The Lithospheric structure of the Western Carpathian-Pannonian Basin region based on the CELEBRATION 2000 seismic experiment and gravity modelling

The lithospheric structure of the Western Carpathian–Pannonian Basin region was studied using 3-D modelling of the Bouguer gravity anomaly constrained by seismic models and other geophysical data. The thermal structure and density distribution in the shallow upper mantle were also estimated using a combination of petrological, geophysical, and mineral physics information (LitMod). This approach is necessary if the more complicated structure of the Pannonian Basin is to be better constrained. As a result, we have constructed the first 3-D gravity model of the region that combines various geophysical datasets and is consistent with petrological data. The model provides improved estimates of both the density distribution within the lithosphere and the depth to major density discontinuities. We present new maps of the thickness of major sedimentary basins and of the depth to the Moho and the lithosphere–asthenosphere boundary. In our best-fitting model, the Pannonian Basin is characterised by extremely thin crust and lithospheric mantle, both of which have low density. A low-density uppermost asthenospheric mantle layer is also included at depths of 60–100 km. The Western Carpathians have only a thin crustal root and moderate densities. In contrast, the European Platform and Eastern Alps are characterised by lithosphere that is considerably thicker and denser. This inference is also supported by stripped gravity anomalies from which sediment, Moho and asthenospheric gravity contributions have been removed. These residual anomalies are characteristically low in the Western Carpathian–Pannonian Basin region, which suggests that both the ALCAPA and Tisza–Dacia microplates are ‘exotic terranes’ that are markedly different to the European Platform.16 page(s

Pliocene to Quaternary stress field change in the western part of the Cen tral West ern Carpathians (Slovakia)

Knowledge of the current tectonic regime plays an essential role in natural hazard assessment, especially in the risk assessment of fault activity. Structural analysis of brittle deformations (using in version techniques) was used to determine the stress field state occurring within Pliocene and Quaternary deposits in the western part of the Central Western Carpathians. The deformation pattern of the reduced stress tensor showed that all structural measurements could be separated into two groups. An older, Late Pliocene fault population was activated un der NNW-SSE oriented extension. A younger, Quaternary fault population reflected origin in a NE–SW extensional tectonic regime and it distinctly showed a change the orientation of the S3 of about 70. The change in tectonic activity, as well as in the stress field orientation, is dated to the Pliocene-Pleis to cene boundary. The Quaternary stress field developed dur ing the post-collisional stage of the orogen. Our study shows that the West ern Carpathian internal units document NE-SW to NNE-SSW extension in the broader region around of the north ern Danube Basin

Lithosphere in the Western Carpathians and its surrounding tectonic units - Geophysical study

Geophysical methods are important tools for the investigation of the structure and geodynamic development of the lithosphere. The central and eastern parts of the Western Carpathians are bordered in the north by a thicker  and stronger lithosphere of the European platform (100-150  km), which is underthrust (about of 50 km) beneath the margin of the overriding Carpathian orogen. This thickening is interpreted as remnants of subducted slabs. In contrast, the “thin” lithosphere at the western margin of the Western Carpathians can be considered as a result of oblique collision along a deep-seated transform zone between the platform and orogenic lithosphere. Neo-Alpine “soft” collision and retreating subduction of this orogen can also be discovered by means of quantitative interpretation of observed gravity field. The crustal thickness in the Western Carpathians ranges among 27-35 km. The central Western Carpathians are characterized by thicker crust (30-55 km) in comparison with thinner crust (25-30 km) in the Pannonian Basin System. This feature is probably the result of the youngest lithosphere processes from the Middle Miocene. Rheological properties of the Western Carpathian lithosphere show that the mechanical strengths decrease within the whole lithosphere from the area of the European platform via the Western Carpathians to the Pannonian Basin. The most remarkable and important first-order tectonic structures (seismo-tectonic zones) in  the Western Carpathians are the zones of the Pieniny Klippen Belt, the Mur-Mürz-Leitha fault zone, the Čertovica fault zone and the Hurbanovo line. Map of neo-Alpine fault systems and neotectonic regions (blocks) of  Slovakia was defined

Integrated interpretation of geophysical fields - Implications for the tectonic structure of the Mochovce nuclear power plant

The contribution contains of the geophysical data and their interpretation. Interpretation of geophysical fields in compliance with the geological structure and geodynamics EMO far region contributes significantly to development of  seismo-tectonic model. The model represents the correlation between seismic activity and geological-tectonic setting. The achieved seismo-tectonic model in fact reasons all recorded seismic events in the area and points out to a seismic activity decrease towards the Danube Basin center,  thereof, there being situated the EMO locality

Acceleration of late pleistocene activity of a central European fault driven by ice loading

We studied the southern part of the NW-SE trending Sudetic Marginal fault (SMF), situated at the northeastern limit of the Bohemian Massif in central Europe, to assess its Quaternary activity. Eighteen trenches and thirty-four electric resistivity profiles were performed at Bílá Voda to study the fault zone and 3-dimensional distribution of a beheaded alluvial fan on the NE side of the fault. We interpret a small drainage, located about 29–45 m to the SE of the fan apex, as the only plausible source channel implying a similar amount of left-lateral offset. The alluvial fan deposits’ radiometric ages range between about 24 and 63 ka, but postglacial deposits younger than 11 ka are not displaced, indicating that all motion occurred in the late Pleistocene. The site lies ∼150 km south of the late Pleistocene Weichselian maximum (∼20 ka) ice sheet front. We model the effects of the ice load on lithospheric flexure and resolved fault stresses, and show that slip on the SMF was promoted by the presence of the ice sheet, resulting in a late Pleistocene slip rate of ∼1.1+2.3/−0.6 mm/yr. As the most favorable time for glacial loading-induced slip would be during the glacial maximum between about 24 and 12 ka, it is doubtful that the slip rate remained constant during the entire period of activity, and if most slip occurred during this period, the short-term rate may have been even higher. Considering that the modern maximum principal stress (σ1) is oriented nearly parallel to the Sudetic Marginal fault (NNW-SSE) and is thus unfavorable for fault motion, our observations suggest that the likelihood of continued motion and earthquake production is much lower in the absence of an ice sheet