Earth's Interior Research Articles

ОБРАБОТКА РЕЗУЛЬТАТОВ GPS-МОНИТОРИНГА ПРИ ИНТЕНСИВНЫХ ДВИЖЕНИЯХ ЗЕМНОЙ КОРЫ В СЕЙСМОАКТИВНЫХ РЕГИОНАХ КАЗАХСТАНА

The article presents the results of GPS-monitoring studies in the zone of major tectonic faults on the territory of Almaty. It has been established that monitoring the movement of the Earth's crust is necessary to understand the processes preceding earthquakes and to develop forecasting models. Knowledge of the movement of the Earth's crust is important to ensure the safety of infrastructure such as roads, bridges and residential buildings. The results of the study can be useful for conducting scientific research (when monitoring, analyzing and predicting the movement of the Earth's crust in regions with increased seismic activity) related to the structure of the Earth's crust and the tectonics of the region.

ГЕОДИНАМІЧНИЙ СТАН ЗАКАРПАТСЬКОГО ВНУТРІШНЬОГО ПРОГИНУ ЗА РЕЗУЛЬТАТАМИ ДЕФОРМОМЕТРИЧНИХ СПОСТЕРЕЖЕНЬ У РЕГІОНІ

Background. The relevance of the research is determined by the gradual increase in local seismicity in the region, which occupies a peculiar geographical location, through which oil, gas and product pipelines pass, and in which critical infrastructure facilities are located that may be affected by the underground natural disaster. It is important to have information on the movements of the upper layers of the Earth's crust, their kinematics and dynamics, which significantly affect the stress-strain state of rocks and the release of energy from geomechanic processes. It is also necessary to investigate the influence of the region's geodynamics on the discharge of the stress-strain state of rocks. Methods. The research methodology is to construct time-dependent crustal displacements and compare velocities and accelerations of crustal movements in the intervals of anomalous modern lateral movements of the Earth's crust. The velocities and accelerations of crustal movements are calculated, the kinematics of movements and seismicity of the region are compared. Correlation analysis of the observed series is applied. To solve the tasks, we used the results of observations of horizontal crustal movements in the Oașh deep-seated fault area using a quartz strain gauge with a base of 24.5 m mounted in the adit of the Korolevo urban-type settlement. The seismic data were obtained using digital seismometers operating at the monitoring geophysical station of the Seismicity Department of the Carpathian region of S.I. Subbotin Institute of Geophysics of the National Academy of Sciences of Ukraine. Results. The article discusses the geodynamics of the Transcarpathian Inner Trough based on observations of modern lateral movements of the Earth's crust in the Oașh deep-seated fault area, which in 2021 were represented by rock extensions of +12.61x10-7. The physical parameters of geomotion in the region were calculated, the spatiotemporal distribution of local seismicity was established, and the relationship between seismic and geodynamic states in Transcarpathia in 2021 was studied. The variations of displacements of the upper layers of the Earth's crust over the entire period of deformation monitoring observations in Korolevo urban-type settlement (1999–2021) and the temporal distribution of local underground shocks were studied. Conclusions. The analysis of the spatio-temporal distribution of local seismicity and modern lateral movements of the Earth's crust over the entire period of deformation monitoring observations in the Oașh deep-seated fault area has indicated an increase in the seismicity of the region in the intervals of intense crustal movements and the presence of periods of crustal movement fluctuations for 12 years: familiar variable processes (expansion and contraction of rocks, the total magnitude of displacement fluctuations in the region of zero movements) were detected for 2–3 years. The most relevant and important are the periods of 9–10 years following these calm intervals, since during this time earthquakes are recorded and their frequency is also found to be increasing. The intensification of seismicity in the region is observed against the background of general rock extension, which occurs due to the steady age-related crustal movements. At the present stage, the current crustal movements are in a state of rock expansion, and if this trend does not change, an increase in seismicity in the region should be expected.

