Izvestiya, Physics of the Solid Earth最新文献

{"title":"Pulsed Electromagnetic Sounding of a Geological Environment with Time-Varying Magnetic and Electrical Properties","authors":"P. O. Barsukov,&nbsp;E. B. Fainberg,&nbsp;E. O. Khabenskiy,&nbsp;T. A. Vasil’eva","doi":"10.1134/S1069351326700151","DOIUrl":"10.1134/S1069351326700151","url":null,"abstract":"<p>Transient responses recorded in Transient/Time-Domain Electromagnetics (TEM/TDEM) are generated and formed in the studied geological environment by several physical processes. The induction process (IN) is generated by eddy currents, which depend on the distribution of electrical conductivity in the probed volume. The superparamagnetic (SPM) effect occurs upon remagnetization of single-domain (SD) magnetite grains in the rock. The nature of polarization processes (PP) is associated with flow of electric current through a rock with frequency dependent electrical conductivity. Inductively induced polarization (IIP) is generated by eddy currents in a dispersive electrically conductive medium. The induced polarization process (IP) can be produced by displacement currents, in antenna loops with distributed capacitance and resistance. IN and IIP show at early stages of transient responses, while IN, IP and SPM appear at late stages. The relaxation rates of the processes differ: IN and IIP processes are fast while IP and SPM are slow. IN and SPM decay in phase, while IP and IIP decay in antiphase with IN. In TEM, information about the geoelectric structure of the medium is extracted from IN, while IIP, IP, and SPM usually considered noise. However, the presence or absence of polarization and magnetic effects in the recorded responses can only be identified when they dominate, dramatically distorting the shape of the IN responses. The presence of weak IIP, IP, and SPM may become apparent as late as in the process of inversion and interpretation of TEM data. Monitoring of transient responses has shown that IIP, IP, and SPM processes form in the soil layer and change over time. Variations in IIP and IP are modulated by a diurnal cycle, with early afternoon maxima and nocturnal minima. It is established that time-multiplied SPM responses in TEM magnetic antenna can be represented by a convolution of the particle volume distribution function with a narrow-band filter. SPM effects are sensitive to soil moisture and orientation of magnetizing field relative to the Earth’s magnetic field. Due to internal biological processes in the soil colloidal complex, the SPM particles contained within it clump together, forming clusters. This effect shifts the particle size distribution and, thus, the decay pattern of SPM responses. The processes of cluster formation and breakdown continuously alternate, generate anomalies in the recorded TEM signals. IP and SPM processes are typically concomitant, but the balance between of antiphase SPM–IP effects is extremely unstable over time, with polarity-flipping variations in TEM signals times greater than the inductive responses of induced polarization of the medium. This paper presents the results of three-year monitoring of the IIP, IP, and SPM effects and explores previously unknown SPM properties of soils.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":"62 2","pages":"286 - 304"},"PeriodicalIF":1.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148104199","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}

{"title":"Testing of Dynamic Correction Methods for Magnetotelluric Sounding Curves Using Model Data","authors":"S. P. Baryshnikov,&nbsp;P. Yu. Pushkarev","doi":"10.1134/S1069351326700175","DOIUrl":"10.1134/S1069351326700175","url":null,"abstract":"<p>The influence of near-surface inhomogeneities is a major challenge in magnetotelluric sounding (MTS), because it hampers retrieval of information on deep structures. Local, thin near-surface inhomogeneities cause static shifts of magnetotelluric (MT) amplitude curves while leaving the phase curves unchanged. A more complicated case arises from significant variations in the total longitudinal conductance <i>S</i> of the upper layer, which lead to changes in the shape of the amplitude curves. Variations in <i>S</i> also affect the phases of the components of the impedance tensor [<i>Z</i>] and telluric tensor [<i>T</i>], as well as the Wiese–Parkinson matrix [<i>W</i>] and magnetic tensor [<i>M</i>]. E.B. Fainberg was the first to propose a dynamic correction to MT amplitude curves, which reduces to multiplying them by a frequency-dependent factor. M.N. Berdichevsky generalized this idea to the impedance tensor and the electric distortion matrix. V.A. Kuznetsov proposed an algorithm that also accounts for magnetic distortions. These approaches are based on three-dimensional modeling of the MT field and require specifying the distribution of <i>S</i> in the upper layer and a background 1D layered model. We have implemented dynamic-correction algorithms and assessed their performance using synthetic (model) MTS data. The data were computed for a 3D model of the tectonosphere containing large-scale inhomogeneities at three structural levels: the sedimentary cover, consolidated crust, and upper mantle. Numerical experiments have shown that dynamic correction effectively suppresses the influence of sedimentary cover structures. In the different MTS data components, only the effects of deep crustal and mantle structures remained, enabling their confident localization and potentially simplifying subsequent inversion. Clearly, the success of dynamic correction depends on the accuracy with which the conductance of the upper layer and background 1D model are specified, as well as on observation errors. Future studies will evaluate the effectiveness of dynamic correction under realistic conditions.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":"62 2","pages":"189 - 199"},"PeriodicalIF":1.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148104234","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}

