The past five centuries of the Idrija Mercury Mine’s operation have had consequences on the environment, which have directly influenced the deformations developing in the wider exploration area. During the many years of mercury ore exploitation, the cross-stope mining method with backfilling from bottom to top was used. This has strongly transformed the stress-strain field in the surrounding rocks and caused long-term deformation processes that are still in progress. This is because the deformations have a small time gradient and thus bigger breaks or faster sliding terrain above old mine workings are not expected. The surface movements are bigger in the area built of Permian-Carboniferous, low-bearing-capacity rocks, which in the past was destroyed by major tectonic movements in the rock structure. Mine closure works, which included grouting and hardening of destroyed underground areas, as well as filling parts of the mine and backfilling empty spaces (i.e., mine roadways, blind shafts), are finished. The efficiency of mine shutdown works is constantly being verified by means of geotechnical and other measurements and observations, and will continue in the future., Jakob Likar., and Obsahuje bibliografii
The research is focused on the feasibility analysis of a numerical model describing the field of strains generated by mining-induced subsidence caused by a deep underground coal extraction, which may contribute to the formation of Earth fissures. The finite elements method and Knothe’s theory were used in the research. The geomechanical modeling was applied for defining zones of strains and maximum horizontal deformations of the terrain. Knothe’s theory was employed for defining boundary conditions of the geomechanical model. The parameters of the empirical and geomechanical models were scaled out on the basis of geodetic surveys in the mining area. The results of geomechanical modeling were compared with the geodetic surveys to select the best model. The presented research confirmed high congruence between the results of modeling with the finite elements method and observations of vertical movements on the surface. The results of modeling also confirmed the assumed highest stress in areas where earth fissures were observed. The proposed solution may be a new research tool applicable to areas where earth fissures potentially occur. and Malinowska Agnieszka A., Misa Rafał, Tajduś Krzysztof.
We studied the geophysical, physical, and geomechanical parameters of the Podlesí granites in the western part of the Krušné hory Mts., near the village of Potůčky. The granites represent a fractionated intrusion within the Nejdecký Massif. In total, the studied borehole is about 300 m deep. The samples were collected at depths of between 35 and 105 metres. Seismic P-wave and S-wave velocities were measured using ultrasonic scanning. The samples were water-saturated, unsaturated, and dried. The ultrasonic scanning system consisted of four piezoelectric sensors and a digital oscilloscope recorder. The wave frequency was 1 MHz. P-wave velocities range from 4400 m.s-1 to 6500 m.s-1 while S-wave velocities range from 2800 m.s-1 to 3800 m.s-1. These data were used to calculate dynamic Young’s modulus, dynamic shear modulus, and Poisson’s ratio. The deformational characteristics of the rock were specified from experimental loading of the sample with uniaxial strain. The shear and longitudinal deformation of each sample was measured using a resistive strain gauge fixed directly on the sample. Intermittent loading of the samples proceeded using a uniform gradient of axial stress of 1 MPa.s-1. The samples were subjected to five separate loads. During the tests, following parameters were recorded: stress, longitudinal deformation, and shear deformation. These data were used to calculate static Young’s and shear modulus, and Poisson’s ratio., Lucie Nováková, Karel Sosna, Milan Brož, Jan Najser and Petr Novák., and Obsahuje bibliografii
The deformation measurements are performed for the purpose of obtaining information concerning ground movement and objects on the ground within given time intervals. For the purpose of improving conventional models of deformation analysis (CDA) it is desirable to use several different methods and also implement alternative proce dures as a further improvement, such as the concept of robust geodetic networks and strain analysis, aimed at obtaining objective information about the movements. In the present paper, in addition to the CDA methods, we also analyze the robust methods in deformation detecting and the method of the strain analysis based on elasticity theory as a supplement to the conventional geometric deformation methods (CDA). The mentioned methods are applied and analysed for the case of a test example of Fruška Gora in Serbia, for which there exist geological and geophysical studies of recent tectonic movements. The measuring results for two measuring epochs concern the GNSS vectors measured by applying the fast static method within closed polygons over a ten-year interval, where only the horizontal movement component is analysed. The efficiency of the applied CDA and robust methods is measured by applying a mean success rate (MSR) by applying Monte Carlo simulations in order to investigate the efficiency of a given methods for a given control network., Zoran Sušić, Mehmed Batilović, Toša Ninkov, Vladimir Bulatović, Ivan Aleksić and Gojko Nikolić., and Obsahuje bibliografické odkazy
To investigate the geodynamic pattern of the Bohemian Massif in Central Europe, the GEONAS network of permanent GNSS stations was established. It now consists of 18 stations, recorded both the NAVSTAR and GLONASS positional signals; they are located along the tectonic zones of the Massif in order to monitor any movement activities. Yet other stations are still planned to be built, and some recent stations are to be moved within these active areas to increase their local distribution density. The GNSS data are processed by the use of Bernese GPS software 5.0. The time series of station positions give fundamental information for both regional and local geodynamic studies. The GEONAS network covers an area of 400 by 220 km, and it allows the effects of dynamic processes going on inside the Earth’s crust, as well as the upper lithosphere to be monitored. A few examples of geodynamic interpretations are presented here., Vladimír Schenk, Zdeňka Schenková, Milada Cajthamlová and Zdeněk Fučík., and Obsahuje bibliografii