ГЕОХИМИЧЕСКИЕ ОСОБЕННОСТИ ГАББРОИДОВ И ГРАНИТОИДОВ НЯТЫГРАНСКОГО КОМПЛЕКСА (БУРЕИНСКИЙ МАССИВ)

Gneissic gabbros, gabbrodiorites, granodiorites, and granites of the Late Proterozoic Nyatygransky Complex, exposed by erosion in the eastern part of the Bureya massif, form small intrusive bodies within the boundaries of the Melgin metalliferous trough, as well as around it. Analysis of chemical and trace-element compositions of rocks from the Nyatygransky Complex revealed their geochemical features. The calculated agpaitic index values for gabbroids are very low and range from 0.11 to 0.33. Granodiorites have slightly higher index values ranging from 0.5 to 0.38, and only gneiss-granites are plumasitic with agpaitic index values between 0.45 and 0.75. Both gabbroids and granitoids are assigned to calc-alkaline rocks by their agpaitic index. Gneissic gabbros, dominated by dark-colored minerals (labradorite, hornblende), show enhanced alkalinity not common to gabbros (4%); in them, the magnesium content prevails over the iron content. They are characterized by high alumina content (15–18%), reaching 20.38%. Geochemically, they are interpreted as I-type igneous rocks. Gneissic granitoids with a slight predominance of the iron content over the magnesium content are less aluminous (Al2O3 12–15%). They are interpreted as S-type (sedimentary) and I-type (igneous) granitoids, formed in sedimentary and granitic layers of the earth’s crust. According to petrochemical diagrams, the gabbroids and granitoids of the Nyatigransky Complex belong to the volcanic arcs of the active continental margin.

Organization of continuous monitoring of quarry sides

The article discusses the fundamental conceptual positions underlying the study of the significant impact of humanity on the lithosphere, which is approaching and may exceed its limits. It is noted that most surface layers of the Earth's crust are non-renewable, and the majority of chemical elements have found practical applications, yet only about oneseventh of the extracted minerals are used in the production of final products. One of the main challenges in developing open-pit mines is maintaining the stability of the pit walls. As the depth of the pit increases, this issue becomes increasingly critical. The article emphasizes the importance of enhanced study of the fundamentals of managing rock masses in mining operations and the practical application of this knowledge, as it significantly contributes to solving problems and examples related to assessing the stability of slope walls and pit benches.

Gravimetric inversion based on model exploration with growing source bodies (Growth) in diverse earth science disciplines

<abstract> <p>Gravimetry is a discipline of geophysics that deals with observation and interpretation of the earth gravity field. The acquired gravity data serve the study of the earth interior, be it the deep or the near surface one, by means of the inferred subsurface structural density distribution. The subsurface density structure is resolved by solving the gravimetric inverse problem. Diverse methods and approaches exist for solving this non-unique and ill-posed inverse problem. Here, we focused on those methods that do not pre-constrain the number or geometries of the density sources. We reviewed the historical development and the basic principles of the Growth inversion methodology, which belong to the methods based on the growth of the model density structure throughout an iterative exploration process. The process was based on testing and filling the cells of a subsurface domain partition with density contrasts through an iterative mixed weighted adjustment procedure. The procedure iteratively minimized the data misfit residuals jointly with minimizing the total anomalous mass of the model, which facilitated obtaining compact meaningful source bodies of the solution. The applicability of the Growth inversion approach in structural geophysical studies, in geodynamic studies, and in near surface gravimetric studies was reviewed and illustrated. This work also presented the first application of the Growth inversion tool to near surface microgravimetric data with the goal of seeking very shallow cavities in archeological prospection and environmental geophysics.</p> </abstract>

Characterization and Modeling of Reinforced Earth Structures

Characterization and Modeling of Reinforced Earth Structures

Characterization of anisotropy in basin-scale subsurface using teleseismic receiver function analysis