{"title":"Monitoring of Apparent Resistivity Variations from Audiomagnetotelluric Soundings Data at the Goryachinsk Test Site (Baikal Region)","authors":"A. K. Saraev,&nbsp;A. A. Shlykov,&nbsp;M. G. Dembelov,&nbsp;Z. M. Malkin,&nbsp;S. Agrahari","doi":"10.1134/S1069351326700308","DOIUrl":"10.1134/S1069351326700308","url":null,"abstract":"<p>The results of experimental studies on monitoring variations in apparent resistivity, as a precursor to earthquakes, based on audiomagnetotelluric soundings at the Goryachinsk test site (Baikal region) are considered. Different types of groundings of receiving electrical lines (brass, lead, chlorine–lead electrodes) have been compared. Chlorine–lead electrodes are characterized by the most stable data. In selecting stress–strain sensitive zones for the installation of monitoring equipment, the geological features of the territory were analyzed, field experimental studies were carried out to study preselected sites at fault zones, and test monitoring sessions were conducted to assess the response to tidal deformations of the Earth. The test monitoring data were used to select the frequency range for monitoring variations in apparent resistivity. The obtained apparent resistivity curves are characterized by stable behavior and small spread of values in the frequency range of 7–300 Hz. Therefore, it is advisable to perform standard magnetotelluric processing of monitoring data to obtain the apparent resistivity and impedance phase curves in the specified frequency range, and analyze variations in the magnetic and electrotelluric fields at frequencies below 7 Hz. According to the test monitoring results, it was found that tidal effects are observed in the apparent resistivity values for the E-polarized field. For the H-polarized field, there are no significant fluctuations. The values of variations with respect to the average level of 35–36 Ω m are small, 0.3–0.4 Ω m (about 1%). The results of apparent resistivity monitoring demonstrated high measurement accuracy, about 0.3%. The selected stress–strain sensitive zone can be used for long-term monitoring.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":"62 2","pages":"339 - 348"},"PeriodicalIF":1.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148104236","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}

{"title":"How the Surface Layer Affects the Results of Transient Electromagnetic Soundings","authors":"P. O. Barsukov,&nbsp;E. B. Fainberg,&nbsp;E. O. Khabenskiy,&nbsp;T. A. Vasil’eva","doi":"10.1134/S1069351326700163","DOIUrl":"10.1134/S1069351326700163","url":null,"abstract":"<p>The influence of electrical properties of the soil on the results of electromagnetic soundings using TEM (Transient Electromagnetic) method with combined receiving and exciting antennas is studied. During three summer seasons, monitoring measurements of transient responses in the microsecond range were carried out at four sites within the same geological structure composed of moraine deposits. Simultaneously , air and soil temperatures as well as capacitance of a two-wire line placed in the soil to a depth of 10 cm were measured. The diurnal cycle of variations in the capacitance of “soil capacitor” and TEM responses were recorded. During the early afternoon, capacitance reaches its maximum, while TEM responses reach their minimum. At night and in the morning, the picture is mirrored: the capacitance is minimal while the transient responses are maximum. The diurnal cycle of these parameters with 5–15% day/night variations does not depend on the amount of precipitation, but correlates well with air temperature and solar radiation. It is assumed that the detected diurnal rhythm of variations is related to biological processes in the vegetation. This hypothesis is confirmed by field and laboratory studies of plant biorhythms under changes in temperature and illumination. In each field season, there were several periods when the intensity of polarization processes anomalously increased. These processes are induced in the near-surface layers by electric potentials arising in the antenna circuit with distributed conductivity and capacitance when current pulses are transmitted through the antenna (antenna polarization effect). During these periods, the transient responses inverted the polarity at late times in early afternoon and returned to positive values at night. Trains of variation fluctuations with a diurnal period were observed for several days to several weeks.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":"62 2","pages":"305 - 321"},"PeriodicalIF":1.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148104267","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}

