Hasil untuk "Dynamic and structural geology"

A. Odzimek

<p>In October 1929, measurements of the atmospheric potential gradient (PG) began to be routinely recorded at the Magnetic Observatory in Świder, Poland. This started a new chapter in the history of the Observatory, in 1937 renamed the Geophysical Observatory in Świder. Two Benndorf electrometers recorded continuously until September 1939. War World II disrupted these observations as well as shattered efforts to publish the results of nearly a decade. Nevertheless, these early actions initiated by the Observatory management shaped its future as it became a contemporary atmospheric electricity station in the second half of the 20th century.</p>

Arkhipov, Egor A., Zotov, Sergey I., Koroleva, Yulia V. et al.

A comprehensive study of Kaliningrad soils was conducted to assess the level and structure of chemical pollution. The study demonstrates the fundamental importance of using a local background, rather than global clarkes, for reliable assessment of anthropogenic impact. The stable polycomponent pollution of soils in Kaliningrad was identified, with the formation of clearly localized geochemical anomalies. The methods of statistical analysis and geographic information mapping revealed two main sources of pollution, spatially coinciding with the zones of intensive industrial and port activity. The most significant accumulation was found for lead and zinc, the levels of which reached the levels of "severe" pollution. The application of the index system (Igeo, PI, EF, NPI, PLI, Zc) made it possible to differentiate the territory by the degree of soil pollution and identify the nature of the sources of pollutants. The results obtained prove the need for geoecological monitoring and the development of targeted environmental protection measures for identified areas of environmental pollution.

Yujiang Li, Cheng Yang, Xingping Hu et al.

On 28 March 2025, a strong MW 7.7 earthquake struck the seismic gap in the central section of the Sagaing Fault in Myanmar, causing significant damages and casualties in Myanmar and neighboring countries. Major earthquakes like this are expected to transfer stresses to nearby active regions and change their seismic hazards in the near future. In this study, based on a stratified viscoelastic model and a coseismic slip model, we calculated the co- and post-seismic Coulomb stress change (△CFS) imparted by the MW 7.7 Myanmar earthquake to the main active faults in the adjacent southwestern Yunnan region in China. Our results show that five fault segments experience up to 3 kPa of coseismic stress increase, including the Longling-Lancang Fault, the Nantinghe Fault, the Menglian Fault, the Heihe Fault, and the Red River Fault, respectively. The pattern of postseismic △CFS is similar to that of coseismic △CFS, suggesting that with the increasing elapsed time, the stress level continues to increase in these fault zones. The coseismic auxiliary stress fields show that the orientation of the principal tensile stress is predominantly NE-SW in the northern part of the southwestern Yunnan region, and shows clockwise rotation to NW-SE in the south. This stress regime controls the additional slip motion, consistent with that reflected by the coseismic shear stress change. Combined with other geophysical and geodetic data, we propose that more attention should be paid to the Longling-Lancang Fault, the Nantinghe Fault, the Menglian Fault, and the Heihe Fault, potential candidates for the next strong earthquakes in this region.

C. Collettini, A. Niemeijer, C. Viti et al.

A. Santos-Espeso, A. Santos-Espeso, M. Gonçalves Ageitos et al.

<p>Near-Term Climate Forcers (NTCFs) play a crucial role in shaping Earth's climate, yet their effects are often overshadowed by long-lived greenhouse gases (GHGs) when addressing climate variability. This study explores the climatic impact of elevated non-methane NTCF concentrations from 1950 to 2014 using CMIP6-AerChemMIP simulations. We analyse data from four Earth System Models with interactive tropospheric chemistry and aerosol schemes, leveraging a twelve-member ensemble to ensure statistical robustness. Unlike single-species or idealised radiative forcing studies, our approach captures the combined effects of co-emitted NTCF species. Our results show that the negative radiative forcing of aerosols dominates the overall NTCF impact, offsetting the warming effects of absorbing aerosols and tropospheric ozone. Multi-model mean analyses reveal three key regional climate responses: (1) a global cooling, amplified in the Arctic, where autumn temperatures decrease by up to 5 °C, (2) a 38 % increase in Labrador Sea ocean convection, and (3) changes in tropical precipitation, including a 0.6° southward displacement of the Intertropical Convergence Zone (ITCZ). This research addresses the mechanisms driving these climatic changes and underscores the importance of incorporating interactive NTCFs in climate projections. As inferred from their historical impact, future NTCF reductions could amplify regional responses to increasing GHG concentrations, thus requiring more ambitious mitigation strategies.</p>

Claire Ashcraft, Ron Harris, Julian Fretha et al.