Teleseismic receiver function (RF) analysis offers a passive-source analogue to detect impedance boundaries using the converted body waves generated by earthquakes. While the technique traditionally has targeted deep earth structures such as the Moho and transition zones, there is growing interest in assessing its applicability in basin-scale seismic characterization, ultimately aimed for onshore commercial integration as a cost-effective complement to existing active-source seismic surveys. Specifically, the conventional broadband seismometers used in global observational seismic experiments are not only logistically simple in terms of data acquisition, but they also record ground motions in three mutually orthogonal time series, enabling effective detection of shear waves and directional variations of observed signals. Here, we perform teleseismic RF analysis to detect shear-wave anisotropy and related symmetry axes orientations in a basin setting, using open-source seismic data recorded at 55 closely spaced seismic stations in the LaBarge Passive Seismic Experiment deployed in Wyoming between November 2008 and June 2009. We find that the strengths and geometry of the observed anisotropy are variable along the array. Significantly, not only can anisotropy effectively delineate subsurface fault interfaces, it can also substantiate and reveal additional interpretable signals that are otherwise disregarded. The estimated fast axes orientations compare favorably with the complex fracture systems documented in the region. Finally, we show that P-to-S amplitude variations with P incidence are systematic and modelable using existing computational tools, offering an opportunity to develop an analysis technique similar to amplitude variation with offset with the products of RF analysis.

The influence of stress-induced anisotropy in undrained yield and ultimate shear strengths in brittle loose deposited silts

The typical undrained behaviour observed in brittle non-plastic soil is ruled by the combination of density and stress levels. Some specific silty and sandy mining waste with particles morphologies that generate high smallstrain stiffness to strength ratios when increasing deviatoric stress (q) in stress paths that tend to decrease mean effective stress (p´) may drop down the deviatoric stress before reaching the frictional critical sate. The ratio between the peak (or yield) value (Su=q/2) and the corresponding p´ is usually associated with a locus in q-p´ that is commonly associated to a straight Instability Line (IL) with a unique ratio (ηL) and for an initial state parameter. However, this is not the case if an induced anisotropy is installed differently while the at rest stress ratio (hereby defined as initial, K0) is achieved by continuous rate the principal stresses consolidated in lab prior to loading with distinct values. This fabric effect is decisive for design and in stability assessment of earth structures, like dams or piles of mine tailings where non-plastic fines are dominant, even if the prevailing stress-path is in compression. In a thorough and quite complete program varying these conditions on iron ore tailings from Minas Gerais state in Brazil, reconstituted in lab with differentiated state parameters, and its relation to the induced anisotropy effect.

In situ ageing of a lime/cement-treated expansive clayey soil

This paper focuses on the performances of a treated expansive clayey soil sampled on an embankment constructed in 2010. Two types of treatment used during construction are considered: 4% lime as well as a mix of 2% lime and 3% cement. Oedometer tests were carried out on different parts of the embankment, to assess the compressibility of the soil. The results were compared to the compression curve of the untreated soil, also sampled in the same embankment. Several complementary aspects were also investigated (moisture content, dry density,…) to assess the ageing process of the embankment. The obtained results showed that the behaviour of the material from the outer part of the backfill is similar to the mechanical performances of the untreated soil, demonstrating a strong alteration of the effect of both treatments. This alteration is noticeable until a horizontal distance of about two meters from the surface. Beyond this distance, the performance of the soil is comparable to the mechanical behaviour of treated soil. These observations, similar for each treatment dosage, tend to question the durability of the treatment at the edge of the earth structure.

