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Start Over Subject Geologie. Meteorologie. Klimatologie Subject geodynamika

72. Stability of period and quality factor of free core nutation

Creator:
Jan Vondrák and Cyril Ron
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Subject:
Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, earth orientation, nutation, geophysical excitation, VLBI, 7, and 551
Language:
English
Description:
In our study we find, from the analysis of VLBI observations, small quasi-periodic fluctuations of the period and quality factor of retrograde Free Core Nutation (FCN), ranging mainly between 429.8 to 430.8 days and 17000 to 21000, respectively. To this end, we use resonant effects in several dominant forced nutation terms to calculate the period and quality factor of FCN in running 6-year intervals. We also recently demonstrated that the atmospheric and oceanic excitations are capable of exciting FCN. Both amplitude and phase of the geophysically excited motion are consistent with the values observed by VLBI, in the interval of tens of years. The geophysical excitations are now numerically integrated, using Brzeziński’s broadband Liouville equations, and removed from the observed celestial pole offsets. The remaining part is then used to derive the period and quality factor of FCN in running intervals, and to study the temporal stability of these important Earth parameters. It is demonstrated that the observed quasi-periodic variations of both parameters are probably not caused by these geophysical excitations., Jan Vondrák and Cyril Ron., and Obsahuje bibliografii
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73. Statistical evaluation of the 3D monitoring of displacements of dinaric fault zone in Postojna Cave, Slovenia

Creator:
Šebela, Stanka, Turk, Janez, Janez Mulec, and Stemberk, Josef
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print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, jeskyně, geodynamika, caves, geodynamics, Postojna (Slovinsko), Postojna (Slovenia), micro-tectonic displacements, 3D monitoring of displacements, TM 71 extensometer, statistical evaluation, Postojna Cave, Slovenia, 7, and 551
Language:
English
Description:
The results obtained by four years long TM 71 extensometer monitoring of 3D micro-tectonic displacements of Dinaric Fault Zone on two sites, being 260 m apart in Postojna Cave, were statistically evaluated with different methods (Kolmogorov- Smirnov test, comparison between relative displacement and earthquakes, linear regression, Kruskal-Wallis one-way analysis of variance, histograms and correlation coefficients). Responses to stress changes regarding x, y and z-axes are not the same on two monitoring sites even if we are monitoring the same fault zone. Kolmogorov-Smirnov test for comparing the two curves is applicable only for three axes combination (Postojna 1 z - Postojna 2 z, Postojna 2 y - Postojna 1 z, and Postojna 2 z - Postojna 2 y). Kruskal-Wallis analysis is most representative for z-axes. Some sharp peaks coincide with earthquake occurrences (Krn M=5.2, Cerkno M=4.0, Ilirska Bistrica M=3.9, Brežice M=2.9 and Krško M=3.1). Generally we detect very small tectonic deformations, dextral horizontal movement of 0.05 mm in 4 years for Postojna 1 and extension of 0.03 mm in 4 years for Postojna 2. Discrepancies between two sites can be attributed to complex geological structure and by the fact that studied fault zone is cut by cross-Dinaric fault zone., Stanka Šebela, Janez Turk, Janez Mulec, Blahoslav Košťák and Josef Stemberk., and Obsahuje bibliografii
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74. Study of adhesion of cement mixture and fibres and changes of its tension properties

Creator:
Jiřina Trčková and Řezba, Karel
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Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, fibre cement mixture, pullout test, tension properties, laboratory test, 7, and 551
Language:
English
Description:
To obtain the starting point for theoretical numerical computations the fibre reinforced concrete construction properties, adhesion of cement mixture with steel and polypropylene fibres and changes in its tension properties commensurate with number and weight percentage in the tested specimen were tested under laboratory conditions., Jiřina Trčková and Karel Řezba., and Obsahuje bibliografické odkazy
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75. Study of site effect using mining induced seismic events and ambient noise from Karviná Region

