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Earth and environmental sciences cover all planetary and Earth science aspects, including solid Earth processes, development of Earth, environmental issues, ecology, marine and freshwater systems, as well as the human interaction with these systems.
Earth and Environmental Sciences
A történeti korokban élt emberek mindennapi élettevékenységét a háztartásrégészet egy adott emberi populáció hátrahagyott anyagi és építési kultúráján keresztül ítéli meg. A talajtanban alkalmazott talajkémiai és -fizikai paraméterek térhasználat elemzésben történő felhasználása ugyanezt a célt szolgálja, de természeténél fogva eltérő tevékenységek detektálására (is) alkalmas. A bemutatott vizsgálat két épületobjektum, talajtani alapokra helyezett, belső térhasználat elemzésének módszertani megfontolásait, illetve eredményeit foglalja össze. Győr–Ménfőcsanak-Széles-földek lelőhelyen feltárt kelta (La Tène kultúra, Kr.e. III. század második fele), illetve római kori bennszülött (Kr.u. I. század vége) épületobjektum belső terében, a teljes régészeti jelenségre reprezentatív horizontális mintavételi módszert alkalmaztunk, amelynek keretében 50×50 cm-es rácshálóból gyűjtöttünk antropogén üledékmintákat a két objektum belső teréből. A vizsgálat tárgyát képező objektumok méretben és felépítményben azonosságokat mutatnak. Az egyenként két ágasfás, félig földbe mélyített épületekből összesen 68 db mintán végeztünk talajtani méréseket [összes szervesszén-tartalom (TOC%), összes foszfortartalom (Pösszes), pH (H2O, KCl), CaCO3%, Arany-féle kötöttség (KA)]. Annak érdekében, hogy a régészeti jelenségekben megmutatkozó emberi hatást elkülöníthessük a környezeti háttérértékektől, a lelőhely négy pontján vettünk fel kontroll talajszelvényt. A régészeti környezetből származó mérési adatok kiértékelése kettős. Mennyiségi szempontból a lelőhely környezeti viszonyaihoz, illetve a kimért háttérértékekhez kell kalibrálni az adatokat. Minőségi szempontból ugyanakkor egy-egy paraméter mintasorozatában mért szórás, értékintervallum, illetve horizontális heterogenitása árulkodik az épület belsejének eltérő használatáról. Az alkalmazott paraméterek közül az összes foszfortartalom és az összes szervesszéntartalom adatai bizonyultak a leginformatívabbnak annak eldöntésében, hogy a vizsgált belső terek mely pontját, milyen mértékben érhette emberi tevékenységből származó behatás. Eredményeink alapján az Arany-féle kötöttségi szám, illetve a szénsavas mésztartalom eloszlásmintázatait – Győr–Ménfőcsanak-Széles-földek lelőhely esetében – csak részlegesen lehetett az egykori emberi tevékenységhez kötni. Ez a lelőhely szedimentológiai és talajtani viszonyaival magyarázható. A két objektum belső térhasználata, az antropogén üledékeken végzett talajtani mérések tanúsága szerint nem tekinthető azonosnak. A római kori bennszülött épület belső terében markáns különbséget lehet feltételezni a belső térhasználatban. Ezzel ellentétben a kelta épületobjektumnál egyenletes eloszlásmintázatról beszélhetünk, amely olyan emberi tevékenység egykori meglétére utal, amely nem szelektíven használta az épület belső terét.
A planetáris határréteg (PHR) és a talaj hidraulikus tulajdonságainak kapcsolatát elemeztük. Megkülönböztetett figyelemmel vizsgáltuk a PHR magasságának a talajadatbázistól függő talajparaméter-értékekre való érzékenységét. A szimulációkat az MM5 mezoskálájú rendszermodellel végeztük. A PHR magasságot a Janjic Eta- PBL és az MRF almodellekkel becsültük; a talajok hidraulikus tulajdonságait pedig a magyarországi és egyesült államokbeli talajadatbázisok alapján számítottuk. A modellterület Kárpát-medencét foglalja magában. Megtalálható benne Szlovákia jelentős része és a környező országok területei. Hat kiválasztott felhőmentes anticiklonális napot elemeztünk. Három napot (egy nyárit, egy őszit és egy télit) részletesen elemeztünk. A vizsgált napokon az erősebb besugárzásra kialakuló konvekcióban a talaj hidraulikus tulajdonságainak PHR-t módosító hatása is érvényesülhet. A futtatások időtartama 24 óra volt (0:00 UTC-és kezdéssel). Az érzékenységi vizsgálat eredményeit szignifikancia teszttel elemeztük. Az Eta PBL almodell használata során az összterület 60–90%-a mutatkozott szignifikáns érzékenységűnek (p < 0,01) a vizsgált hat napból öt napon. A szignifikáns különbséget mutató területek százalékos aránya csak a téli tesztnapon volt 50% alatti, ezt is csak az Eta PBL almodell alkalmazása során kaptuk. Ugyanezen a napon az MRF almodellel kapott százalékos arány 89% volt. A kapott különbségekkel kapcsolatban elmondható, hogy a PHR magasság változása nagyobb érzékenységet mutatott a PHR magasságát parametrizáló módszerekre mintsem a talajadatbázis használatára. Ennek ellenére megállapíthatjuk, hogy a talaj hidraulikus tulajdonságai nemcsak a csapadékos, hanem a csapadékmentes konvektív típusú időjárási helyzetekben is időjárás-alakító tényezőként hathatnak. Eredményeink a talaj–légkör kölcsönhatást jellemző folyamatok mezoskálájú modellezésében hasznosíthatók, ugyanakkor a talajfizika számára is tanulságosak, mert láthatjuk, hogy a talaj hidraulikus tulajdonságai nemcsak a talaj állapotát, hanem a talajjal határos szférák állapotát is bizonyos mértékig meghatározzák.
