电喷流变化的中纬度响应,与地震无关。根据我们的估计,在不到一年的时间尺度上,核幔界面来源的变化根本无法在地球表面表现出来。
{"title":"On the Magnetic Effects Caused by the Earthquake of March 16, 2022 in Japan","authors":"N. S. Nosikova, V. A. Pilipenko, S. L. Shalimov","doi":"10.1134/S1069351323050075","DOIUrl":"10.1134/S1069351323050075","url":null,"abstract":"<p>The magnetic effects of two similar underwater earthquakes with magnitudes of 6.0 and 7.3, which occurred on March 16, 2022, were considered in (Adushkin et al., 2023). According to the data of INTERMAGNET magnetic observatories, these earthquakes were found to be accompanied (with a delay of ~55 min) by variations in the Earth’s magnetic field in the form of a train of quasi-periodic oscillations with an amplitude of ~2–8 nT and a period of ~30 min at distances of ~210 to ~3000 km from the epicenter. It was suggested in the aforementioned study that this magnetic effect is caused by a disturbance of the geodynamo as a result of the impact of seismic waves propagating deep into Earth. This interesting hypothesis requires a detailed discussion from different points of view. A more detailed analysis of the pattern of geomagnetic field disturbance at all latitudes, performed by us, leads to a conclusion that the found quasi-periodic disturbance is a mid-latitude response to auroral electrojet variations and is not related to the earthquake. According to our estimates, variations with a source at the core–mantle interface on a time scale less than one year cannot manifest themselves on the Earth’s surface at all.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41082666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}