Search Results

You are looking at 1 - 10 of 119 items for :

  • methodology x
Clear All
Open access

Lenka Kubišová

Abstract

We review the recent archaeomagnetic studies carried out on the territory of Slovakia, focusing on the comparison of methodological approaches, discussing pros and cons of the individual applied methods from the perspective of our experience. The most widely used methods for the determination of intensity and direction of the archaeomegnetic field by demagnetisation of the sample material are the alternating field (AF) demagnetisation and the Thellier double heating method. These methods are used not only for archaeomagnetic studies but also help to solve some geological problems. The two methods were applied to samples collected recently at several sites of Slovakia, where archaeological prospection invoked by earthwork or reconstruction work of developing projects demanded archaeomagnetic dating. Then we discuss advantages and weaknesses of the investigated methods from different perspectives based on several examples and our recent experience.

Open access

Lotta Blaškovičová, Oliver Horvát, Kamila Hlavčová, Silvia Kohnová and Ján Szolgay

Methodology for post-event analysis of flash floods - Svacenický Creek case study

In this paper a methodology for a post-event analysis of a flash flood and estimation of the flood peak and volume are developed and tested. The selected flash flood occurred on the 6th of June, 2009 in the Svacenický Creek Basin. To understand rainfall-runoff processes during this extreme flash flood, the runoff response was simulated using the spatially-distributed hydrological model KLEM (Kinematic Local Excess Model). The distributed hydrological model is based on the availability of raster information about the landscape's topography, soil and vegetation properties and radar rainfall data. In the model, the SCS-Curve Number procedure is applied to a grid for the spatially-distributed representation of the runoff-generating processes. A description of the drainage system's response is used to represent the runoff's routing. The simulated values achieved by the KLEM model were comparable with the maximum peak estimated on the basis of the post-event surveying. The consistency of the estimated and simulated values from the KLEM model was evident both in time and space, and the methodology has shown its practical applicability.

Open access

Hana Středová and Filip Chuchma

precipitation and temperature variation in Central Europe in in the years 1881-1980 (Tendencje zmian temperatury i opadów w Europie sródkowej w stuleciu 1881-1980). Acta universitatis Nicolai Copernici, Geografia, XXII, 73, 22-43 (in Polish). Mašát К. et al., 1974: Methodology for defining and mapping of valuated soil ecologi- cal units (Metodika vymezování a mapování bonitovaných půdně ekologických jed- notek), 2nd edition, CAZ - Institute for Agricultural Soil Survey, Praha, 113 p. (in Czech). Mužíková В., Vlček V., Středa T., 2011

Open access

Filip Chuchma and Hana Středová

Development, 26 , 441–449. Bielek P.,Čurlík J., Fulajtár E., Houšková B., Ilavská B., Kobza J., 2005: Soil Survey and Managing of Soil Data in Slovakia. European Soil Bureau, Research report No. 9, 317–329. Kohut M., Chuchma F., Hora P., 2012: Selected agroclimatic characteristics of climatic regions of the Czech Republic. Contributions to Geophysics and Geodesy, 42 , 3, 269–281. Mašát K. et al., 1974: Methodology for defining and mapping of Estimated Pedologic-Ecological Units (Metodika vymezování a mapování bonitovaných půdně ekologických jednotek). 2

Open access

Dimitrios Ampatzidis and Stavros Melachroinos

Abstract

In the present paper we are dealing with the problem of the connection of two local geodetic datums in which the classical transformation procedures fail to give sufficient solution. Thereafter, we additionally implemented Least Squares Collocation in order to model the remaining residuals of the initial transformation. We tested this methodology in an area located in Northern Greece and we found significant improvement of the transformation results. The implementation of Least Squares Collocation refines the statistical behaviour of the inconsistencies regarding their extreme values (minimum and maximum) from almost 70 to 23 cm, while the standard deviation is reduced from the level of 27 to 10 cm.