Shear wave velocity measurements to 30 m depth (Vs30) using Multichannel Analysis of Surface Waves (MASW) indicate high seismic risk to the built environment in coastal cities adjacent to the Sunda and Banda subduction zones in Eastern Indonesia. These measurements were taken at 58 sites in the cities of Pacitan (southern Java), Lombok, Ambon, and the Banda Islands. Comparing Vs30 estimates with local geologic maps show low velocities associated mostly with unconsolidated alluvium on coastal plains where most of the built environment resides. Due to recent destructive earthquakes in two of the sites (2018 Lombok and 2019 Ambon) we were able to directly compare damage using the MMI scale to Vs30. In most cases the heavy damage was experienced in sites with low Vs30 values. The least damage was experienced near sites with high Vs30 values, which are in foothills underlain by shallow volcanic units. These data provide a way to quantify earthquake hazards in densely populated and rapidly developing regions of eastern Indonesia and provide foundational constraints for studies of resonance frequency.

Steffen Kühn

This article demonstrates that magnetic force and Newton’s law of universal gravitation can be derived from the solution of Maxwell’s equations for moving point charges. For this purpose, a plasma droplet model is postulated, consisting of an aggregation of point charges undergoing Brownian motion within a very small three-dimensional volume. As the velocity of the charges is random due to the Brownian motion, it is described by a probability distribution. It is shown that a non-zero velocity standard deviation leads to the magnetic force, while Newton’s law of universal gravitation can be derived from a non-zero velocity variance. This suggests that magnetism and gravitation might be closely related.

A. Lalomov

Jude Zeitouny, Wolfgang Lieske, Arash Alimardani Lavasan et al.

Microbially induced calcite precipitation (MICP) is a green bio-inspired soil solidification technique that depends on the ability of urease-producing bacteria to form calcium carbonate that bonds soil grains and, consequently, improves soil mechanical properties. Meanwhile, different treatment methods have been adopted to tackle the key challenges in achieving effective MICP treatment. This paper proposes the combined method as a new MICP treatment approach, aiming to develop the efficiency of MICP treatment methods and simulate naturally cemented soil. This method combines the premixing, percolation, and submerging MICP methods. The strength outcomes of Portland-cemented and MICP-cemented sand using the percolation and combined methods were compared. For Portland-cemented sand, the UCS values varied from 0.6 MPa to 17.2 MPa, corresponding to cementation levels ranging from 5% to 30%. For MICP-cemented sand, the percolation method yielded UCS values ranging from 0.5 to 0.9 MPa, while the combined method achieved 3.7 MPa. The strength obtained by the combined method is around 3.7 times higher than that of the percolation method. The stiffness of bio-cemented samples varied between 20 and 470 MPa, while for Portland-cemented sand, it ranged from 130 to 1200 MPa. In terms of calcium carbonate distribution, the percolation method exhibited higher concentration at the top of the sample, while the combined method exhibited more precipitation at the top and perimeter, with less concentration in the central bottom region, equivalent to 10% of a half section’s area.