Munkánkban egy mezőföldi, döntően szántóföldi hasznosítású területen vizsgáltuk a vízerózió előfordulását, illetve a területhasznosítás és a potenciális erózióveszély egymáshoz való viszonyát. Az Előszállástól DNy-ra elhelyezkedő területet löszön kialakult mészlepedékes csernozjomok, a szélesebb völgytalpakon réti csernozjomok fedik, de a vízerózió bizonyítékaként a meredek völgyoldalakban földes kopárokat, illetve a lejtők alján lejtőhordalék talajokat találunk. A terület 1988–1989-es részletes talajtani felvételezésének adatait a Fejér Megyei Növény- és Talajvédelmi Szolgálat bocsátotta rendelkezésünkre. A 117 db pontszerű adatsor és az általunk szerkesztett digitális domborzatmodell segítségével megtörtént a talajtani adatok térbeli kiterjesztése és az erózió modellezéséhez szükséges raszteres térképállományok (agyagtartalom-, lejtőszög- és humusztérkép) előállítása. A területhasznosítási térképet 2005-ös légifényképek és 30 méteres felbontású Landsat TM műholdképek alapján készítettük el. Az átlagos éves talajveszteség meghatározásához az Egyetemes Talajveszteségi Egyenletet (USLE) használtuk. Az USLE alkalmazásában a legnagyobb bizonytalanságot jelentő K-faktor általunk kapott értékeinek realitását más szerzők (CENTERI, 2002) hasonló hazai területeken számolt értékeivel való statisztikai öszszehasonlításával ellenőriztük. A területre jellemző tényleges erózió mellett meghatároztuk a domborzati és talajtani adottságok által differenciált erózióveszélyeztetettséget is, amely gyakorlatilag a fekete ugaron tartott, szintvonalra merőleges művelés esetén bekövetkező eróziós rátát adja meg. A kapott eróziós értékek alapján három eróziós kategóriát különítettünk el, melyek között a határt 2 t·ha-1·év-1-nél, illetve 11 t·ha-1·év-1-nél húztuk meg. Az előbbi a hazai becslések szerinti szántóföldi művelés alatti, míg az utóbbi az USA talajvédelmi szakemberei szerinti optimális körülmények közötti éves talajképződési ütem. Munkánk gerincét az erózió-veszélyeztetettség és a tényleges talajeróziós mérték összehasonlítása jelentette. Megállapíthatjuk, hogy a mintaterületen a területhasznosítás jól igazodik a potenciális erózió-veszélyeztetettséghez, és a legjobban veszélyeztetett területeket erdők, cserjések vagy rétek borítják, melyek megfelelő védelmet nyújtanak a talajerózió ellen. Ugyanakkor a szántóföldeken – bár jelentős különbség mutatkozik a potenciális és a tényleges erózió között – még mindig 30% felett van a talajképződés ütemét meghaladó erózióval jellemezhető területek aránya. Ezekből a 11 t·ha-1·év-1-nél nagyobb talajveszteséggel rendelkező szántóföldek aránya csak 4%-ot tesz ki a szántókon belül. Ezek jobbára a völgyperemek „túlszántásából” adódnak. Bár a terület összességét tekintve a területhasznosítás alkalmazkodik az erózióveszélyeztetettséghez, sajnos feltételezhetjük, hogy ez inkább a vonalas erózió által kikényszerített felhagyás, mintsem USLE-alapú tudatos gazdálkodói döntés eredménye.
This paper presents the principles of a new inversion method used for the determination of 3D geological structures. The horizontal variations of the layer parameters i.e. layer thicknesses and resistivities are discretized in the form of series expansion. The unknown coefficients of the series expansion are determined by an iterative linearized inversion method using weights specified by the Most Frequent Value Method (MFV). The result of the inversion is estimated from the data of the bi-directional VES (Vertical Electric Sounding) measurements with Schlumberger array in each profile and in multiple profiles. A 3D Finite Difference method was applied to forward modelling, however, the structure is approximated along the profile with a 2D model discretized by single-variable series expansion. The 3D forward modeling procedure gives the opportunity to calculate data measured in two or multiple directions. The suggested interpretation method gives an approximate solution. Proceeding more accurate 3D inversion will be provided by the binary series expansion.
The paper presents the opportunities of archaeological applications of the geoelectric geophysical methods. The electrical conductivity properties of buried archaeological objects (wall relics, roads, channels, graves, metal objects, etc.) measurably differ from the electrical conductivity properties of soils and rocks covering archaeological objects. So these archaeological objects are detectable with geoelectric measurements performed on the surface of the Earth.The paper outlines the relation between the electrical parameters of individual archaeological objects and the medium covering them; and it supports the archaeological adaptability of geoelectric methods with the presentation of the results of field measurements.
This paper introduces the alternating conditional expectation (ACE) algorithm of Breiman and Friedman (1985) in multiple regression problems in groundwater monitoring data analysis. This special inverse nonparametric approach can be applied easily for estimating the optimal transformations of different groundwater monitoring data from the Bükk Mountains to obtain maximum correlation between observed aquifer variables. The approach does not require a priori assumptions of a mathematical form, and the optimal transformations are derived solely based on the groundwater data set. The advantages and applicability of the proposed approach to solve different multiple regression problems in hydrogeology or in groundwater management are illustrated by means of case studies from a Hungarian karst aquifer. It is demonstrated that the ACE method has certain advantages in some fitting problems of groundwater science over the traditional multiple regression.In the past, different groundwater monitoring data (like groundwater level, groundwater temperature and conductance, etc.) had been used for groundwater management purposes in the Bükk Mountains. One of the difficulties in earlier approaches has been the need to make some kind of assumption of the expected mathematical forms among the investigated reservoir and petrophysical variables. By using nonparametric regression, the need to assume a specific form of model is avoided, and a clearer vision of the relationships between aquifer parameters can be revealed in the Bükk Mountains, where karst water is the main source of potable water supply. Complex monitoring data from the Bükk Mountains were analyzed using the ACE inverse method, and results were verified successfully against quantitative and qualitative field observations.
The use of vertical electric dipole transmitter and receiver turns out to be advantageous in the exploration of lateral inhomogeneities of high resistivity layers by transillumination measurement. Geological information can be made clearer by transformation of the amplitude response to apparent resistivity spectrum. The apparent resistivity calculated by the geometric factor in the quasistationary frequency range depends decisively on the galvanic effect of the high resistivity layer containing the electrodes. In the so called frequency dependent inductive apparent resistivity deduced based on the amplitude response of the uniform half — respectively full — space at low frequencies mainly the effect of the shoulder formation, at frequencies high enough the effect of the resistive layer containing the electrode will dominate. The knowledge of these apparent resistivities on the one hand helps the determination of the effective resistivity, which is independent of the ray-length and indicates the continuity or discontinuity of the resistive layer along the equatorial plane. On the other hand in the case of transilluminations with areal coverage they can be used in the selection of the horizontal-layered, uniform start model, needed in the reconstruction of the spatial distribution of the resistivity-variation. Reconstructions of measured and simulated data demonstrate the applicability of the procedure.
