Search

The Carpathian Orava Basin is a tectonic structure filled with Neogene and Quaternary deposits superimposed on the collision zone between the ALCAPA and European plates. Tectonic features of the south-eastern margin of the Orava Basin and the adjoining part of the fore-arc Central Carpathian Palaeogene Basin were studied. Field observations of mesoscopic structures, analyses of digital elevation models and geological maps, supplemented with electrical resistivity tomography surveys were performed. Particular attention was paid to joint network analysis. The NE-SW-trending Krowiarki and Hruštinka-Biela Orava sinistral fault zones were recognized as key tectonic features that influenced the Orava Basin development. They constitute the north-eastern part of a larger Mur-Mürz-Žilina fault system that separates the Western Carpathians from the Eastern Alps. The interaction of these sinistral fault zones with the older tectonic structures of the collision zone caused the initiation and further development of the Orava Basin as a strike-slip-related basin. The Krowiarki Fault Zone subdivides areas with a different deformation pattern within the sediments of the Central Carpathian Palaeogene Basin and was active at least from the time of cessation of its sedimentation in the early Miocene. Comparison of structural data with the recent tectonic stress field, earthquake focal mechanisms and GPS measurements allows us to conclude that the Krowiarki Fault Zone shows a stable general pattern of tectonic activity for more than the last 20 myr and is presently still active. [ABSTRACT FROM AUTHOR]

The article presents the results of consolidation tests of Neogene green clays from the geological profile of the Belchatów lignite mine (Central Poland). Reliable characteristics of the consolidation parameters are essential for forecasting settlements and for assessment of their insulation features. The reliability criteria of the test results for consolidation at a constant rate of loading are analysed. Quasistabilization of the cv value in the stress function sv may be used as a simple and effective criterion. Criteria based on comparisons with the theoretical course of the process indicate the key role of the steady phase of the test. In the analysed clays, a high consistence of the course of their consolidation with a theoretical solution in the steady phase was obtained. Corrections based on Wissa and Janbu suggestions or the reinterpretation of cv using theoretical rules introduced to CL tests are necessary, especially for the non-steady phase. [ABSTRACT FROM AUTHOR]

The article discusses the values of the permeability coefficient obtained in the consolidometric tests with continuous loading (CL) on samples of green clay from the Belchatów lignite mine. A wide range of differences in the coefficient value was compared to the values of pore water pressure with regard to total stress (the pore water pressure parameter CCL). On the basis of the obtained test results we present the possibility of an effective determination of the permeability coefficient for low permeability soils in consolidation tests conducted in the conditions of continuous loading. [ABSTRACT FROM AUTHOR]

The clear and detailed images of geological structures that can be obtained by seismic methods are one of the main drivers of their popularity in geological research. The quality of final geophysical images and models relies strongly on the amount of data that goes into them. Analysing several complementary seismic datasets allow an improved interpretation. Responding to this challenge, this article proposed an optimal combination of geophysical methods for near-surface applications. Multi-channel analysis of surface waves, first-arrival travel-time tomography, and ground-penetrating radar were the key supports for standard reflection seismic imaging. Ease of use and fast and cheap acquisition are some of the advantages of the mentioned methods. Considering that all recorded wave fields required minimal additional processing while offering a significant improvement in the final stack, it was worth the extra effort. Thanks to that, the better-estimated velocity filed allowed high quality images to be obtained up to 200 m. The Mesozoic bedrock was a distinct and very strong reflector in the resulting reflection seismic imaging. There was also a clearly visible depression of the horizon corresponding to erosion or a structure (syncline). Deeper, it was possible to track two or even four detachments of faulting origin. [ABSTRACT FROM AUTHOR]