Use of the UNB_TopoDens model for local modelling of chosen gravity field parameters in the Western Carpathians

The latest, global density model of topographical masses (UNB TopoDms model) was used to determine complete Bouguer anomalies and the differences between geoid undulations and height anomalies in an area of the Western Carpathians, within the Polish-Slovak-Czech border region. The ranges of the calculated values are between approximately -74 and +23 mGal for Bouguer anomalies and -10 and +5 cm for differences between geoid and quasigeoid heights. Calculations were also performed for constant densities of topographical masses (2200, 2500 and 2670 kg/m(3)). The results show significant differences due to the various densities adopted for the calculations. For example, differences between the version using densities from the UNB TopoDens model and the version using a constant density of 2670 kg/m(3) ranged between -3.4 mGal and +37.5 mGal, for Bouguer anomalies, and between -0.5 cm and +7.4 cm for differences between geoid undulation and height anomalies. It has also been shown that, for high mountain areas, differences between geoid and quasigeoid height should be determined on the basis of exact formula (not on the basis of Bouguer anomalies).Web of Science17111811

Investigations Regarding Bear Cave Massif (Lower Silesia) Long-Term Stability

Bear Cave under Mt ¦nie¿nik is located near the Lower Sile­sian Village of Kletno in a wider tectonic fault zone of Sudeten, Klodzko Valley, South Poland. Stability requirements along the visitor’s path in the cave called for permanent checks of pos­sible rock movements in the massif, while mining operations in the neighbouring marble quarry represented major threat to cave stability. Precise levelling network for vertical movements in the cave and its vicinity was established about 20 years ago. Outside the cave in the Kle¶nica River valley levelling traverses were crossing tectonic faults. Periodical measurements have been repeated since 1984. In the cave two fault zones of major risk have been checked also with TM-71 crack gauges and re­cords have been taken with a month frequency. These two were the tectonic crack zones of the Water Corridor and the main fault structure of the cave found in the Cascade Alley. Fourteen years ago after finding that quarry blasts induced increased movements in the cave, quarry operations were stopped. Re­cently, gradual subsidence of some levelling bench-marks was observed, as well as some periods of increased micro-displace­ments on the tectonic crack zones. Such observations are dis­cussed

Post-alpine tectonics of the Upper Nysa Kłodzka Graben : a reply

The paper aims to answer the critical remarks presented by Don and Wojewoda (in this issue) related to our papers published in Acta Montana (Badura et al., 2002, Badura et al., 2003). Answering those we have noticed that the terms brachysyncline and brachyanticline are improper with regard to the young Alpine rebuilding of the Upper Nysa Kłodzka Graben. In this paper we present the basic reasons for our hypothesis of young tectonic movements in the studied area more widely. Our morphotectonic analyses are based on the digital elevation models (DEM) and the electroresistance survey of the researched area located near Kamienna and north of Długopole Zdrój. The results of our research show that despite of the long history of the geological studies - longer than 100 years, the region is still a very challenging research area. In this paper we point out that application of the DEM and electroresistivity methods gives the new important results. Those should definitely be taken into consideration together with palaeontological research and geological mapping. We really wonder that the authors of the critical paper unequivocally negate the results of our studies and suggest that the continuation of such research and geodetic survey in the area is aimless

Determination of the selected gravity field functionals by the GGI method: A case study of the Western Carpathians area

In this paper, some features of the local disturbing potential model developed by the GGI method (based on Geophysical Gravity Inversion) were analyzed. The model was developed for the area of the Western Carpathians covering the Polish-Slovak border. A detailed assessment of the model's property was made regarding the accuracy of the disturbing potential values (height anomalies), gravity values, complete Bouguer anomalies (CBA), and differences between geoid undulations and height anomalies (N-zeta). Obtained accuracies of the GGI quasigeoid model (in terms of standard deviation of the residuals to the reference quasigeoid models) were at the level of +/- 2.2 cm for Poland and +/- 0.9 cm for the Slovak area. In terms of gravity, there was shown dependence of the accuracy of the GGI model on the digital elevation model (DEM) resolution, the point height, the density of gravity data used, and used reference density of topography model. The best obtained results of gravity prediction were characterized by an error of approximately 1 mGal. The GGI approach were compared with classical gravity prediction methods (using CBA and topographic-isostatic anomalies supported by Kriging prediction), getting very similar results. On the basis of the GGI model, CBA and differences (N-zeta) were also determined. The strong dependence of resolution of the CBA model obtained by GGI approach, on the size of the constant density zones, has been demonstrated. This significantly reduces the quality of such a model. The crucial importance of the topographic masses density model for both determined values (CBA and (N-zeta)) was also indicated. Therefore, for determining these quantities, all available information on topographic mass densities should be used in modelling.Web of Science1021art. no. 789

Quasi Geoid and Geoid Modeling with the Use of Terrestrial and Airborne Gravity Data by the GGI Method—A Case Study in the Mountainous Area of Colorado

This article concerns the development of gravimetric quasigeoid and geoid models using the geophysical gravity data inversion technique (the GGI method). This research work was carried out on the basis of the data used in the Colorado geoid experiment, and the mean quasigeoid (ζm) and mean geoid (Nm) heights, determined by the approaches used in the Colorado geoid experiment, were used as a reference. Three versions of the quasigeoid GGI models depending on gravity data were analyzed: terrestrial-only, airborne-only, and combined (using airborne and terrestrial datasets). For the combined version, which was the most accurate, a model in the form of a 1′×1′ grid was calculated in the same area as the models determined in the Colorado geoid experiment. For the same grid, the geoid–quasigeoid separation was determined, which was used to build the geoid model. The agreement (in terms of the standard deviation of the differences) of the determined models, with ζm and Nm values for the GSVS17 profile points, was ±0.9 cm for the quasigeoid and ±1.2 cm for the geoid model. The analogous values, determined on the basis of all 1′×1′ grid points, were ±2.3 cm and ±2.6 cm for the quasigeoid and geoid models, respectively