Creator:
Zdeněk Kaláb and Lyubushin, Alexey A.
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Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, mining induced seismic event, ambient noise, spectral ratio, frequency analysis, 7, and 551
Language:
English
Description:
Evaluation of seismic loading in urban areas is not a simple process. The horizontal to vertical spectral ratio method technique has been often used for determination of site effect recently. Results from the re-interpretation of mining induced seismic events from Karviná region in frequency domain using archival databases will be presented in this study material. Also, spectra of continuous records (a bout two days) and evolution of spectra within a moving time window of the length 10 seconds are presented. These continuous records were registered on two places with different geological conditions., Zdeněk Kaláb and Alexey A. Lyubushin., and Obsahuje bibliografické odkazy
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76. Study of the effect of moisture content and bending rate on the fracture toughness of rocks

Creator:
Leona Vavro and Kamil Souček
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Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, fracture toughness, bending rate, tensile strength, 7, and 551
Language:
English
Description:
Generally, rock material failure is controlled by cracks under specific conditions. The study of rock fracture toughness belongs to the current frequent directions of research in the area of rock failure. The present paper describes the effects of parameters influencing the resultant properties of rock materials (bending rate, rock moisture) during fracture toughness measurement of different kinds of rocks (sandstone, marble, granite). The highest fracture toughness values were found in the marble samples. This is probably due to the inner structure of analysed marble, which is composed of only one mineral (calcite) and also has a lower porosity than the used granite. The lowest fracture toughness values were found in the sandstone sample, and reached c. 17-30 % of the measured fracture toughness values of the analysed granite and marble samples. As in the case of the other mechanical properties of rocks (e.g. uniaxial compressive strength) also in the case of higher sandstone (carboniferous) moisture the fracture toughness values decrease and its deformation ability increases. Preparation of samples for fracture toughness tests and performance of these tests are more complicated than in the case of tensile tests (e.g. the Brazilian test) and therefore this contribution presents a comparison between fracture toughness of analysed rocks and tensile strength values. The measured data in this study considering the fracture toughness tests and Brazilian tests were compared with results published by Zhang (2002)., Leona Vavro and Kamil Souček., and Obsahuje bibliografii
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77. The Sudetic Marginal Fault: a young morphophotectonic feature at the NE margin of the Bohemian Massif, Central Europe

Creator:
Badura, Janusz, Zuchiewicz, Witold, Štěpančiková, Petra, Przybylski, Bogusław, Kontny, Bernard, and Cacoń, Stefan
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Type:
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Subject:
Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, Polsko jihozápadní, Čechy severovýchodní (Česko), Poland, Bohemia, Northeastern (Czechia), morphotectonics, digital elevation models, drainage basin parameters, Sude tic Marginal Fault, 7, and 551
Language:
English
Description:
We analysed a nearly 133-km-long portion of the Sudetic Marginal Fault (SMF) in Poland (99.7 km) and the Czech Republic (33.8 km), comprised between Złotoryja in the NW and Jesenik in the SE. The fault trace has been subdivided into fifteen segments showing different orientation (N29°W to N56°W, and even N111°W SE of Złoty Stok), geological setting, length (8.8-22.9 km in Poland and 1.4-7.5 km in the Czech Republic), and height of the fault- and fault-line scarps (5-75 m to 200-360 m). Orientation of the entire fault trace approaches N41° W, and the mountain front sinuosity amounts to 1.051. Individual fault segments bear a flight of two to five tiers of triangular facets, showing differentiated state of preservation and degree of erosional remodelling. The highest triangular facets are confined to Rychlebské (Złote) and Sowie Mts. This tiering points to at least five episodes of uplift of the SMF footwall, starting shortly after 31 Ma, i.e. after basalts of the Sichów Hills area were displaced by the fault, and most probably postdating 7-5 Ma time interval, during which rapid cooling and exhumation of the Sowie Góry Mts. massif took place. Morphometric parameters of 244 small catchment areas of streams that dissect the fault scarp include, i.a. elongation, relief, and average slope of individual catchment areas, together with values of the valley flo or width to valley height ratios. These figures point to moderate tectonic activity of the SMF and allow us to conclude about Quaternary uplift, particularly important in the Sowie and Rychlebské (Złote) segments., Janusz Badura, Witold Zuchiewicz, Petra Štěpančiková, Bogusław Przybylski, Bernard Kontny and Stefan Cacoń., and Obsahuje bibliografické odkazy
Rights:
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78. The Upper Silesian Coal Basin fault zone as a region of high-risk operations