All the elements of the Eötvös tensor can be measured by torsion balance, except the vertical gradient. The knowledge of the real value of the vertical gradient is more and more important in gravimetry and geodesy.Determination of the 3D gravity potential W(x, y, z) can be produced by inversion reconstruction based on each of the gravity data W z(= g) measured by gravimeters and gravity gradients W zx, W zy, W Δ, W xy measured by torsion balance. Besides vertical gradients W zz measured directly by gravimeters have to be used as reference values at some points. First derivatives of the potential W x, W y (can be derived from the components of deflection of the vertical) may be useful for the joint inversion, too. Determination of the potential function has a great importance, because all components of the gravity vector and the elements of the full Eötvös tensor can be derived from it as the first and the second derivatives of this function. The second derivatives of the potential function give the elements of the full Eötvöstensor including the vertical gradients, and all these elements can be determined not only in the torsion balance stations, but anywhere in the surroundings of these points.Test computations were performed at the characteristic region of a Hungarian plate area at the south part of the Csepel Island where torsion balance and vertical gradient measurements are available. There were about 30 torsion balance, 21 gravity and 27 vertical gradient measurements in our test area. Only a part of the 27 vertical gradient values was used as initial data for the inversion and the remaining part of these points were used for controlling the computation.
Statistical processing of engineering geophysical sounding data is applied to the determination of dry density as an important geotechnical parameter of shallow formations. Dry density has been measured in laboratory or in the field as point information. In order to get more extensive results, dry density is extracted from high-resolution penetration logs. Dry density is related to measured bulk density as well as porosity and shale volume computed directly from engineering geophysical sounding data. The most critical parameter for the calculation is water saturation, which is estimated by factor analysis of all penetration logs. This approach is based on a strong linear correlation between water saturation and one of the extracted variables (factors). The interpretation method is tested in twelve penetration holes drilled in a Hungarian location. A 2D multi-well application is presented, in which the spatial distribution of dry density between the drill-holes is given. A local relationship between bulk density and dry density is also estimated. The study demonstrates that dry density can be estimated as continuous and in-situ information to support geotechnical operations in soil environments.
This paper presents a new algorithm for the inversion-based 1D Fourier transformation. The continuous Fourier spectra are assumed as a series expansion with the scaled Hermite functions as square-integrable set of basis functions. The expansion coefficients are determined by solving an over-determined inverse problem. In order to define a quick and easy-to-use formula in calculating the Jacobi matrix of the problem a special feature of the Hermite functions are used. It is well-known, that the basic Hermite functions are eigenfunctions of the Fourier transformation. This feature is generalized by extending its validity for the scaled Hermite functions. Using the eigenvalues, given by this generalization, a very simple formula can be derived for the Jacobi matrix of the problem resulting in a quick and more accurate inversion-based Fourier transform algorithm. The new procedure is numerically tested by using synthetic data.
The results of model calculation (direct problem solutions above model parameter space) determine an embedded continuous and differentiable surface in the Euclidean space of measurements. This multidimensional subspace contains the possible expected values of measurement vectors according to the assumed rock model as a projection of measurement points (expressing the model and real rock equivalences). The model parameters are the natural coordinates of this subspace, determining a contravariant curvilinear coordinate system (“flat world” for the inversion). The local curvature of this surface is very important factor of covariance matrices and the possible bias of estimated parameters. In this article the role of curvature is discussed and the shortage of conventional (first order) inversion is demonstrated by simple example and the possibility of bias correction.
In this study we interpret the magnetic anomalies at satellite altitude over a part of Europe and the Pannonian Basin. These anomalies are derived from the total magnetic measurements from the CHAMP satellite. The anomalies are reduced to an elevation of 324 km. An inversion method is used to interpret the total magnetic anomalies over the Pannonian Basin. A three dimensional triangular model is used in the inversion. Two parameter distributions, Laplacian and Gaussian are investigated. The regularized inversion is numerically calculated with the Simplex and Simulated Annealing methods and the anomalous source is located in the upper crust. A probable source of the magnetization is due to the exsolution of the hematite-ilmenite minerals.
Wireline logging surveys are routinely used for the reconnaissance and quantitative characterization of multi-mineral hydrocarbon structures. The interpretation of well-logging data, however, is quite a challenging task, because the conventionally used local inversion procedure becomes either an underdetermined or a slightly overdetermined problem that may result in poor parameter estimation. In order to determine the petrophysical model composed of several parameters, such as specific volumes of matrix components, water saturation, primary and secondary porosity and numerous zone-parameters, in a more reliable way a new inversion methodology is required. We suggest a joint inversion technique for the estimation of model parameters of multi-mineral rocks that inverts data acquired from a larger depth interval (hydrocarbon zone). The inverse problem is formulated assuming homogeneous intervals within the zone to get a highly overdetermined inversion procedure. The interval inversion method has been applied to shaly sandy hydrocarbon reservoirs, in this study, that is used for the estimation of petrophysical parameters of complex reservoirs. Numerical results with synthetic and field data demonstrate the feasibility of the inversion method in investigating carbonate and metamorphic structures.
In this study we introduce new rock physical models which describe the pressure dependence of seismic velocity and quality factor. The models are based on the idea (accepted in the literature) that microcracks in rocks are opened and closed under the change of pressure. The models were applied to acoustic P wave velocity data measured on core samples originated from oil-drilling wells (27 samples) and also seismic velocity and quality factor data sets published in international literature. During the measurements the pulse transmission and the spectral ratio techniques were used. Measurements were carried out at various incremental pressures and parameters of the models were determined by linearized inversion methods. The calculated data matched accurately with measured data proving that the new rock physical models apply well in practice.
The paper discusses the characteristics and feasibility of a multilayer kinematic refraction inversion method that is applicable to estimate the — even laterally changing — parameters of a geological model in the simultaneous evaluation of refraction data. The studied method has been developed at the Department of Geophysics of the University of Miskolc for the interpretation of parameters (layer thicknesses and seismic velocities) using series expansion based on adequately chosen basis functions. Besides revealing its resolution properties, ambiguity studies are also presented on synthetic data sets. In the terminology of refraction inversion uncertain and ambiguous results are frequently encountered problems in multilayer cases when all parameters (or all coefficients describing the parameters) are estimated simultaneously in the same inversion procedure. Results of resolution and ambiguity analyses of synthetic data sets and field examples are shown in this study.
Nowadays, GPS is the best positioning system with its constellation, but number of GLONASS satellites increased to the required number, with launched new ones, for positioning. With recent revitalization of GLONASS, a great number of high precision GLONASS and GPS/GLONASS receivers have been produced. In this paper, baselines of two networks have been analyzed in order to assess the usability of GLONASS on global positioning. In both networks, repeatabilities of results were investigated by using GPS, GLONASS and GPS/GLONASS data. Results revealed that repeatabilities of all baselines by using GLONASS observations are not consistent when compared to the GPS and GPS/GLONASS.
