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Start Over Subject Geologie. Meteorologie. Klimatologie

362. Micro-deformation monitoring of active tectonic structures in W Slovenia

Creator:
Gosar, Andrej, Šebela, Stanka, Blahoslav Košťák, and Stemberk, Josef
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, tektonika, geotectonics, Slovinsko, Slovenia, tectonic movements, active tectonics, monitoring, Dinaric fault system, Dinaric fault system, 7, and 551
Language:
English
Description:
Monitoring of tectonic movements along three active faults of Dinaric (NW-SE trending) fault system in W Slovenia using TM 71 extensiometers was set up in 2004. After two and a half years of measurements clear trends of displacement were recorded. The average left-lateral displacement along a crack in the inner fault zone of the Idrija fault in Učja valley was reading 0.38 mm/year. Short term (10 months) rates were even greater and reached the value of 0.54 mm/year. Since the Idrija fault is considered generally to be dextral strike-slipping, the observed left-lateral displacement can be explained by variations in principle stress. Raša fault monitoring site at the foot of Vremščica Mt. established an average reverse uplift of hanging wall (SW) block of 0.24 mm/year and left-lateral displacement of 0.16 mm/year. Short term (9 months) vertical displacements reached the value of 0.53 mm/year. The inclined displacement is in agreement with geological and seismological observations. In the Postojna cave system two instruments were installed at the fault which extends parallely to Predjama fault zone. The average vertical displacement rate at Postojna 1 site was 0.01 mm/year. Both devices recorded similar reaction which can be attributed to 12 July, 2004 (Mw=5.2) earthquake with an epicentre 70 km away from the measuring site. Since there were no other stronger earthquakes in the vicinity and time span of monitoring, no other correlations were established with earthquake activity. The observed displacement rates along all three monitored faults of up to 0.5 mm/year are consistent with the regional deformation rate in W Slovenia established from GPS measurements which is of the order of 2 mm/year., Andrej Gosar, Stanka Šebela, Blahoslav Košťák and Josef Stemberk., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

363. Microstructure of interfacial transition zone between PET fibres and cement paste

Creator:
Machovič, Vladimír, Lapčák, Ladislav, Borecká, Lenka, Miloslav Lhotka, Andertová, Jana, Kopecký, Lubomír, and Mišková, Linda
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, spektroskopie, spectroscopy, fibre reinforced concrete, Raman mapping microspectroscopy, 7, and 551
Language:
English
Description:
Considerable amount of waste in the form of polyethylene terephthalate (PET) bottles could be utilized in the form of dispersed microreinforcement in concrete. PET fibres, however, have poor wettability and adhesion to cement paste, which can be modified by alkaline hydrolysis with sodium hydroxide at elevated temperature. The alkaline treatment was used to increase fibre surface, which was followed by changes in the structure of the interfacial transition zone (ITZ) and interfacial bond between fibre and cementitious matrix. Raman microspectroscopy mapping was employed to study microstructural changes of ITZ within the distance 0 - 250 μm from a PET fibre. The band at 357 cm-1 corresponding to the Ca-O bond vibration in portlandite was used to determine its distribution. For determination of the relative abundance of ettringite, the SO42- stretching vibration at 987 cm-1 was used. The most intensive bands of portlandite and ettringite were found within the distance 0 - 50 μm from an unmodified PET fibre. Besides the elevated concentration of these minerals, abundant pores occur in this region. In the case of alkaline modified PET fibres the ITZ zone was not found., Vladimír Machovič, Ladislav Lapčák, Lenka Borecká, Miloslav Lhotka, Jana Andertová, Lubomír Kopecký and Linda Mišková., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