The aim of presented research was to rec ognize a fine geological structure of post-glacial sedimentary forms. The survey was conducted in the South Pomeranian Lake District (north - western Poland) in the vicinity of Pile Lake and Strzeszyn Lake. The geoelectrical equipment Terrameter SAS 4000 (ABEM) with LUND Imaging System was used for the measurements of apparent resistivity of rock mass. The resistivity imaging was carried out im plementing Schlumberger S-protocol with 41 electrodes. Research was done along profiles crossing a border between two sedimentary forms. It allowed to recognize and compare the layered structures of the different post - glacial deposits down to 70 meters be low the surface. The data were interpreted on the base of two-dimensional inversion methods. Results were corre lated and compared with geological dat a accessible in the literature concerning of the research area. Geophysical prospecting gave good results and allowed to recognize a fine geological structure of the deposits., Adam F. Idziak and Anna Wysowska-Świebodzińska., and Obsahuje bibliografické odkazy
Since 2002, the US-German GRACE (Gravity Recovery and Climate Experiment) mission has been providing a precise survey of the Earth's time-variable gravity field, with unprecedented temporal and spatial sampling. GRACE time-variable gravity fields provide a means of measuring the temporal and spatial variations of mass redistribution within the Earth system. The GRACE mission has started a new era in studying a series of geophysical problems ranging from deep Earth structure to tracking mass redistribution on and near the surface of the Earth. Time variability of the gravity field presented here is based on the transformation of “monthly gravity field models” to the geoid. We show the changes caused by the global water cycle and land hydrology., Jan Kostelecký, Aleš Bezděk and Jaroslav Klokočník., and Obsahuje bibliografii
a1_The aim of this paper is to present the strategy of determination of the reference solution for the ASG-EUPOS (Active Geodetic Network - European Position Determination System) coordinate monitoring system. ASG-EUPOS is a network of permanent GNSS (Global Navigation Satellite System) stations controlled by the Polish Head Office of Geodesy and Cartography (HOGC), which main role is to realize the ETRS89 (European Terrestrial Reference System) in the territory of Poland. The Centre of Applied Geomatics (CAG) of the Military University of Technology (MUT) performs a control processing of the network and it is the leader of the ASG+ (the supporting modules for ASG-EUPOS system real-time services) project within which the coordinate monitoring system was developed. The coordinate monitoring is aimed to assess the actual performance of the GNSS stations and the reliability of the system and its services. The Polish realization of the ETRS89 is also controlled, where the deviation of the actual coordinates from the reference values are monitored. Furthermore, the monitoring enables the analysis of factors that degrade the individual GNSS stations and assess the solution stability which has impact on the quality of the determined geodynamic parameters. The reference solutions (coordinates and their changes over time) were determined according to the recommendations of the IAG sub-commission for the European Reference Frame concerning densification of EUREF. The paper presents the determination of the reference cumulative solution and the results of the processing of a few years long series of GNSS observations. The analysis are performed by the Bernese 5.0 and CATREF software. The results consists of daily and subdaily ASG-EUPOS reference solutions. They are also considered as input data for geodynamic studies to determine the horizontal and vertical velocity fields., a2_Estimation of the individual station velocities is of crucial importance for the ETRF (European Terrestrial Reference Frame) reference frame maintenance to assess the compatibility of the current station position with its catalogue (reference) value and apply coordinate correction if necessary., Karolina Szafranek, Janusz Bogusz and Mariusz Figurski., and Obsahuje bibliografii
A refined triple-frequency cycle slip detection and repair algorithm for GPS/BDS undifferenced observables under high ionospheric disturbances is proposed. In this method, three linearindependent optimal observables combinations for GPS/BDS are selected. The residual ionospheric delay estimated from a "calculation-prediction mechanism", namely flexibly determine whether to calculate delay by observables themselves or to predict delay by a feedforward neural network (FNN), is used to compensate for the detection values. Additionally, we devise an adaptive detection threshold based on actual noise level to detect the cycle slip, and adopt the modified least-square decorrelation adjustment (MLAMBDA) to fix integer cycle slip. The performance of the proposed algorithm was tested with observables at 30 s sampling rate in a 2-day geomagnetic storm period. Results showed that the proposed algorithm can detect and repair all kinds of cycle slips as small as one cycle in the case of high ionospheric disturbances. No false repairs are generated despite the occurrence of very few misjudgments., Nijia Qian, Jingxiang Gao, Zengke Li, Fangchao Li and Chen Pan., and Obsahuje bibliografii
The Geodynamic Network Sudety was joined to the Czech Gravity Reference Network (CGRN) by two weeks of the relative gravity measurements. The gravity stations of the CGRN were used as the anchor stations. There were used two relative gravimeters LaCoste & Romberg G. The method of measurement, used instruments, mathematical processing, variants of result computations and their accuracy are discussed., Petr Lukavec and Martin Lederer., and Obsahuje bibliografii