The relative contribution of mantle and continental crustal sources to primitive arc magmas: Insights from the early Palaeozoic Famatinian - Puna arc

Subduction zone magmatism plays a crucial role in driving the exchange of chemical elements between Earth's interior and surface. This survey focuses on the compositional analysis of primitive mafic rocks within an ancient Early Palaeozoic subduction-related magmatic belt. The primary objective is to assess the petrological processes involved in the cycling of chemical elements from the Earth's surface, through the slab and mantle reservoirs, to the crustal arc magmatic systems. By examining the composition of primitive mafic rocks and utilizing inverse modelling techniques, we estimate the composition of the ambient mantle source, which appears to have undergone depletion due to melt extraction before being metasomatized by slab agents. The inverse approach reveals that fluid-mobile elements (Th, U, La, Ce, and Sr) were primarily derived from the slab contribution and suggests that subduction had influenced the abundances of Nb and Ta in the modified mantle source. Conversely, Zr, Hf, and Ti were sourced from the ambient mantle. However, the available mineral/melt partition coefficients used in inverse modelling may overestimate the contribution of Sr and Nb from the slab. Instead, forward modelling is limited by the incomplete preservation of ancient volcanic arc geology. The forward mixing models that consider the interaction between slab-released sedimentary-derived melts and the ambient depleted mantle can explain the observed variations in Nd and Sr isotopic ratios in primitive mafic rocks. Two-component mixing shows that a small mass fraction (≤1.5 wt%) of average Cambrian continental sediments subducted beneath the Early Ordovician arc into a MORB-depleted mantle source account for the abundance of sedimentary-supplied elements such as Th, La, and Ba, as well as radiogenic isotope ratios of 143Nd/144N and 87Sr/86Sr in the primitive mafic magmas. The chemical and isotopic composition of deep-seated primitive mafic rocks reveals a decoupling between incompatible trace elements, which display minimal variation, and radiogenic isotopic ratios, which exhibit a wide range and reflect contributions from continental crustal reservoirs. To explain the observed variations in trace elements and isotopes, we propose a simple model involving simultaneous bulk assimilation (A) and imperfect fractional crystallization (IFC) in an open igneous system, where crystal accumulation and assimilation occur concurrently. Especially, deep crustal physicochemical interaction of primitive arc magmas with supracrustal host rocks may mask the expected clear signature of subarc mantle petrological processes. Our assessment of the Famatinian-Puna arc, an ancient subduction zone, concurs with estimates from active volcanic arcs, underscoring the general applicability of this study case to subduction zone magmatism.

Structural and tectonic features of the Transcarpathian trough according to gravity and magnetic data

Based on the analysis and interpretation of gravity and magnetic field anomalies, we studiedthe peculiarities of fault tectonics, structural-tectonic structure (including salt dome tectonics) of the Transcarpathian trough. We identified signs of the manifestation of deep faults and other large structural-tectonic elements in anomalies of gravity and magnetic fields. We then traced these structural-tectonic units by comparing the morphology, intensity, dimensions, and directions of the typical anomalous zones in the gravitational and magnetic fields with the tectonic structure of the region.
 We used digital maps of gravitational and magnetic fields; averaging transforms and relief-shadow images, we mapped local gravimagnetic anomalies. Analysis of the spatial structure of the original gravimagnetic fields and their transforms and structural-tectonic maps yielded a reflection of large tectonic elements of fault tectonics, anticlinal and salt dome structures in the gravimagnetic fields. Based on gravimagnetic data, the tectonic structure of the Transcarpathian trough was clarified, and the boundaries of tectonic zones and microplates were traced. The zone of the Transcarpathian deep fault is identified as a tectonic zone traced by a band of intense local positive anomalies of the gravity field along the Flysch Carpathians to the border of the Marmarosh massif. It is limited by high gradients from the southwest and northeast and is a reflection of the Pieniny and Marmarosh rock zones. The zone of the Transcarpathian deep fault is considered a suture zone of the Inner and Flysch Carpathians. In the structure of the anomalous gravity field of the Transcarpathian trough, a number of local anomalies associated with salt stocks, as well as individual anomalies, expected to be connected to salt-bearing deposits, werefound.
 We confirmed the effectiveness of gravimagnetic methods in the geological conditions of the Transcarpathian trough to detect anticlinal structures, basement protrusions, which create favorable conditions for oil and gas traps in sedimentary strata. Interpreting anomalous gravimagnetic fields in combination with geological and tectonic materials is an important condition for the integral process of studying the geological and tectonic structure of the Earth’s crust in the Transcarpathian region.