Estimation of precipitable water vapor (PWV) in the atmosphere using ground based GPS (Global Positioning System) data requires an appropriate model for computation of zenith hydrostatic delay (ZHD). Presented herein is a site-specific ZHD model (SSM) for a station at New Delhi, India. The model has been developed by regressing one-year atmospheric vertical profile data collected through radiosonde. The model based on surface atmospheric pressure at the station, has been validated invoking data of three more years. The ZHD values estimated through the model disagree at the 0.3 mm level with ZHD values obtained from raytracing of radiosonde data. Further, Saastamoinen ZHD model provides an error about 0.23 mm rms while about 0.19 mm by the developed model (SSM). Thus, developed SSM can be used for precise estimation of PWV.
Soft computing techniques are widely used for the applications on most of the nonlinear problems related to the real world. Earth’s most of the nonlinear characteristics exhibit the uncertainty problem that has to be interpreted with most of the advanced soft computing tools. Here the three layer electrical resistivity data has taken for interpreting the subsurface parameters of the earth using Adaptive Neuro-Fuzzy inference (ANFIS) technique. ANFIS can be predictably used for most of the nonlinear problems. Its membership functions and rules with adjustable parameters will help the interpretation technique with less error percentage results. In the present study, the program is specially designed for the interpretation of three layer electrical resistivity data. The network model is successful in training with large number of data sets available. Interpretation using ANFIS technique will give the promising results with good accuracy. With much less error percentage, the program supports all types of three layer electrical resistivity data more than a conventional method can do. Typical problems with parameter estimation can be done more efficiently with this ANFIS program.
Nowadays, the Continuously Operating Reference Station (CORS) network, combined with network RTK corrections (NRTK solution), is a widely used technique for high-accuracy positioning in real time. This “active” network realizes a reference frame and propagates it to the users. In border regions the coherence between the reference frames propagated by neighboring active networks is a critical problem. In this study the test results of post-processed and simultaneous NRTK positions at six test points located in the border region between Portugal and the Community of Andalusia, in the south west of the Iberian Peninsula, are presented. The analysis is based on two GNSS active networks present in this border region, namely RENEP (Portugal) and RAP (Community of Andalusia, Spain), a national and a local RTK network respectively, with similar characteristics. Upon comparing the post-processed position for each test point, as estimated with respect to each of the two active networks analyzed, the discrepancies found in 3D were less than 2 centimeters. The results of network-based RTK positioning were found to be successful within a 2 cm precision level in the east and north components and 4 cm for the up component. The results also confirm that the NRTK positioning accuracy is about 2 cm in horizontal and 4 cm in vertical, which can satisfy the requirement of real-time positioning users at a centimetric accuracy level, even in border regions considering extrapolated NRTK solutions.
The multifractal analysis is applied to the study of geomechanical monitoring time series. Estimation of singularity spectra parameters within moving time window for this monitoring time series provides a possibility for splitting the history of observations into few adjacent fragments which could reflect e.g. hidden different states of the rock massif in the vicinity of measuring station. In this contribution, analysis of time series of measured distances is presented. A laser distance meter is used for measuring the height of a large chamber in the medieval Jeroným Mine (Czech Republic). This time series separation into individual segments using singularity spectra parameters is important for possible comprehensive analysis of data in individual time periods and/or between individual time periods.
The Earth topographic masses are compensated by an isostatic adjustment. According to the isostatic hypothesis a mountain is compensated by mass deficiency beneath it, where the crust is floating on the viscous mantle. For study of the impact of the compensating mass on the topographic mass a crustal thickness (Moho boundary) model is needed. A new gravimetric-isostatic model to estimate the Moho depth, Vening Meinesz-Moritz model, and two well-known Moho models (CRUST2.0 and Airy-Heiskanen) are used in this study. All topographic masses cannot be compensated by simple isostatic assumption then other compensation mechanism should be considered. In fact small topographic masses can be supported by elasticity of the larger masses and deeper Earth’s layers. We discuss this issue applying spatial and spectral analyses in this study. Here we are going to investigate influence of the crustal thickness and its density in compensating the topographic potential. This study shows that the compensating potential is larger than the topographic potential in low-frequencies vs. in high-frequencies which are smaller. The study also illustrates that the Vening Meinesz-Moritz model compensates the topographic potential better than other models, which is more suitable for interpolation of the gravity field in comparison with two other models. In this study, two methods are presented to determine the percentage of the compensation of the topographic potential by the isostatic model. Numerical studies show that about 75% and 57% of the topographic potentials are compensated by the potential beneath it in Iran and Tibet. In addition, correlation analysis shows that there is linear relation between the topographic above the sea level and underlying topographic masses in the lowfrequencies in the crustal models. Our investigation shows that about 580±7.4 metre (in average) of the topographic heights are not compensated by variable the crustal root and density.
Mars Orbiter Laser Altimeter (MOLA) team discovered “the striking difference” in elevation between northern and southern hemispheres: “on Mars, the South Pole lying about six km higher than the North Pole, … the planet’s center of mass (is) 3 km north of its geometric center” (Physics Today, Oct 1999, p. 34). The same topography we have for solid Earth: low Arctic and high Antarctic with the same difference 5–7 km. No sound explanation of NS asymmetry was proposed: impact, planetary evolution, mantle convection … are rather artificial and vague. Meanwhile, NS asymmetry is inherent property of any freely rotating flexible celestial body as it follows from Kozyrev’s Causal or asymmetrical mechanics. Relations of Causal mechanics are supported by experimental study of vertical component of causal force by weight change measurement of rotated gyroscope and the study of its horizontal component by pendulum deflection measurement. Kozyrev made measurements at latitudes φ from 45° to 84° and proved that causal force is directed along Earth rotation axis: to the North for φ < 73° and to South for φ > 73°. The magnitude of causal force has order (1–5) × 10−5 of gravity force.
The results of measuring elevations leveling using an optical beam straightness, contain, besides the desired constant height, variable part caused by the influence of refraction. The latter has traditionally been seen as an error (random and partly systematic). However, these “errors” due to physical causes, are not subject to statistical regularities, but because they can not provide a mean-square error. Fluctuations in the heights under the influence of refraction caused by physical laws, which makes use of classical methods to evaluate the accuracy and altitude adjustment flawed.
