Authors:L. L. A. Vermeersen, R. Riva, and R. Sabadini
The 3D quasi-static displacements during and following an earthquake provide a wealth of information on the internal structure and rheological properties of the Earth. If an earthquake occurs in a region that has shallow-viscosity zones inside the crust or at the top of the mantle (asthenosphere), then post-seismic displacements of the crust on the order of millimeters per year are possible. These can be detected by means of permanent GPS stations in the years following a faulting event. In this paper we systematically study the influence of viscoelastic simulation model restrictions on co- and post-seismic deformation. Examples include stratification of the Earth model, modeling of the seismic source, influence of compressibility, effects of position and viscosities of shallow low-viscosity layers. It will be shown that some of these model restrictions or assumptions can have non-negligible influences on the simulated 3D co- and post-seismic displacements.
Authors:M. Bielik, J. Šefara, M. Kováč, J. Hók, J. Vozár, and H. Zeyen
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.