Juan Manuel Montes

This work is an attempt to modernise Weber’s electrodynamics to make it compatible with the high-velocity regime, and with the existence of a limiting velocity, <i>c</i>. For this purpose, starting from the law of energy conservation and the mass–energy equivalence, new expressions for potential energy and for kinetic energy are derived jointly which are consistent with an ultimate velocity of the value of <i>c</i>. The new potential energy, already reported by Phipps, becomes Weber’s expression in the limit of low velocities. The new kinetic energy differs from the relativistic expression, but, like the latter, it also becomes the Newtonian expression in the limit of low velocities. New expressions for force and linear momentum are also derived which complete a new mechanics. Phipps’ potential energy and new kinetic energy are applied to the problem of two interacting charges in a radial motion and orbital motion. The new framework is also applied to the problem of a charge moving between the two plates of a charged capacitor, obtaining a result similar to that obtained by means of Maxwell–Lorentz electromagnetism and relativistic mechanics. The metaphysical considerations that clearly differentiate the conventional framework from the new framework proposed here are discussed.

M. Hossain, S. Ao, T. Mondal et al.

The tectonic deformation of the outer Indo-Burman Ranges (i.e., Chittagong Tripura Fold Belt, CTFB) is associated with the oblique convergence of Indo-Burmese plates since the latest Miocene. This article presents detailed field evidence of deformation structures and their kinematics in the exposed Tertiary successions in the CTFB. We combine observations made in this study with the published structural, geodetic, and seismic data sets to present an overview of the active tectonic framework of the region and its strain partitioning. To determine the kinematic evolution, décollement depth, and amount of strain, we combined geologic field mapping, structural analysis of fifteen anticlines, fracture/lineament analysis, and paleostress analysis of faults that define the ∼100 km wide CTFB. Structural data and kinematic analyses suggest subhorizontal plane strain with approximately 10% east-west shortening (oriented ~65°) that is perpendicular to the axial plane (oriented ~155°) of the CTFB anticlines. No evidence of significant transpression or strike-slip faulting has been observed in the CTFB and, therefore, suggests that full slip-partitioning is normal to the outer belt and parallel to the inner belt of the IBR. Paleostress analysis results are in good agreement with the present-day stress regime, and this implies that past and present deformation is dynamically related with the normal component of India-Burma oblique vector velocity motion.

E. S. Gorbatov, A. Korzhenkov, S. Kolesnikov et al.

—Structural and lithological comparison of intraformational plicative liquefaction deformations (convolutions) in Late Quaternary lacustrine complexes of the Baltic Shield (sediments of small glacial lakes) and the Tien Shan (sediments of a large stationary basin in the Issyk-Kul depression) is carried out in order to clarify their genesis. These regions have sharply different levels of seismotectonic activity, which makes it possible to most fully determine the role of a seismic factor in the formation of bedding disturbances. Convolutions in the Baltic Shield are represented by load casts, flame structures, pseudonodules, and regular folds with more pronounced anticlinal bends. It is shown that convolutions occur here only in the most liquefied soils (siltstones and fine-grained sands) with low cohesion and fluid permeability in the case of unstable (increased density and coarsening of the sediment from bottom to top) or neutral (homogeneous composition) stratification of weakly consolidated sediments, and the ratio of the widths of the synclinal and anticlinal parts of the folds (Ksyn) for these structures is 1.0–7.5. These signs point to the formation of disturbances because of a spontaneous instability or an instability initiated by weak mechanical influences in the sedimentary stratum under conditions of a normal vertical gradient of the sediment viscosity. Deformations in the second region are structures typical of the Baltic Shield, columnar structures of deep interpenetration of layers, diapirs, and clastic dikes. There are also flexural folds with Ksyn ≈ 1, which formed at a higher degree of sediment consolidation than the actual liquefaction structures. The convolutions of the Issyk-Kul depression are developed not only in sand–silty sediments but also in relatively lowly liquefied soils (clay, gravel, and pebbles). These structures formed under both unstable and stable density stratification of the sediment (for example, clay-on-sand), and Ksyn = 0.3–2.5. Thus, the formation of convolute structures in the Issyk-Kul depression is impossible without strong dynamic impacts on stratified sediments during their accumulation. The results obtained make it possible to substantiate the predominantly diagenetic (convective and landslide) genesis of convolutions in the lacustrine complexes of the Baltic Shield and the seismogenic genesis in the limnogenic deposits of the Tien Shan. A number of new criteria for identifying seismites are proposed, which determines the practical significance of the study.