Creator:
Cmiel, Stanisław Roman
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Subject:
Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, Horní Slezsko, Upper Silesia, epigenetic changes of coal, fault zones, strength parameter values of rocks, 7, and 551
Language:
English
Description:
This paper presents the results of investigations on changes of the parameters of coal and surrounding rocks in the fault zones in the Upper Silesia Coal Basin. It has been shown that these zones, in relation to the undisturbed coal seams, reveal a n enrichment with some substances that pose a threat to the natural environment and that they also show a deterioration in the strength parameter values of rocks which threaten the safety of the operation. The greatest threat for the environment constituted sulphur and the ash. In the zone of the fault, it wa s observed that sulphur behaved in two ways. In the first case, the total sulphur and pyritic sulphur increased significantly by 192.3 and 823.5 %, respectively, and a small quantity of sulphate sulphur was found here, whereas in the other case, the total sulphur and pyritic sulphur decreased by 31.6 an d 35.3 %, respectively, and sulp hate sulphur increased considerably and reached up to 600 %. The mean content of ash increased by 171.8 %. The mechanical strenght of the rocks under uniaxial compressive strength in the fault zones decreased by 67 %, the microhardness of coal decreased to zero, and the intensity of cracks in coal grains increased by 359.1 %., Stanisław Roman Cmiel., and Obsahuje bibliografické odkazy
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79. The use of land information system in geomorphostructural analysis on the example of Inowrocław

Creator:
Szczerbowski, Zbigniew
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Type:
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Subject:
Geologie. Meteorologie. Klimatologie, geodynamika, nivelace, hornictví, geodynamics, leveling, mining, salt geology, subsidence, salt domes, 7, and 551
Language:
English
Description:
The importance of GIS detailed data for geomorphostructural study is discussed. This paper is a case study in the area of Inowrocław (central Poland). This small area is a place being a concentration of geological processes and its relief depicted by a number of height points (with determined elevations of satisfying accuracy required in the analysis) demonstrates their effects. The invented approach is based on a numerical analysis of actual and theoretical relief surfaces. Considering the area type this study involves a high resolution model of the relief. There are specified examples of correlation between morphological features and tectonic structures. The presented results prove a role of structural elements (faults) in development of geomorphostructural features and a tectonic mobility as a significant factor forming the area relief., Zbigniew Szczerbowski., and Obsahuje bibliografii
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80. The use of sar interferometry for the study of landslips in the Polish Flysch Carpathians

Creator:
Mirek, Katarzyna
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Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, satellite remote sensing, InSAR, landslips, 7, and 551
Language:
English
Description:
The article discusses techniques for interpreting satellite images, which are capable of detecting and monitoring landslip zones, and presents a research plan for the study of landslips with the use of satellite interferometry. The exceptionally longlasting and heavy rainfall that occurred in 1997 initiated more than 20,000 landslips within the Polish Carpathians. These landslips continue to pose a threat. Some of them move almost imperceptibly - slowly but continually - yet long-lasting periods of heavy rainfall can lead to catastrophe. The price can be human lives, as well as losses into the millions connected with the devastation of technical infrastructures and entire housing estates. The sheer number of landslips that occur in the Polish Carpathians makes the traditional ways of researching them insufficient. Satellite remote sensing allows capturing a large area of interest on a single photo. Many various satellites photograph the surface of the Earth using different techniques, allowing for the selection of the best-suited image type for a given application. Synthetic Aperture Radar (SAR) images are utilized in landslip studies. The images may be interpreted using the InSAR and/or PSInSAR techniques. Both methods are capable of detecting landslip zones and monitoring them in order to assess the risk of a sudden landslide. Information of this type is significant to local authorities when planning the activities necessary to protect the safety of inhabitants and the local technical infrastructure., Katarzyna Mirek., and Obsahuje bibliografii
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