A Three‐Field Formulation for Two‐Phase Flow in Geodynamic Modeling: Toward the Zero‐Porosity Limit

AbstractTwo‐phase flow, a system where Stokes flow and Darcy flow are coupled, is of great importance in the Earth's interior, such as in subduction zones, mid‐ocean ridges, and hotspots. However, it remains challenging to solve the two‐phase equations accurately in the zero‐porosity limit, for example, when melt is fully frozen below solidus temperature. Here we propose a new three‐field formulation of the two‐phase system, with solid velocity (vs), total pressure (Pt), and fluid pressure (Pf) as unknowns, and present a robust finite‐element implementation, which can be used to solve problems in which domains of both zero porosity and non‐zero porosity are present. The reformulated equations include regularization to avoid singularities and exactly recover to the standard single‐phase incompressible Stokes problem at zero porosity. We verify the correctness of our implementation using the method of manufactured solutions and analytic solutions and demonstrate that we can obtain the expected convergence rates in both space and time. Example experiments, such as self‐compaction, falling block, and mid‐ocean ridge spreading show that this formulation can robustly resolve zero‐ and non‐zero‐porosity domains simultaneously, and can be used for a large range of applications in various geodynamic settings.

TO THE 60TH ANNIVERSARY OF THE DEPARTMENT OF EARTH SCIENCES OF THE NATIONAL ACADEMY OF SCIENCES OF UKRAINE. Part 1. Historical outline of the development of natural sciences from the founding of the Academy of Sciences of Ukraine to the establishment of the Department of Earth and Space Sciences of the Academy of Sciences of the Ukrainian SSR (1918–1962)

The history of the formation and development of Earth sciences since the founding of the Ukrainian Academy of Sciences (UAS) contains a significant amount of factual material. Taking into account the limitation of the volume of the journal publication, the authors divided the chronological review of the history of natural sciences in the system of the Academy dedicated to the 60th anniversary of the Department of Earth Sciences of the National Academy of Sciences of Ukraine into three parts. In the first part, the main historical events in dates, facts and personalities of the formation and development of the natural sciences of Ukraine from the founding of the Ukrainian Academy of Sciences in 1918 to the organizational and structural formation of the Department of Earth and Space Sciences of the Academy of Sciences of the Ukrainian SSR in 1963 are listed in chronological order. In the second and third parts, the formation and development of scientific institutions of the Department of Earth Sciences are considered in accordance with (1963–1990) and after (1991–2023), i.e., the acquisition of independence by Ukraine, as well as brief information about the achievements of the members of the Academy. Scientists-naturalists from the moment of establishment of UAS and during its first 45 years passed all stages of its formation and development. Among the outstanding achievements, which became a unique contribution to the development of natural sciences during this period, the following should be included: (a) the substantiation of a new theoretical direction in geological science – tectoorogeny, the doctrine of the Earth's tectonosphere, (b) the beginning of the creation of the concept of the abiogenic (inorganic) origin of oil and gas at extremely high temperatures and pressures in the Earth's upper mantle, (c) studying the deep structure of the Earth’s crust and the upper mantle of the territory of Ukraine by geophysical methods. The above list of key achievements includes only breakthrough ideas and theories. In the text of the article, the content and significance of the main achievements of natural scientists of the Academy are considered in the given biographical references about their authors.