P. V, Roopa M

Abstract: A tremor or a movement of the ground occurs during an earthquake on Earth's surface. Earthquakes can also cause landslides and volcanic eruptions. Natural disasters or human activity can produce earthquakes, which are defined as seismic events generating seismic waves. Earthquakes most commonly occur when geological faults rupture, however they can also occur as a result of volcanic eruptions, landslides, mine explosions, and nuclear testing. The study of structural behavior towards different ground motions is therefore one of the main criteria to determine damage intensity. Structural Analysis of a residential building is carried out by using ETabs Software. Present study is intended to study the dynamic behavior of Multistorey Reinforced Concrete structure by considering, an existing G+13 storey residential building is modeled and its structural behaviour is studied using Time history method by considering different high intensity earthquakes. The behaviour of the building is studied mainly for its base shear, Storey displacement and maximum joint displacement.

Long-Chuan Wu, R. Thorsen, S. Ottesen et al.

An understanding of fault seal is crucial for assessing the storage capacity and containment risks of CO2 storage sites, as it can significantly affect the projects on across-fault and along-fault migration/leakage risk, as well as reservoir pressure predictions. We present a study from the Smeaheia area in the northern Horda Platform offshore Norway, focusing on two fault-bounded structural closures, namely the Alpha and Beta structures. We aim to use this study to improve the geological understanding of the northern Horda Platform for CO2 storage scale-up potentials and illustrate the importance of fault seal analysis in containment risk assessment and storage capacity evaluation of a CO2 storage project. Our containment risk assessment shows that the Alpha structure has low fault-related containment risks; thus, it has a potential value to be an additional storage target. The Beta structure shows larger fault-related containment risks due to juxtaposition of the prospective storage aquifer with the basement across the Øygarden Fault System. The storage capacity of Smeaheia will be determined by the long-term dynamic interplay between pressure depletion and recharging. Our study shows that across-fault pressure communication between Smeaheia and the depleting Troll reservoir is likely to be through several relay ramps of the Vette Fault System. However, Smeaheia also shows pressure-recharging potentials, such as through the subcropping areas at the Base Nordland Unconformity. The depletion observed in the newly drilled well 32/4-3S gives a good validation point for our fault seal predictions and provides valuable insights for future dynamic simulations. Thematic collection: This article is part of the Geoscience for CO2 storage collection available at: https://www.lyellcollection.org/cc/geoscience-for-co2-storage

T. Ulrich, A. Gabriel, E. Madden

B. Claussmann, J. Bailleul, F. Chanier et al.

1. Abstract Along active margins, the combination of predominant tectonic activity and shallow-marine mixed siliciclastic-carbonate source systems developing upon and around actively growing structures challenges traditional source-to-sink models. This study aims to investigate the implications of mixed siliciclastic-carbonate shelfal domains located in contrasting geotectonic settings (thrust forelimb and backlimb) for the development of the concomitant gravity-driven systems beyond the shelf edges. Here, we document the vertical and lateral stratigraphic variabilities of the shelf-derived turbidites and mass-transport deposits (MTDs) at outcrop-scale through the integrated interpretation of photogrammetry, field and taphonomic data from the emerged southern portion of the Hikurangi subduction margin. Results highlight the role and importance of varying structural setting of the sediment source, whereby the different morphologies of the source regions (continent-attached forelimb, continent-detached backlimb) control the development of highly varied shelf-derived gravity-driven depositional systems that interact with the structures across the same confined intra-slope basin. The deposits are tens to a few hundred of meters in thickness and have a lateral extent of several kilometers. The depositional systems are characterized by durations of 1–2 Ma and were primarily controlled by the geometries and tectonic motion of the underlying structures at the shelf edges. Shelf-derived mass-wasting systems occurred on both sides of the actively growing thrust structures and were sourced from both shelfal domains that were attached or detached from the continental domain. When sourced from the backlimbs however, the subsequent MTDs exhibit more complex internal architectures, ultimately recording the dynamic changes in slope gradient, and can therefore be used as proxies for unraveling the tectonic activity of an individual structure. Our study provides new insights to better predict mixed siliciclastic-carbonate depositional settings along active margins, sourced from thrust forelimb and backlimb. These results may be important for deep-marine exploration and tectonostratigraphic reconstruction of fold-and-thrust belts.