In precise geoid modelling the combination of terrestrial gravity data and an Earth Gravitational Model (EGM) is standard. The proper combination of these data sets is of great importance, and spectral combination is one alternative utilized here. In this method data from satellite gravity gradiometry (SGG), terrestrial gravity and an EGM are combined in a least squares sense by minimizing the expected global mean square error. The spectral filtering process also allows the SGG data to be downward continued to the Earth’s surface without solving a system of equations, which is likely to be ill-conditioned. Each practical formula is presented as a combination of one or two integral formulas and the harmonic series of the EGM.Numerical studies show that the kernels of the integral part of the geoid and gravity anomaly estimators approach zero at a spherical distance of about 5°. Also shown (by the expected root mean square errors) is the necessity to combine EGM08 with local data, such as terrestrial gravimetric data, and/or SGG data to attain the 1-cm accuracy in local geoid determination.
In the community of geodesy it is well-known that the famous normal distribution is originated from the mathematical analysis of observational errors in astronomical and geodetic measurements.However, as far as we know this aspect of scientific history which is of considerable interest for the community of earth sciences has rarely been considered in the literature of earth sciences.In geodesy and related areas the bivariate normal distribution is one of the most frequently used probability distributions. Nowadays, in a wide range of problems arising from diverse areas of geodesy, geophysics, photogrammetry and astronomical geodesy we encounter numerous applications of the univariate and multivariate normal distributions.In the present paper the historical role of earth sciences in the origins of the bivariate normal distribution is briefly discussed. Some new evidences of Bravais’ contribution to the origin of the correlated bivariate normal distribution are considered. The new evidences and refinements established in this paper convey such a general methodological and intellectual content that is useful for the community of geodesy, geophysics, and furthermore in earth sciences.
Abstract
The mineralogical museum of the Collegio Nazareno of the Piarists Order in Rome was founded by Gian Vincenzo Petrini c. 1760. It hosted minerals and rocks the Popes had received as gifts and given to Piarists to support their teaching, as well as minerals collected from Roman and Neapolitan volcanoes. On March 24, 1769, the museum was visited by Emperor Joseph II, officially there as an incognito tourist but, in fact, to organize the election of a Pope who would abolish the Jesuit Order. On June 14, 1785 the Emperor, by now King of Hungary as well, presented eight crates of minerals from mining areas in Transylvania and Upper Hungary, i.e. Slovakia. This collection had been organized by “Baron of Born”, who also wrote down descriptions of all the specimens (mostly ores), as referred to in Petrini (1791–92). The museum of the Collegio Nazareno has survived and the royal gift is partially preserved, curated by the Gruppo Mineralogico Romano (GMR), a private association of amateurs founded in 1982. The museum now exhibits a rare collection of minerals from 18th century central Europe, organized according to systematics that just preceeded the major scientific changes brought about in mineralogy by the crystallographic approach.
Abstract
The Tokaj Mts, situated in the northeastern part of the inner arc of the Carpathians, forms a part of a Miocene calc-alkaline andesitic-dacitic-rhyolitic volcanic island arc. The ancient volcanic structures were reconstructed on the basis of the 1:50 000-scale and 22 sheets of the 1:25 000-scale geologicpetrologic maps, as well as the revision of the volcanic facies in 150 boreholes. Multispectral and SAR satellite imagery, aerial photos, data and maps of airborne geophysical surveys (magnetic and radiometric), gravity-filtered anomaly maps, geochemical (soil and stream sediment Au, As, Sb, Hg) concentration distribution maps and the K/Ar dating of 132 samples from 80 paleomagnetic measurements were also used.
The anomalies were only taken into consideration in the interpretation if the coincident results of at least 3 methods indicated the presence of any volcanic structure. In consequence, 91 map-scale volcanic structures were identified by morphology — complex calderas, single lava domes, volcanic fissures, subvolcanic intrusions, diatremes, stratovolcanoes and postvolcanic formations. Conclusions were also drawn regarding the link to the volcanic structures and prospective occurrences of the mineral resources of the Tokaj Mts: andesite, dacite, welded zeolitic tuff, K-metasomatite, perlite, pitchstone, pumice, bentonitic, illitic, kaolinitic, diatom-bearing and silicified lacustrine sediments, hydrothermal Au-Ag and Pb-Zn veins, and Hg stockwerks.
Abstract
The Sanandaj-Sirjan granitoids (SSG) in western Iran are composed mainly of granite, granodiorite and tonalite. Chemically the rocks are peraluminous and metaluminous, and show S-and I-type characteristics. The oval shape of the plutons, with large axes parallel to the Zagros main trend, along with deformational textures and structures, the existence of aluminous minerals such as andalusite, garnet and sillimanite as well as micaceous enclaves and geochemical features, all support generation of these rocks by partial melting of heterogeneous source materials in a continental collision setting, corresponding to the Zagros Orogen.
Abstract
We investigated three types of shocked feldspar in the Asuka-881757,531-2 sample with midinfrared spectroscopy (reflectance mode). Under the petrographic microscope three types of site were characterized by (1) undulatory extinction, (2) undulatory extinction with isotropic patches and decreased interference color, and (3) isotropic, lath-shaped feldspars, which is indicative of maskelynite. The IR emissivity maximum (Christiansen feature=CF) changes with the chemical composition of feldspar. One of the Christiansen composition features exhibits a wave length peak of 1234 cm−1 for anorthite; another feature appears at 1245 cm−1 for maskelynite (Palomba et al. 2006).
With the help of IR spectroscopy we observed three vibrational types in our spectra: (1) peaks of depolimerization of SiO4 tetrahedra (500–650 cm−1, 950–1150 cm−1), (2) peaks of stretching and bending vibrational modes of SiO6 octahedra (750–850 cm−1), and (3) Si-O stretching vibration of SiO4 units (Johnson and Hörz 2003; Johnson et al. 2003, 2007). All these vibration types were observed at the less shocked sites. In the spectrum of highly shocked maskelynite only a broader band close to 1000 cm−1 was observed, which is the main vibrational band of maskelynite (Palomba et al. 2006). The calculated FWHM showed the disordering rate of shocked feldspars. On the basis of the measurements it could be concluded that the estimated shock pressure range gradually increases from 17–35 GPa for different degrees of undulatory sites, to 35–45 GPa for maskelynite sites.
