The astrogeodetic method of detailed geoid determination need astronomical observations of longitude and latitude. Together with GPS observations it may be used to vertical deflections determination. In the article the portable system for automatic determination of astrogeodetic vertical deflection components developed at AGH University of Science and Technology is described. The design, main error sources, and preliminary results of the test measurements are presented., Jacek Kudrys., and Obsahuje bibliografii
The known vertical deflection values can be utilised to increase geoid’s accuracy. One of the methods of vertical deflection components (ξ, η) determination is to compare astronomic and geodetic coordinates. Presently it is easy possible to obtain geodetic coordinates with high accuracy from GPS observation. In the article the methods of astronomical CCD observation with aid of two different optical systems are discussed. Project realisation is in preliminary stage and there are no results available yet., Jacek Kudrys., and Obsahuje bibliografické odkazy
This paper discusses the quality of slant wet delays (SWD) computed from GPS measurements. The SWDs are generally used as input data for GPS tomography, which allows the three-dimensional reconstruction of water vapour distribution in the atmosphere. The research presented is based on a comparison of slant wet delays acquired by different strategies based on double-differenced Global Positioning System (GPS) data. The GPS-derived SWDs were compared with those directly measured by a water vapour radiometer (W VR). The best results from the applied G PS strategies were achieved by a simple mapping of GPS-derived zenith total delays into SWD without adding horizontal gradients or post-fit residuals., Michal Kačmařík, Jan Douša and Jan Zapletal., and Obsahuje bibliografické odkazy
This paper presents results from the exam ination of flood embankments by means of three geophysical methods: GPR, mutual impedance of loop antennas measurements and D.C. resistivity method. In order to increase measuring accuracy, the mutual impedance measuring system works at a high frequency. Parameters of mutual impedance measuring system were presented. A method of mutual im pedance measurement results was described. Flood embankments examination results showed that the simultaneous use of few geophysical methods increases accuracy of inhomogeneities detection in near-surface structure of the ground., Remigiusz Mydlikowski, Grzegorz Beziuk and Adam Szynkiewicz., and Obsahuje bibliografické odkazy
Using synthetic data we study the possibility of determining 1-D velocity models of the upper crust from P- and S-wave arrival times in the case of a narrow depth interval of seismic sources and sparse distribution of stations. The test is tailored to a similar real situation in one subregion of the western part of the Corinth Gulf, Greece. Two kinds of models are studied: (i) models composed of layers with constant velocity gradients, and (ii) models composed of homogeneous layers. To derive the structural models from arrival times, the Neighbourhood Algorithm of Sambridge (1999) is used, combined with the grid search for source locations. Weighted P- and S-wave arrival time residuals are used as the misfit function. Accurate and perturbed synthetic arrival times are used. The velocities at medium depths, with a fast velocity increase, are well determined in both models for the accurate data. However, the determination of velocity is less certain in the uppermost 5 km for the gradient model, and in the deepest layer for the model composed of homogeneous layers for the perturbed data. The presence or absence of hypocentres in the uppermost or in the second layer influences notably the obtained velocity in these layers in both models., Jaromír Janský, Vladimír Plicka and Oldřich Novotný., and Obsahuje bibliografii
Permo-Carboniferous and Cretaceous sediments cover the main tectonostratigraphic units of the crystalline basement in NE Bohemia. Within the activities of “Research Centre for Advanced remedial Technologies and Processes” the Czech Geological Survey revises the boreholes and geophysical investigations in the Bohemian Cretaceous Basin and adjacent areas. One part of the research is a compilation of pre-Cretaceous relief of the basement including the crystalline basement and Permo-Carboniferous relief. The digital elevation model uses all boreholes from the Czech Geological Survey-Geofond database, previous geophysical interpretation and the recent surface of the individual geological units defined from detailed geological mapping. The final model reflects well the evolution and recent position of several tectonic blocks and subsequent reprocessing of the information about basement rocks enables compilation of the ´solid´ geological map., Zuzana Skácelová, Bedřich Mlčoch and Zuzana Tasáryová., and Obsahuje bibliografii