M. Häusler, Paul R. Geimer, R. Finnegan et al.

Abstract. Natural rock arches are rare and beautiful geologic landforms with important cultural value. As such, their management requires periodic assessment of structural integrity to understand environmental and anthropogenic influences on arch stability. Measurements of passive seismic vibrations represent a rapid and non-invasive technique to describe the dynamic properties of natural arches, including resonant frequencies, modal damping ratios, and mode shapes, which can be monitored over time for structural health assessment. However, commonly applied spectral analysis tools are often limited in their ability to resolve characteristics of closely spaced or complex higher-order modes. Therefore, we investigate two techniques well-established in the field of civil engineering through application to a set of natural arches previously characterized using polarization analysis and spectral peak-picking techniques. Results from enhanced frequency domain decomposition and parametric covariance-driven stochastic subspace identification modal analyses showed generally good agreement with spectral peak-picking and frequency-dependent polarization analyses. However, we show that these advanced techniques offer the capability to resolve closely spaced modes including their corresponding modal damping ratios. In addition, due to preservation of phase information, enhanced frequency domain decomposition allows for direct and convenient three-dimensional visualization of mode shapes. These techniques provide detailed characterization of dynamic parameters, which can be monitored to detect structural changes indicating damage and failure, and in addition have the potential to improve numerical models used for arch stability assessment. Results of our study encourage broad adoption and application of these advanced modal analysis techniques for dynamic analysis of a wide range of geological features.

J. Skinner, C. Fortezzo, P. Mouginis-Mark

Abstract We document a set of channels in a section of the Martian cratered highlands located between crustal massifs northeast of Hellas Planitia that are visible in cross section and planview >200 m below the surface. The morphometry and spatial distribution of the outcrops provide concrete geological evidence of a dynamic aqueous system in a structural sub-basin during the Early to Middle Noachian, bolstering evidence of conditions compatible with sustained liquid water on the surface very early in Mars' history.

Ilia P. Dudchenko, Dmitry V. Kostylev, Sergey A. Gulyakov et al.

This article describes the process and results of the development and testing of a cost-effective, portable, safe to move by air geophysical pulse voltage generator for seismic exploration of the subsurface. The generator is based on high-speed power electronic keys of a new generation consisting of an insulated gate bipolar transistor or a field-effect transistor based on silicon carbide, a compact power converter of alternating voltage from an autonomous generator or electric network to direct voltage using pulse-width modulation and current or voltage stabilization depending on the mode set by a researcher. Field tests were conducted to confirm the suitability of the developed design of the generator and the correctness of the chosen parameters of its elements. To this end, a detailed analysis of the effect of the developed geophysical generator on the parameters of the geoenvironment was carried out.

Л.А. Сим, П.А. Каменев , Л.М. Богомолов

Для верификации представлений о неотектонических и современных напряжениях Сахалина анализируются структурно-геоморфологические признаки напряженного состояния этого региона, обнаруженные в ходе полевых работ 2019–2020 гг. Наряду с новыми полевыми замерами структурно-геоморфологическим методом представлены данные о деформации земной коры на основе GPS/ГЛОНАСС-измерений. Приводятся данные геофизических исследований (сейсмологических и скважинных методов). Подтверждено выделение трех типов областей с различной геодинамической обстановкой растяжения, сжатия и чистого сдвига. Отмечены вариации современного поля напряжений на границах областей с различной геодинамической обстановкой формирования новейших разломов. Северный Сахалин имеет специфические направления осей сжатия неотектонических напряжений, выраженные в северо-восточных ориентировках, в отличие от преобладающих субширотных ориентировок на всем острове. Проведенные исследования показали, что на юге Сахалина граница между Амурской и Охотской микроплитами проходит, скорее, по Западно-Сахалинскому, а не по Центрально-Сахалинскому разлому.