Abstract
The Kiskunhalas-NE (KIHA-NE) fractured hydrocarbon reservoir is part of the structurally rather complex crystalline basement of the Great Hungarian Plain. In the course of petrologic and thermometric examinations various rock types of the investigated area have been classified and characterized. There are four basic lithological units in the area. In the lowest structural position orthogneiss is common, which according to its petrographic features is assumed to be identical to the orthogneiss body of the adjacent Jánoshalma (JH) basement high (metamorphic peak temperature T < 580 °C according to Zachar and M. Tóth 2004). The next rock unit upward is the highly mylonitized variety of the orthogneiss with textural features suggesting deformation in an extensional stress regime. In the higher section of the mylonite zone graphitic gneiss mylonite is characteristic, with a peak metamorphic T of 410±45 °C. The lithology in the shallowest position of the area is a graphitic carbonate phyllite, with a T of 375 ± 15 °C. Estimation of the deformation temperature for both mylonitic rocks results in approximately Tdef ∼ 455 °C. All data together suggest that between the top (graphitic carbonate phyllite) and the bottom (orthogneiss) of the ideal rock column there is about 200 °C peak metamorphic temperature deviation. The two extreme metamorphic blocks probably became juxtaposed along an extensional fault zone in the basement at approximately 15 km depth.
Abstract
We studied optical microscopic and micro-Raman spectroscopic signatures of shocked olivine from the ALH 77005 Martian meteorite sample. The purpose of this study is to document pressure and temperature-related effects in olivine over the entire sample, which can aid in understanding structural changes due to shock metamorphism and the post-shock thermal annealing processes of lherzolitic Martian meteorites. According to the optical microscope observations, three areas may be discernible in olivine of the ALH 77005 in the vicinity of the melt pocket. The first area is the thermally undisturbed part of a grain, which contains a high density of shock-induced planar microdeformations such as Planar Deformation Features (PDFs) and Planar Fractures (PFs). Compared to the first area, the second area shows less shock-induced microstructures, while the third area is a strongly recrystallized region, but not formed from a melt.
A common Raman spectral feature of these olivines is a regular doublet peak centered at 823 and 852 cm−1; additionally, two new peaks at 535 and 755 cm−1 appear in the weakly annealed transition zones.
This is a brief history of how a small group of people carried out its mandate to survey and map Canada in spite of the hostile environment — the second largest country in the world — in a 100 years.The levelling started from Halifax and by 1916 it reached Vancouver completing the coast-to-coast connection, encompassing about 22 000 km distance of which 94% was done on the railway tracks. The adjustment was carried out in 9 steps, it included the tide gauges in both the east and west coast, and was completed in 1928. The final adjustment used about 37 000 km length, from which 30 000 was measured by the GS. The first order re-levelling started after the Second World War and was carried out on the Trans-Canada highway. By 1994 Canada was covered by a levelling network of about 109 747 km. After this date there was no more conventional levelling.The triangulation used cross-braced quadrilaterals, based on the method used in the USA. In 1961 the GS started to use the conventional methods of chains of triangles. The measurements covered mostly the very southern part of Canada. The mapping of middle and northern part of the country had to await until the electronic era, which was practically made for Canada.The lower order accuracy was provided by Shoran, using about the average of 400 km line length for triangulation. Between 1947 and 1957 this method provided 501 measured triangle sides of about 200 000 km in total length and provided 119 base-point covering about 65% of Canada.The other method, the Aerodist — the Tellurometer version of Shoran — provided second order accuracy. The triangulation, using cross-braced quadrilaterals, with 100 km sides gave 219 points and covered about 25% of the land area of Canada. The measurements were done between 1965 and 1973.Recent measurements make use of GPS for geodetic position determination. A 10 year program started in 1987. In 1992 the GSD defined an official geoid to be used in connection with all satellite work.
The paper presents field results of the data processing method developments based on approximate TAU-transform of the Time-Domain IP (Induced Polarization) curves. The theoretical basis of these developments was published in Part I by Turai and Dobróka (2011).Two ways for estimation of the type and the value of soil contaminations will be introduced. On first way the calculation of contamination type comes from the time constant value of the time constant spectra. The value estimation of the soil contamination is based on the Weighted Amplitude Value (WAV) of the time constant spectra. On second way we define the corrected apparent conductivity of the contaminated material (σ corr) as a product of time-constant spectrum and measured apparent conductivity. The σcorr parameter is useful for classification of contamination level.These methods were tested over several contaminated area (Offheim — 1992, Nyékládháza — 1997–2008, Ráckeve — 1997, Kecskemét — 1997, Győröcske — 1999, Pásztó — 2000, Tokaj — 2001, Balmazújváros — 2002, Szerencs — 2004, Tiszapalkonya —2004, Berekböszörmény —2007, Nagytárkány —2008, Darvastó — 2008, Miskolc-Hejőpart — 2008, Tiszavasvári — 2008, Nagytétény — 2008, Miskolc-Bedő hegy — 2009, Telkibánya — 2010, Miskolc-Salakbánya — 2010, Miskolc-Gózon L. út — 2010 and Miskolctapolca-Várhegy — 2010).Some results from interpreting field data collected over waste sites and other contaminated areas are presented. The contamination level and the main components of the contaminating material are characterized based on the time-constant spectra.
Topographic masses have a strong impact on the medium and short wavelength components of the gravitational signal generated by the mass of the Earth, thus digital terrain models (DTM) are routinely involved in gravity field modelling. In this study the verification of the Shuttle Radar Topographic Mission (SRTM) and the Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM) which is a joint product of METI (Ministry of Economy, Trade and Industry of Japan) and NASA has been done by comparing them to the points of the horizontal and vertical control networks of Hungary. SRTM data fit better to geodetic ground control points than ASTER GDEM, since some artefacts have been found in ASTER elevation set which impede further use of the latter without any pre-processing. Since SRTM is an “unclassified” surface model including all those points which reflected the scanning radar signal thus tree canopy height has been compared to the differences of SRTM and DTM elevations in a hilly test area in Hungary where a local and accurate DTM having 20 m × 20 m horizontal resolution was available. Considerable agreement was indicated between forest height and model differences. Model differences were evaluated to determine their effect synthetically on gravity related quantities. Their influence on geoid height is insignificant, but the change of the investigated second derivatives of the potential is considerable.
In the last decades many statistical tests based on the least squares solution have been proposed for multiple outlier detection. All of them suffer, however, from deficiencies that make them inefficient in their practical application. As recently demonstrated by the author, this situation is unavoidable in the framework of least squares theory. The present contribution elaborates on this impossibility of obtaining an unambiguous response for any statistical test based on the least squares solution and makes use of multiple least squares adjustments for statistically characterizing the equivalent sets of multiple gross error vectors. Several examples and a flexible Matlab implementation are provided.