{"title":"Electrical Resistivity Structure of the Western Arunachal Himalayan Foreland Derived from 3D Inversion of Magnetotelluric Profile Data1","authors":"I. N. Lozovsky,&nbsp;Iv. M. Varentsov,&nbsp;D. Walia,&nbsp;S. P. Baryshnikov,&nbsp;P. V. Ivanov,&nbsp;S. G. Gokarn,&nbsp;S. S. Sanabam,&nbsp;N. K. Bori","doi":"10.1134/S1069351326700242","DOIUrl":"10.1134/S1069351326700242","url":null,"abstract":"<p>Despite its complex tectonic framework, intense seismicity, and hydrocarbon potential, the Arunachal Himalayan foreland remains poorly characterised by geophysical investigations. This study presents results from a three-dimensional inversion of magnetotelluric data acquired along a profile across its westernmost sector, resolving a pronounced layered resistivity structure. A conductive sedimentary wedge, interpreted as Siwalik molasse and Quaternary deposits, is ~0.5 km thick beneath the Brahmaputra plains and thickens northward to ~5.5 km beneath the mapped trace of the Himalayan Frontal Thrust, reaching ~6–7 km further north. Beneath it, a ~13 km thick resistive crustal layer dips northward and overlies a moderately conductive deeper zone. Constrained by passive-seismic velocity models, this resistivity framework indicates a dry, brittle upper crust above a more conductive layer whose nature requires further clarification. These results provide the first geoelectrical constraints in this segment of the foreland, offering new structural information relevant to regional seismicity and guiding future deep geophysical investigations and exploration efforts.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":"62 2","pages":"254 - 263"},"PeriodicalIF":1.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148104227","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}

{"title":"Depth Distribution of Earthquakes in the Kuril–Kamchatka Subduction Zone","authors":"I. A. Vorobieva,&nbsp;K. V. Krushelnitskii,&nbsp;E. M. Grekov,&nbsp;A. A. Skorkina,&nbsp;S. V. Baranov,&nbsp;P. A. Malyutin,&nbsp;S. D. Matochkina,&nbsp;A. P. Molokova,&nbsp;P. N. Shebalin","doi":"10.1134/S1069351326700059","DOIUrl":"10.1134/S1069351326700059","url":null,"abstract":"<p>Depth distribution is an important parameter of regional seismicity. In this paper, we examine the feasibility of using two-parameter analytical functions to approximate the distribution of earthquake depths relative to a slab in the Kuril-Kamchatka subduction zone and the distribution of absolute earthquake depths for shallow crustal events in the Okhotsk and Pacific plates. It is shown that the wealth of instrumental seismic monitoring data acquired over half a century combined with the new Earth’s structure models (SLAB 2.0) have now made it possible to describe the observed the depth distribution data analytically. Depth distributions were obtained independently for intraslab, interplate, and shallow events. According to our estimates, normal distribution relative to the slab interface is optimal for intraslab and interplates events, while the Weibull distribution proved to be the best fit for shallow events.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":"62 1","pages":"84 - 94"},"PeriodicalIF":1.0,"publicationDate":"2026-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148011910","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}

{"title":"On Geomagnetic Variations after the 2025 Myanmar Earthquake","authors":"S. A. Riabova,&nbsp;S. L. Shalimov","doi":"10.1134/S1069351326700114","DOIUrl":"10.1134/S1069351326700114","url":null,"abstract":"<p>Using ground-based low-latitude magnetometer observation stations, the intensification of geomagnetic field variations associated with a strong earthquake in Myanmar in 2025, located more than a 1000 km from the stations, was studied. The observed geomagnetic variations were interpreted as the result of propagation of three types of waves caused by the earthquake: seismic Rayleigh waves generating acoustic waves, atmospheric internal waves generated at the earthquake epicenter, and slow magnetohydrodynamic waves caused by the dissipation of acoustic-gravity waves in the lower ionosphere.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":"62 1","pages":"57 - 64"},"PeriodicalIF":1.0,"publicationDate":"2026-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148011792","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}