Robust estimates of the ratio between S- and P-wave velocity anomalies in the Earth's mantle using normal modes

Seismic tomography allows us to image the interior of the Earth. In general, to determine the nature of seismic anomalies, constraints on more than one seismic parameter are required. For example, the ratio R between perturbations in vs and vp (dlnvs and dlnvp, respectively) is studied extensively in the lowermost mantle and interpreted in terms of thermal and/or chemical anomalies. However, to jointly interpret tomographic models of variations in vs and vp or their ratio R, it is essential for them to share the same local resolution. Most existing models do not provide resolution information, and thus cannot guarantee to honour this condition. In addition, uncertainties are typically not provided, making it difficult to robustly interpret the ratio R=dlnvs/dlnvp. To overcome these issues, we utilise the recently developed SOLA tomographic method, a variant of the linear Backus–Gilbert inversion scheme. SOLA retrieves local-average model estimates, together with information on their uncertainties, whilst it also provides direct control on model resolution through target kernels. In this contribution, we apply SOLA to normal-mode data with sensitivity to both vs and vp, as well as density throughout the mantle. Specifically, we aim to develop models of both vs and vp with the same local resolution. We test our methodology and approach using synthetic tests for various noise cases (random noise, data noise or also additional 3D Earth noise due to variations in other physical parameters than the one of interest). We find that the addition of the 3D noise increases the uncertainties in our model estimates significantly, only allowing us to find model estimates in six or four layers for vs and vp, respectively. While the synthetic tests indicate that no satisfactory density models can be obtained, we easily manage to construct models of dlnvs and dlnvp with almost identical resolution, from which the ratio R can be robustly inferred. The obtained values of R in our synthetic experiments significantly depend on the noise case considered and the method used to calculate it, with the addition of 3D noise always leading to an overestimate of R. When applying our approach to real data, we obtain values of R in the range of 2.5–4.0 in the lowest 600 km of the mantle, which are consistent with previous studies. Our model estimates with related resolving kernels and uncertainties can be used to test geodynamic model predictions to provide further insights into the temperature and composition of the mantle.

Utilizing Machine Learning to Examine the Spatiotemporal Changes in Africa’s Partial Atmospheric Layer Thickness

As a crucial aspect of the climate system, changes in Africa’s atmospheric layer thickness, i.e., the vertical distance spanning a specific layer of the Earth’s atmosphere, could impact its weather, air quality, and ecosystem. This study did not only examine the trends but also applied a deep autoencoder artificial neural network to detect years with significant anomalies in the thickness of Africa’s atmosphere over a given homogeneous region (derived with the rotated principal component analysis) and examine the fingerprint of global warming on the thickness changes. The broader implication of this study is to further categorize regions in Africa that have experienced significant changes in their climate system. The study reveals an upward trend in thickness between 1000 and 850 hPa across substantial parts of Africa since 1950. Notably, the spatial breadth of this rise peaks during the boreal summer. Correlation analysis, further supported by the deep autoencoder neural network, suggests the fingerprint of global warming signals on the increasing vertical extent of Africa’s atmosphere and is more pronounced (since the 2000s) in the south-central regions of Africa (specifically the Congo Basin). Additionally, the thickness over the Sahel and Sahara Desert sees no significant increase during the austral summer, resulting from the counteracting effect of the positive North Atlantic Oscillation, which prompts colder conditions over the northern parts of Africa. As the atmospheric layer thickness impacts the temperature and moisture distribution of the layer, our study contributes to its historical assessment for a sustainable ecosystem.

Parmenides’ Structure of the Earth

It is generally accepted that the enigmatic fragment 12 of Parmenides, supplemented by the first part of A.tius II 7.1, represents an unlikely cosmos which comprises alternating spherical crowns of fire and night, surrounding the earth. A comparison of the fragment and A.tius’ text shows that the latter adds nothing substantial to the fragment. Thus, fragment 12 can actually represent the structure of the earth, which consists of a core of fire, is surrounded by the layers of the earth’s crust, into which heat is transmitted from within, and on which the goddess of life dwells.

