In the West Bohemian region, Central Europe, the volcanic activity appeared in late Tertiary, the Miocene. The present intraplate magmatic activity makes itself felt by flows of gaseous and liquid fluids, enhanced geodynamic mobility of geological structures and generation of earthquake swarms. Position data of two permanent Global Navigation Satellite Systems (GNSS) stations located in the region were used to calculate the time variations of the horizontal strain field that were compared with the 3He/4He ratios and earthquake swarm occurrences. The strains and 3He/4He ratios displayed a positive relation supported by the earlier opinions on the dependence of the dynamics of the region on the fluid occurrence. Analysis of these quantities observed in 2006-2007 period indicated when the compressions calmed and the 3He/4He ratios grew then the earthquake events occurred. It presumes the detected variations relate to compressions and extensions in the region. The strain field changes monitored during the 2008 swarm proved the relation found above. The observed connections could be applied in future at selected regions in earthquake forecast procedures., Vladimír Schenk and Zdenka Schenková., and Obsahuje bibliografii
Presently the determination of the velocity field in the global reference frame is possible by using different space techniques and dense terrestrial networks from global to local and regional scales. However, the reliability of such determinations is strongly limited by the restricted number of unmodeled effects. Some of them are periodic (atmospheric or hydrological effects), some instantaneous (natural or man-made seismicity ) or seasons-related (snow cover, freezing). This elaboration deals with the unmodeled effects observed in the ASG-EUPOS (Polish Active Geodetic Network) time series. The whole network consists of over 130 permanent GNSS sites with different levels of stability. The paper presents the analysis of 3-year’s time-series of geodetic coordinates (in the topocentric projection) in order to obtain best-possible local velocity field. On the example of the Sudeten region, where 19 sites are located, the possible effects on the decrease in reliability of the velocity field determination are described. Finally the local velocity field in ITRF and ETRF frames are presented., Janusz Bogusz, Mariusz Figurski, Bernard Kontny and Piotr Grzempowski., and Obsahuje bibliografické odkazy
Non-liner inversion of ratio of (relative) P to S waves amplitudes of 3 selected KTB events was performed in Kolář (2007a) to determine moment tensors (MTs). Here further development of the method is presented: (i) re-calibration of the seismograms, (ii) re-interpretation of the S wave maximal amplitudes readings, (iii) a linear inversion of the (re-calibrated) amplitudes including MTs errors determination, and (iv) four methods of transformation of MT errors into errors of their decomposed parts. Generally, the new results confirm previous ones, however remain some open questions about MT errors transformation. New methodology is more accura te and data processing more user-friendly., Petr Kolář., and Obsahuje bibliografické odkazy
Chemical composition and structure of humic acids isolated from Cambisols forming on gneiss and amphibolite were studied. Cambisols differ in pH, cation exchange ca pacity, mineralogy composition, organic carbon input, plant residue and type of management. 13 C NMR and FTIR spectroscopy were used to show the main differences in humic substances quality. Humic acids isolated from soils developed on gneiss and amphibolite had wide variety of functional groups and different content of aromatic and aliphatic groups. Humic acids (HA) in arable soils contained more aromatic compounds and carbon in their molecule to compare with HA isolated from grassland. Forming of higher stability aggregates was connected with higher content of aliphatic groups in HA isolated from the grassland. Generally, humic acids in Cambisols represent young humic acids, with lower carbon content and high tendency to oxidation pr ocesses. Their chemical activity was mainly influenced by chemical composition and functional groups content., Ľubica Pospíšilová, Anna Žigová, Martin Šťastný and Tibor Liptaj., and Obsahuje bibliografické odkazy
The two stage co-pyrolysis method for obtaining of hydrogen is described. In the course of the heating of the mixture of bituminous coal with polyisoprene and styrene-butadiene polymers (co-pyrolysis), a considerable amount of hydrogen and hydrocarbons is released in dependence on the process conditions. The experiments proved that the amount of hydrogen increased already with slightly increased heating rate (5 K min-1 ) in comparison with the amount obtained at a common heating rate (3 K min-1) and, further, with the addition of the second (cracking) stage for further thermal splitting of release d hydrocarbons into hydrogen (and carbon), preferably at a temperature of 1200 ºC., Pavel Straka and Vlastimil Kříž., and Obsahuje bibliografické odkazy
Four precise leveling campaigns has been carried out in Poland, and for several years there is a functioning system of permanent GNSS stations determining the height of network points. On the basis of these data, several variants of vertical crustal movements models have been developed (Wyrzykowski, 1987; Kowalczyk, 2005; Kontny and Bogusz, 2012). In order to develop a kinematic model of vertical crustal movements, one of the possibilities is an adjustment of the network formed simultaneously with the leveling data and GNSS stations data. The main problem is a need to identify fiducial points between the datasets. This problem can be solved by creation of coherent database containing attributes of both types of data and automatization of the joint point identification process. The article shows the results of such identification process, depending on the amount of data, on the example of the area of Poland. and Bednarczyk Michal, Kowalczyk Kamil, Kowalczyk Anna.