{"title":"Interpretation of Displacement Fields in the Krasheninnikov Volcano Caldera Obtained by Satellite Radar Interferometry Methods after the Kamchatka Earthquake of July 29, 2025","authors":"M. S. Volkova","doi":"10.1134/S1069351326700047","DOIUrl":"10.1134/S1069351326700047","url":null,"abstract":"<p>Krasheninnikov Volcano, which had shown no signs of activity for over 400 years, began erupting on August 2, 2025, with prolonged eruption of magma from the Northern Cone crater. The eruption was likely triggered by the Kamchatka megaearthquake of July 29, 2025 (<i>Mw</i> = 8.8). Using satellite radar interferometry methods based on images from the Sentinel-1 A and C satellites from two orbits, a complex deformation field was recorded in the territory of the volcano’s caldera during the period spanning the onset of the eruption. The horizontal extension component is particularly pronounced in the deformation field. The horizontal displacement of the surface to the west and east, calculated using data from two orbits, reaches 0.6 m in each direction. The vertical component of surface displacement of the volcanic edifice exceeds 0.26 m at the summit of the Southern Cone. Interpretation of the measured displacements using numerical mathematical modeling made it possible to determine the parameters of a giant vertical fracture that formed in the volcanic caldera during the intrusion of magmatic material from a deep chamber during the eruption. The fracture, 7–8 km in length, runs almost through the center of the caldera and deviates counterclockwise from the north–south direction by 12°. Based on the condition of the best agreement between theoretical and actual displacements, the fracture width is estimated at 1.5–2.2 m, the vertical extent is 2.0–2.9 km, and the depth of the upper edge is 1.25–1.5 km. The total volume of intruded material is estimated from 0.024 to 0.045 km³.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":"62 1","pages":"48 - 56"},"PeriodicalIF":1.0,"publicationDate":"2026-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148011870","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}

{"title":"Migration of Seismicity and Recent Geodynamics","authors":"V. G. Bykov,&nbsp;Yu. O. Kuzmin","doi":"10.1134/S1069351326700035","DOIUrl":"10.1134/S1069351326700035","url":null,"abstract":"<p>The migration of seismicity is one of the most striking manifestations of recent geodynamics, permeating all layers and tectonic structures of the Earth at least to a depth of 700 km, the limit where earthquakes are still detected. Each type of seismicity migration is linked to specific tectonic structures—crustal block boundaries, subduction zones, and transform faults. Viewed within a broader geodynamic context, the problem of seismicity migration contributes to a holistic understanding of the collective behavior of blocks, faults, and earthquakes, which is determined by numerous coupled processes occurring simultaneously across large spatiotemporal scales. This paper provides a review and comparative analysis of earthquake migration data from various regions reported in the literature, focusing on the main types and characteristics of migrating seismicity, proposed physical mechanisms, and current capabilities and achievements in this field of seismology.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":"62 1","pages":"1 - 25"},"PeriodicalIF":1.0,"publicationDate":"2026-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148011892","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}

{"title":"Determination of the Quality Factor of the Lithosphere of the Laptev Sea and Northern Yakutia Based on Earthquake Records at Tiksi Seismic Station","authors":"S. A. Kovachev,&nbsp;M. A. Novikov,&nbsp;A. A. Krylov,&nbsp;N. V. Libina,&nbsp;S. G. Mironyuk,&nbsp;D. D. Rukavishnikova","doi":"10.1134/S1069351326700084","DOIUrl":"10.1134/S1069351326700084","url":null,"abstract":"<p>The most seismically hazardous marine Arctic region of the Russian Federation is the Laptev Sea, located at the junction of the mid-ocean Gakkel Ridge and the continental margin of Northern Eurasia. The development of Northern Sea Route infrastructure and shelf resources necessitate assessment of the seismic hazard parameters of the Laptev Sea region, which in turn requires knowledge of the attenuation parameters of seismic waves in the regional crust. In this article, the quality factor <i>Q</i> of the crust was determined by the earthquake coda normalization method. Earthquake records were obtained at Tiksi seismic station. The dependence of the quality factor on the azimuth relative to Tiksi seismic station was found. The maximum quality factor was determined in the eastern direction, where there is practically no concentration of fault zones, in contrast to the northern, western, and southern directions, where the selected azimuths, along which the quality factor was studied, intersect the concentration of fault zones. The quality factor of the crust in these directions turned out to be almost two times lower than the quality factor values determined in the eastern direction. The value of the quality factor averaged over different directions at different frequencies is close to the quality factor parameters of other areas with active rifting, which characterizes the studied area as tectonically and seismically active. The same applies to the degree of dependence on frequency. The closest quality factor values were determined for the area of the Northern Tanzanian rifts. These quality factor estimates can be used to develop models of seismic wave attenuation in the lithosphere for earthquakes of different magnitudes and to calculate the seismic hazard of the studied area.</p>","PeriodicalId":602,"journal":{"name":"Izvestiya, Physics of the Solid Earth","volume":"62 1","pages":"95 - 111"},"PeriodicalIF":1.0,"publicationDate":"2026-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148011926","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}