Pesticides, chlorinated organic compounds and hydrocarbons are among the most threatening soil and groundwater contaminants because of their mobility and persistence in the subsurface, their widespread use, and their health effects. Hazardous chemicals getting into underground medium can be especially dangerous because they may remain persistently hidden from human eyes for a long time and their harmful impact on health may appear much later than their emission time and spatially far from the source of contamination. Development and combination of reliable and accurate geophysical methods and hydrogeological transport models with the traditional chemical analytics are greatly needed to assess the risk posed by the contamination plumes of these compounds to the subsurface.The paper presents the successful cooperation of these three disciplines in detailed characterization of subsurface hydrocarbon contaminants in a test site of Hungary. Combining the chemical analysis with high resolution geophysical methods and hydrogeological transport modeling the 4 dimensional characteristics of the contamination can be produced. The interdisciplinary research produced new developments and results in all participating fields of sciences.
In this paper we provide a comprehensive summary about the practical results of the OTKA project K49604. 1. We calculated the consequences of incorrect positioning of the electrodes for various multielectrode systems. In practice these effects were found to be negligible. The only exception is the case of rocky surface, where it is impossible to put the electrodes in the desired positions. The errors can however be kept within an acceptable range, if the electrodes of the linear arrays are put off-set, at right angles from the measuring line. A five-six times larger off-set has less effect than a certain mis-position along the line, connecting the electrodes. 2. We carried out tensorial geoelectric measurements around the Cistercian Monastery at Pilisszentkereszt. Areal measurements provide much more detailed and unambiguous anomalies than 2D profile measurements, and the tensor invariant representation of apparent resistivity anomalies provides a realistic picture about the lateral variation of the subsurface resistivity, even in field circumstances. 3. We tested the applicability of 3D electrical resistivity tomography (ERT) technique to detect landmines in different soil conditions and at various depths. Metallic and non-metallic landmines buried in wet and dry soils had been synthetically modeled. According to the inverted resistivity data using the dipole axial array in wet environment, it was possible to locate the metallic and non-metallic landmines as long as the noise level was about 5%. 4. We elaborated moreover a geoelectrical procedure which is able to map multidirectional fissure systems by combining geoelectrical profiling and geoelectrical azimuthal measurements. Results received by using both the so-called null-, and traditional arrays were jointly interpreted. The humidity of the fissures affects the measured results significantly, and in a meaningful way. 5. We presented the socalled standardized pricking probe (PP) surveying technique and demonstrated its usefulness in an archaeological study. The PP images proved to be definitely more close to the realistic shape of the buried chapel than the geoelectric and magnetic measurements, and they also revealed more details about the subsurface than the georadar. The optimum PP parameters: horizontal interval, pricking depth, observable quantity and its way of presentation were optimized through field experiments. For more details see the cited publications. The figures ever published in Hungarian journals are not reproduced here.
A new quasi-geoid model for Hungary was determined by combining gravity data, GPS/levelling and vertical deflections. Reduction of the measurements was performed by using Earth Gravitational Model 2008 (EGM2008) and Shuttle Radar Topographic Mission (SRTM) elevation data sets. Calculation method was Least Squares Collocation (LSC) with self-consistent planar logarithmic covariance model. In the computations the weights of GPS/levelling data were large, in this way normal heights obtained from levelling are consistent with GPS heights and with the quasi-geoid model. Astrogeodetic-gravimetric, pure astrogeodetic and pure gravimetric solutions have been calculated besides the combined solution to investigate the discrepancies among the different models. The combined quasi-geoid model fits to the GPS/levelling data with standard deviation of ±4.9 cm, nevertheless at some GPS/levelling sites large differences were indicated.
In the global navigation satellite system (GNSS) carrier phase data processing, cycle slips are limiting factors and affect the quality of the estimators in general. When differencing phase observations, a problem in phase ambiguity parameterization may arise, namely linear relations between some of the parameters. These linear relations must be considered as additional constraints in the system of observation equations. Neglecting these constraints, results in poorer estimators. This becomes significant when ambiguity resolution is in demand. As a clue to detect the problem in GNSS processing, we focused on the equivalence of using undifferenced and differenced observation equations. With differenced observables this equivalence is preserved only if we add certain constraints, which formulate the linear relations between some of the ambiguity parameters, to the differenced observation equations. To show the necessity of the additional constraints, an example is made using real data of a permanent station from the network of the international GNSS service (IGS). The achieved results are notable to the GNSS software developers.
Abstract
The article offers a general overview of risk assessment in the environmental and Earth sciences. To begin with natural and man-made hazards are discussed, followed by general definitions and the treatment of uncertainty and risk. The main steps of risk assessment in the Earth sciences are discussed step by step. Finally, the problems of decision-making are briefly treated. To assist the interested reader a comprehensive list of essential references is also presented.
Abstract
The River Tisza is one of Central Europe's most important rivers. In the last one and a half century numerous anthropogenic activities have influenced its watershed. As a result measures need to be taken to protect its water quality, necessitating a comprehensive picture of the spatial and temporal variability of its processes, which this study aims to extend further. In this study five sampling locations were analyzed in the upper section of the Tisza over the time interval 1974–2005, dealing with 24 parameters using multi-variate data analysis methods. Employing time series analysis and taking the river's tributaries into account, the strong influence of the River Szamos was pointed out, while stochastic connections indicated the influence of the Tiszalök Water Barrage System on the spatial variation of the Tisza's processes. Finally, by using principal component analysis (PCA), the different background factors were revealed in space and time (seasonal separation) as well. During summer the processes tended to be nitrogen-related, while during winter inorganic compounds play a greater role. Most importantly, spatial variety was observable in the factors.
Abstract
Compet-Terra is carrying out QA (Quality Assurance) services for the Hungarian Agriculture and Regional Development Agency. Quality control of the LPIS is one of the important QA duties. The LPIS data set is updated yearly according to the cycles of agricultural subsidies. Compet-Terra elaborated an Open Source Software based checking method that could be adopted by the client without the financial expense of software.
QuantumGIS (as the primary tool), gvSIG, and LibreOffice were used for the quality control of the LPIS. Four primary quality types were checked: (1) the land parcel attributes, (2) the areas of the polygons, (3) the completeness of the content and (4) the topological quality. For these investigations topological GIS functions and database management functions were used. The most important functions were topological difference calculation, polygon area calculation and geometry validity check. Complex procedures were also carried out with proprietary tools to compare the results and the run-time performances.
The result of the adoption of OSS GIS tools for LPIS checking was positive. All the planned procedures could be implemented using OSS GIS. OSS tools proved to be robust, reliable, userfriendly and performed well.