Open access

Jana Dérerová, Miroslav Bielik, Mariana Pašiaková, Igor Kohút and Petra Hlavńová

Abstract

The temperature model of the lithosphere along transect II passing through the Western Carpathians and the Pannonian Basin has been calculated using 2D integrated geophysical modelling methodology. Based on the extrapolation of failure criteria, lithology and calculated temperature distribution, we derived the rheology model of the lithosphere in the area. Our results indicate a decrease of the lithospheric strength from the European platform and the Western Carpathians towards the Pannonian Basin. The largest strength can be observed within the upper crust which suggests rigid deformation in this part of the lithosphere. In the lithospheric mantle, strength almost disappears which allows us to assume that the ductile deformation dominates in this part of the lithosphere

Open access

Viliam Šimor, Kamila Hlavčová, Silvia Kohnová and Ján Szolgay

Abstract

This article presents an application of Artificial Neural Networks (ANNs) and multiple regression models for estimating mean annual maximum discharge (index flood) at ungauged sites. Both approaches were tested for 145 small basins in Slovakia in areas ranging from 20 to 300 km2. Using the objective clustering method, the catchments were divided into ten homogeneous pooling groups; for each pooling group, mutually independent predictors (catchment characteristics) were selected for both models. The neural network was applied as a simple multilayer perceptron with one hidden layer and with a back propagation learning algorithm. Hyperbolic tangents were used as an activation function in the hidden layer. Estimating index floods by the multiple regression models were based on deriving relationships between the index floods and catchment predictors. The efficiencies of both approaches were tested by the Nash-Sutcliffe and a correlation coefficients. The results showed the comparative applicability of both models with slightly better results for the index floods achieved using the ANNs methodology.

Open access

Bronislava Spáčilová, Tomáš Středa and Pavlína Thonnová

Abstract

Wind erosion risk strongly depends on soil surface conditions. Aridity or dryness of the climate in the Czech Republic is a typical property for Southern Moravia and Central Bohemia. The study aims to map and assess qualitatively the areas vulnerable to wind erosion using available data and intelligible methodology. The evaluation is based on the number of days when at least once a day dry condition of bare soil surface was recorded. Daily data of soil surface state from 70 climatological stations to 500 m altitude from 1981 to 2010 are used. First, soil conditions from 1st March to 30th April and from 1st September to 31st October were evaluated. Evaluation of erosion risk in May is presented separately in the second phase, because only thermophilous crops (late-sowing crops) can be affected in that time. The results show that mainly in the South and Southeast Moravia, there are areas where up to 60 days with dry soil surface in the spring and autumn occurred. Occurrence of such conditions may represent potential risk of wind erosion for arable soils and therefore potential risk for sown crops and loss of fertile soil surface which is irreplaceable for agricultural activities. The results are applicable for preparation of a concept of wind erosion control measures in the threatened regions.

Open access

Ladislav Brimich and Igor Kohút

Abstract

Thermo-elastic strains and stresses play a considerable role in the stress state of the lithosphere and its dynamics, especially at pronounced positive geothermal anomalies. Topography has a significant effect on ground deformation. Two methods for including the topographic effects in the thermo-viscoelastic model are described. First we use an approximate methodology which assumes that the main effect of topography is due to the distance from the source to the free surface and permits to have an analytical solution very attractive for solving the inverse problem. A numerical solution (for 2D plain strain case) is also computed using finite element method (FEM). The numerical method allows to include the local shape of the topography in the modeling. In the numerical model the buried magmatic body is represented by a finite volume thermal source. The temperature distribution is computed by the higher-degree FEM. For analytical as well as numerical model solution only the forces of thermal origin are considered. The results show that for the volcanic areas with prominent topography, its effect on the perturbation of the thermo-viscoelastic solution (deformation and total gravity anomaly) can be quite significant. In consequence, neglecting the topography could give erroneous results in the estimated source parameters.

Open access

Ladislav Brimich, María Charco, Igor Kohút and José Fernández

3D analytical and numerical modelling of the regional topography influence on the surface deformation due to underground heat source

Thermo-elastic strains and stresses play a considerable role in the stress state of the lithosphere and its dynamics, especially at pronounced positive geothermal anomalies. Topography has a significant effect on ground deformation. In this paper we describe two methods for including the topographic effects in the thermo-viscoelastic model. First we use an approximate methodology which assumes that the main effect of the topography is due to distance from the source to the free surface and permits to have an analytical solution very attractive for solving the inverse problem. A numerical solution using Finite Element Method (FEM) is also computed. The numerical method allows to include the local shape of the topography in the modelling. In the numerical model the buried magmatic body is represented by a finite volume thermal source. The temperature distribution is computed by the higher-degree FEM. For analytical as well as numerical model solution only the forces of thermal origin are considered. The comparison of the results obtained using both analytical and numerical techniques shows the qualitative agreement of the vertical displacements. In the numerical values small differences were obtained. The results show that for the volcanic areas with an important relief the perturbation of the thermo-viscoelastic solution (deformation and total gravity anomaly) due to the topography can be quite significant. In consequence, neglecting topography could give erroneous results in the estimated source parameters.