364. Microstructure of selected metamorphic rock types: application of petrographic image analysis

Creator:
Šachlová, Šárka, Vladimír Schenk, and Zdeňka Schenková
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, metamorfované horniny, mikroskopie, metamorphic rocks, microscopy, texture, structure, kinematic indicators, 7, and 551
Language:
English
Description:
Microscopic techniques, such as polarising microscopy and scanning electron microscopy with energy dispersive spectrometer (SEM/EDS), were used in combination with petrographic image analysis with the aim of a quantitative determination of the mineral composition, rock microstructure, and degree of metamorphism of selected quartz-rich metamorphic rock types. Sampled orthogneiss rock types are mainly composed of feldspar, quartz, biotite, and amphibole. The grains are less isometric, elongated, having smooth boundaries, and showing a weak preferential orientation. The deformation and recrystallization characteristics of quartz indicate high-temperature recrystallization (the grain boundary migration recrystallization mechanism). Schist and phyllite rock types are preferentially very-fine to fine-grained, showing a strong shape preferred orientation. Their sedimentary origin was indicated by the presence of graphite. The deformation and recrystallization characteristics of the quartz indicate low temperature conditions of their metamorphism., Šárka Šachlová, Vladimír Schenk and Zdeňka Schenková., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

367. Mineral composition of the deep sea sediments in three sectors of Western Pacific Ocean

Creator:
Karel Melka, František Fediuk, and Langrová, Anna
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, sedimenty, sediments, Korálové moře, Tichý oceán (západní oblast), West Pacific Ocean, Philippine Sea, Solomon Sea, Coral Sea, electron microprobe analysis, X-ray quantitative diffraction analysis, adiabatic principle, secondary electron images, 7, and 551
Language:
English
Description:
During the International expedition of the research vessel Dmitry Mendeleyev three sectors of the Western Pacific Ocean were studied: Philippine Sea, Solomon Sea and Coral Sea. From these areas also the samples for the orientation were taken in order to do the mineralogical examination with them. Above all, X-ray diffraction technique was used beside the chemical analysis performed by electron microprobe analyzer. Quantitative evaluation of min eral components was carried out applying X-ray diffraction. Standardless technique based on the adiabatic principle enabled th e quantitative determination directly from the X-ray diffraction diagram. Generally, sheet silicates - above all smectite, chlorite, mica (illite) - play the leading role in the mineral composition of collected samples of muds taken from the ocean floor. Besi des, also minerals of terrigenous origin are present: quartz prevailing mostly over feldspars (plagioclase > K-feldspar). Amphiboles and pyroxenes occured, but not everywhere. Carbonate minerals (calcite >> aragonite) were found only in samples from Coral Sea., Karel Melka, Ferry Fediuk and Anna Langrová., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

369. Mineralogy of the clay gouge on Prague fault

Creator:
Hájek, Pavel and Martin Šťastný
Format:
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Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, jílové minerály, ordovik, clay minerals, Ordovician, Prague fault, clay mineralogy, X-ray diffraction, clay gouge, quartzite, cataclasis, 7, and 551
Language:
English
Description:
The research has dealt with mineral composition of the dislocation clays developed on the Prague fault. The Prague fault is a tectonic boundary between underlying clayey slates of Záhořany series and Skalka quartzite. The fault zone is filled with clay or sandy-silt to silty-sand matrix with scattered fragments of the surrounding rocks either slates or quart zite. Quartz, illite, kaolinite, chlorite, sporadic feldspar and gypsum were identified in powdered preparations by X-ray diffraction. The clay fraction of the taken samples is composed of illite, less kaolinite and sporadic chlorite and gypsum., Pavel Hájek and Martin Šťastný., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

370. Modeling of vibration effect within small istances

Creator:
Martin Stolárik
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, metoda konečných prvků, finite element method, technical seismicity, blasting operation, 7, and 551
Language:
English
Description:
The growth in the field of construction of shallow underground structures has been associated with construction of new roads, collectors and other structures. This contribution deals with modeling of distribution pattern of the maximum velocity amplitude (blasting vibration field) on surface basement. This basement will be situated within small distance from source of technical seismicity that is used as a part of technological processes. The model represents seismic effect of blasting operati on in shallow tunnel. Plaxis 2D modeling system and its dynamic module based on finite element method are used for this presentation., Martin Stolárik., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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