a1_In cooperation with AIUB (Astronomical Institute University of Berne), GOP (Geodetic Observatory Pecný) and IGN (Institut Géographique National), DORIS data analysis capabilities were implemented into the development version 5.0 of the Bernese GPS Software. The DORIS observables are reformulated that they are similar to GNSS carrier phase observations as much as possible allowing the use of the same observation models and algorithms as for GNSS carrier phase data analysis with only minor modifications. Evolution of DORIS data analysis using Bernese GPS Software is presented from the pilot campaign (September 2004) to the automatic processing of multi-year data time-series. The station and pole coordinates were estimated within the free-network approach and the long time-series of weekly estimated parameters are presented (1993.0- 2009.0) and analyzed. The RMS of the estimated polar coordinates significantly decreased after 2002, when the second generation of DORIS satellites was launched. A significant improvement has been achieved by processing the data from the new satellites (SPOT-5 and Envisat) launched in 2002. The RMS in 2003-2009.0 shows the decreasing trend and reached values close to 0.4 mas in both coordinates (2007-2008). Behavior of the terrestrial reference frame scale was quite stable with a few exceptions. Analysis of the major scale shift at the end of 2004 revealed the SPOT-5 and Envisat satellites as the source of the problem. On the other hand, the termination of the TOPEX/Poseidon DORIS data processing at the end of 2004 did not influence significantly the overall scale level. Another goal of the paper is a detail analysis of relations between the value of the observation residuals and the length of the observation time-interval. A simple empirical model considering the observation noise as a sum of the constant and time-dependent terms is applied and discussed., a2_A significant DORIS-GNSS ZTD bias as well as station height bias have been detected in the case of the SPOT-5 data for South America stations Santiago, Cachoiera Paulista, and Arequipa. These stations are located in the area of the South Atlantic Anomaly (SAA)., Petr Štěpánek, Vratislav Filler, Urs Hugentobler and Jan Douša., and Obsahuje bibliografii
The long water-tube tiltmeter observations of the plumb line variations were begun about four years ago. Since 2001, twice, the instrument registered strong plumb line variations associated with earthquake. Earthquake in September 2003 made opportunity for verification of hydrodynamic system of tiltmeter. We obtained in observations large number of cycle-slip effects, which made impossible correct interpretation of data during main phase of phenomenon. Results of tests of dumping system of water waving helped us to introduce some improvements in hydrodynamic system of instrument. Catastrophic earthquake with magnitude 9.1 which took place in the area of Indian Ocean on 26th December 2004 generated phenomenon of the Earth free oscillations associated with anomalous plumb line variations of the order of single milliseconds of arc (mas). The effects of surface waves passing associated with Earth free oscillations were registered by the tiltmeter as series of anomalous plumb line variations. Surface waves produced several milliseconds of arc amplitude of plumb line variations. Results of observations showed that low-pass filters considerably reduce contribution of short-period effects and effectively protect hydrodynamic system of instrument against resonance. Nevertheless during first two hours of phenomenon cycle-slip effects occurred several times. Plot of plumb line variations in space from 26th December 2004 showed us large complication of tilt signals as well as dominated role of tidal signal. Spectral analysis of the time series of the plumb line variations obtained with help of the long water-tube tiltmeter on 26 December 2004 appeared existing fundamental modes (n = 0) in the Earth free oscillations didn’t exceed 0.2 mas., Marek Kaczorowski., and Obsahuje bibliografii
Using of shaped conical borehole bottom to determination of the stress tensor changes induced by changing of geomechanical situation is described in this paper. The measured strain changes on gauge probe are caused not only by the stress changes evocateg by progress of long wall. The some deformation started imediatelly after instalation when the long wal didn't move. In paper are discussed the eventu alities of this phenomenon too., Lubomír Staš, Kamil Souček and Jaromír Knejzlík., and Obsahuje bibliografické odkazy