Representation of three-dimensional mass distribution of the Earth's interior by biorthogonal series and its use for studying internal structure of the planet

This paper utilizes the mathematical concept of approximation within an ellipsoid from a single viewpoint to present the spatial mass distribution function of the Earth's interior and its internal potential. The primary focus lies in constructing the volume distribution of masses in the planet's interior, with the expansion coefficients being linear combinations of the Stokes constants. Several possible approaches are suggested for determining accurately these coefficients employing three-dimensional (biorthogonal) polynomials. By expressing the mass distribution function of the Earth's interior and its internal potential as a series, an algorithm is introduced for the calculation of gravitational energy. It allows us to estimate fluctuations in gravitational energy. The implementation of this algorithm offers the means of establishing the extent to which the Earth deviates from a state of hydrostatic equilibrium as a celestial body. Due to the aforementioned method, calculations have been conducted to validate its effectiveness and reliability. This example is given as an illustration of a given method for studying the internal structure of planets.

How lowermost mantle viscosity controls the chemical structure of Earth’s deep interior

Determining the fate of subducted oceanic crust is critical for understanding material cycling through Earth’s deep interior and sources of mantle heterogeneity. A key control on the distribution of subducted slabs over long timescales is the bridgmanite to post-perovskite phase transition in the lowermost mantle, thought to cause rheological weakening. Using high-resolution computational models, we show that the ubiquitous presence of weak post-perovskite at the core-mantle boundary can facilitate or prevent the accumulation of basaltic oceanic crust, depending on the amount of weakening and the crustal thickness. Moderately weak post-perovskite ( ~ 10–100× weaker) facilitates segregation of crust from subducted slabs, increasing basalt accumulation in dense piles. Conversely, very weak post-perovskite (more than 100× weaker) promotes vigorous plumes that entrain more crustal material, decreasing basalt accumulation. Our results reconcile the contradicting conclusions of previous studies and provide insights into the accumulation of subducted crust in the lowermost mantle throughout Earth’s history.

THE ROLE OF BIODEGRADABLE NONWOVEN FABRICS IN EFFICIENT SODDING OF EARTH STRUCTURES

Aim of the study: Newly formed earth structures such as ski slopes are areas causing difficulties in attempts for efficient sodding since colonization with plants, their initial development and adaptation are hindered due to unfavorable climatic and soil factors. The main aim of the study was to demonstrate the feasibility of using nonwoven fabrics made from sheep's wool and waste poultry feathers on steep-gradient mountain slopes. Material and methods: Biodegradable geotextiles can be used not only to protect seeds and soil from washout, but also to promote turf development and improve soil microbial quality. During the experiment, plant growth was monitored together with microbial frequency changes. Results and conclusions: The results showed that the application of nonwoven fabrics after sowing a mix of grasses and clover had many advantages including the acceleration of seedling germination, improvement of plant initial development and increase of the number of plants per m2. The final biostimulation effect was found to be strongly dependent on geotextile biodegradability, grammage and the fleece structure. The best yield was obtained with the nonwoven grammage within the range of 150 - 180 g·m-2. The promotion of plant growth and, in particular, the development of the root system had a significant positive impact on the population of soil microbiota.

MODEL PEMBELAJARAN INKUIRI TERBIMBING BERBANTUAN SCIENCE V-LAB PADA MATERI LAPISAN PERMUKAAN BUMI TERHADAP LITERASI SAINS SISWA SMP

ABSTRACT
 
 Scientific literacy skills are students' ability to draw conclusions based on scientific knowledge and communicate them orally or in writing. However, in reality the scientific literacy skills of students in Indonesia are still relatively low, therefore a learning model is needed that can improve students' scientific literacy skills, for example by using a guided inquiry learning model. This research aims to test the guided inquiry learning model assisted by science v-lab media on earth's surface layer material which can have an effect on increasing scientific literacy in junior high school students. This research is a quasi-experimental type with a post-test only control design located at SMPN 2 Panti Jember for grade 7 students. The results of the research are that the highest score in the experimental class is 91.66 with an average of 85.05, while the highest score is in the control class. namely 83.3 with an average of 66.40. So it can be said that the use of the guided inquiry learning model assisted by v-lab science media in learning material on the layers of the earth's surface has a significant effect on the scientific literacy abilities of junior high school students.