The aim of this contribution is a detection of geodynamic effects at a very distant geodynamic station GOPE in the middle of Europe (Czech Republic). Strong earthquake, followed by strong indirect effect (tsunami), with the parameters (26.12.2004, 00:58:53.4 UTC, mag. 9.0, latitude 3.295N, longitude 95.982E, depth 30 km) was analysed from the records of tidal gravimeter (ASK No.228) with respect to free oscillations of the Earth (spheroidal component), by spectral analysis. This analysis detected significant vertical component of GOPE position in relatively long time interval (several hours) after the beginning of the earthquake. To verify the geodynamic tendencies of the GOPE station movements the GPS observations were analysed at the same time interval. We had data with 1s sampling interval at our disposal. For analysis we used PPP (Precise Point Positioning) method which produces absolute values of the coordinates in the ITRF 2000 system. Possible correlations between the results of both ways have been searched. We concentrated consequently to the determination of mean displacements and on the attempt of detection of some amplitudes of following free oscillations of the Earth. Mean change of position of the station GOPE during and after the earthquake, detected from the results of GPS observations is about 1.5 cm in horizontal and height components. Amplitude magnitudes for frequencies of the free oscillations of the Earth, which were analysed either from gravimetric data or from the GPS data, are equal in order. The study of free oscillations of the Earth by application of GPS is completely new. Studying of free oscillations is usualy accomplished by data from seismometers, tiltmeters or superconducting gravimeters., Petr Lukavec, Jan Kostelecký, Antonín Zeman, Jakub Kostelecký, Jan Kouba and Vojtěch Palinkáš., and Obsahuje bibliografii
Four space geodesy techniques, namely VLBI, GPS, SLR and Doris, produce Earth orientation parameters (EOP) and station coordinates independently of each other. A method to combine them in a non-rigorous way (as described elsewhere) was modified by implementing Vondrak’s smoothing. It replaces a simple constraint to tie EOP at adjacent epochs by a more general expression defining smoothness of the resulting curves. This gives the method better stability of derived EOP. The new method was tested on GPS, VLBI and SLR data covering a one-year interval. The results were compared with the results of the original method and with the IERS c04 solution. The former indicates the effect of modification while the latter shows differences of this particular solution from the official IERS series, Vojtěch Štefka and Ivan Pešek., and Obsahuje bibliografické odkazy
Three different metakaolins processed by a Portuguese factory were studied aiming to assess the influence of chemical and mineralogical composition of metakaolin on mortar characteristics. Mineralogical analysis of both the fine and clay fractions was carried out by X-ray diffraction. Chemical composition (major elements) was analyzed by X-ray fluorescence. Mineralogical composition reveals some significant differences between the studied samples, in both analyzed fractions, metakaolin 2 being richer in kaolinitic minerals. From a chemical point of view, siliceous content is always high (aroun d 60 %) as well as Al2O3 content (around 30 %); once again metakaolin 2 is the one richer in Al2O3 and poorer in sodium and potassium. Metakaolin from the three different batches was incorporated in lime mortars in order to produce a pozzolanic reaction and hence enable them to harden in high relative humidity conditions or, when access to CO2 is limited, as in the case of mortars supporting glazed tiles. Mortars with the same volum etric ratio were tested for flexural and compressive strength at ages of 28 and 90 days, and the module of elasticity was dete rmined. A relation between the mechanical strength achieved by lime mortars with the addition of metakaolin from different batches and metakaolin mineral and chemical composition was assessed. The knowledge of the influence of the metakaolin com position on the strength of the mortars is an important step in improving their performance and extending their application., Ana Luisa Velosa, Fernando Rocha and Rosário Veiga., and Obsahuje bibliografické odkazy