Maulbertsch öröksége és a szombathelyi székesegyház mennyezetképei 1. Winterhalder mint Maulbertsch legjobb tanítványa – a szentély Angyali Üdvözlet-kompozíciója
The Legacy of Maulbertsch and the Ceiling Frescoes of Szombathely Cathedral 1. Winterhalder as Maulbertsch's Best Pupil – The Annunciation Composition of the Chancel
Abstract
The author devotes a series of articles to the iconographic and pictorial specificities of the perished ceiling frescoes of Szombathely cathedral. The frescoes were painted on the basis of Franz Anton Maulbertsch's sketches after his unexpected death by Joseph Winterhalder jr. and after the latter's death, by Anton Spreng between 1798 and 1808. Each of the three great frescoes has a different relationship with Maulbertsch's sketches and his concept of ceiling decoration, and in the course of the execution of the work Winterhalder, “the best pupil of Maulbertsch” also changed his attitude to the ongoing work.
The present paper introduces the first piece of the cycle, the Annunciation in the chancel. After Maulbertsch's death Bishop János Szily asked Maulbertsch's father-in-law the engraver Jakob Schmutzer to find a competent fresco painter. He recommended Winterhalder, reporting in enthusiastic terms about the striking resemblance of his style with Maulbertsch's. As the sources reveal, the client did not want to find a Maulbertsch imitator at first and would have respected the artistic originality of the new painter. He was not aware that Winterhalder's successes as a fresco painter were largely due to his ability to reproduce and vary the formal and compositional solutions learnt from his master. After arriving in Szombathely, the painter assured the bishop to continue the original concept of Maulbertsch and not to work after own invention.
When Winterhalder began decorating the chancel ceiling, he had a lot of work ahead on the basis of the bozzetto he received. It was exceptionally rare that Maulbertsch elaborated a detailed design corresponding exactly with the final composition. Usually he only determined the foci of the composition and the protagonists, adding the details ad lib on the ceiling, drawing them in free hand with the brush. Having learnt this method working in Maulbertsch's workship, experienced Winterhalder seems to not have been perplexed by the job of filling the huge vault with a rich composition whereas the sketch only contained the chief motifs. Apart from the bozzetto, another source of the Maulbertschian motifs was a work in Moravia, the central ceiling fresco in the nave of the church of Dyje (Mühlfraun). Winterhalder, too, had been involved in the execution of the fresco and – just like in many other places – he probably made ricordi of Maulbertsch's composition and figural groups, which he must have found appropriate to be used in Szombathely as well. The figure of the adoring angel leaning over a cloud or Saint Michael sitting in contrapposto are exact borrowings from Dyje, and the basic concept of the composition also derives from there. The female figures of the Old Testament in the window zone are also based on another Maulbertsch work, the figures of the Carmelite church in Székesfehérvár.
Winterhalder also relied on his own imagination. It is to the credit of his inventiveness that he turned a biblical scene of meagre external features into a dramatic scene filling a whole vault. On the basis of the Tridentine representations of the Annunciation, he fully exploited the possibilities of the theological metaphors with a huge host of angels, an array of different symbols to enrich the iconographic arsenal of the scene. The foundation for this was Winterhalder's great theological culture and ability to invent symbols, which are obvious in other works of his as well.
Thus, in the first phase of the commisson – the decoration of the ceiling of the chancel – Winterhalder apparently acted as the talented pupil of Maulbertsch in confirmation of his fame. He eminently rehearsed what he had learnt about the elaboration of a sketch and the incorporation of pictorial panels. He dazzled his client – like so many times earlier – by creating a “real” Maulbertsch work. The next phase of the work – the decoration of the central dome – was a more taxing task confronting the painter with a new challenge.
Abstract
Miocene siltstone with variable sand content and bentonitic clay is the most abundant sediments encountered at the metro construction site at Rákóczi Square (Budapest). Core logs, drilling reports and records of laboratory analyses were studied to better understand the local geology and to prepare a database on engineering geologic properties of the materials. Using this database, geologic sections were prepared and geomathematical methods were used to obtain a better correlation of the strata in the area and a reconstruction of the geologic evolution of the area. The samples were divided into five groups based on physical properties. These five parameters allowed the use of multivariate statistical methods as cluster and discriminant analysis. As a result it was possible to identify several types of lithotypes, including two bentonitic clays with substantially different properties, one fat clay, one medium clay and one sandy, lean clay and siltstone group.
Abstract
Over the years many studies have been conducted to understand the delta system of the Algyő field, many of them dealing with the Ap-13 reservoir. In the present study, therefore, several papers have been reviewed and analyzed to provide the basis for a more detailed description of this reservoir.
A macro-scale sedimentological model was developed using Markov analysis. Golden Software's Surfer 8.1 and Strater were used to construct the maps and to define the vertical sedimentological facies of the A-993 borehole. The mega-scale sedimentological 3-D model and the petrophysical parameters of 144 boreholes were analyzed using the Rockware RockWorks 15 and SPSS software.
It is concluded, when comparing the vertical section of the A-993 borehole (from the core description) with the sand content from the 3-D model at similar depth, considering the results of the embedded Markov model and the 3-D sedimentological model, that the reservoir is a deep-marine sand body, with a sand content less than 55% and siltstone content of around 30%. It is characterized by the features of proximal middle fan systems.
Abstract
The Bjelovar Sub-basin is situated in Northern Croatia and constitutes the southwestern branch of the Drava Basin. The Neogene-Quaternary sedimentary section can be subdivided into three megacycles, which are separated by regional unconformities. The data analyzed in this study are related to the first megacycle, which is characterized by a tectonic-erosional unconformity above the Neogene basement (electric log, abbr. e-log marker Pt or Tg); its top is the regional e-log marker Rs7. It is generally assumed that the Rs7 marker separates Sarmatian and Pannonian sediments and indicates the period just after the first transtensional and first transpressional events. The youngest elog marker, Rs5, represents the Lower/Upper Pannonian boundary (in Croatian stratigraphic nomenclature) and more generally the early period of the second transtensional event. The lithology of the Lower and Middle Badenian is characterized by coarse and medium-grained sediments, while the Upper Badenian to Lower Pannonian section is dominantly pelitic as a result of flattening of the eroded paleorelief, as well as of reduced amounts of fans and energy. Thickness maps for the stratigraphic intervals Pt/Tg-Rs7 (4.9 Ma) and Rs7-Rs5 (2.2 Ma) were statistically analyzed using a regular grid with individual cells of 500 × 500 m. It is demonstrated that the first transpressional event in this sub-basin continued during the Lower Pannonian, causing a significant decrease of sediment thickness and a large unconformity in the east. Statistics based on histograms and averages confirmed that the first transtension and first transpression can be clearly distinguished by the presented methodology.
