Tectonic movements monitored in the Bohemian Massif

This paper provides evidence for recent geodynamic activity within the Sudeten and Krušné Hory Mts. Fault Zones of the Bohemian Massif, Central Europe. Data were recorded using crack gauges and tiltmeters located on specific geological structures within caves and galleries. These data are supported by rangefinder, seismic, and groundwater observations. It is shown that a significant pressure phenomenon, here termed a pressure pulse, occurred during 2003. The pressure pulse initiated a series of tectonic deformations. In the Krušné Hory Mts., the pulse was preceded by chaotic tilt movements followed by significant tilt reorientation. Several stages of the deformation process were determined, analysed, and described. These stages represent stability, relaxation, compression, compaction, and later relaxation. The pressure pulse itself was associated with the compressional stage. Moderate, but regionally significant, earthquakes occurred during the later stages of the deformation process. This precludes the idea that they might be responsible for the initiating the recognised movements. At the same time, an unusual sequence of earthquake micro-swarms occurred in West Bohemia. These events should all be seen as the result of tectonic deformation initiated by the pressure pulse. Supplementary data indicate an affinity between the deformation process and large global disturbance within the Earth's crust (Stemberk et al., 2010).

Research highlights▶ An aseismic tectonic pressure pulse struck Europe in 2003 and induced years of increased geodynamics. ▶ Fault gauging, tiltmeters, groundwater level records from the Bohemian Massif were analysed during the movements. ▶ Local earthquakes occurred in the relaxation phase of the process.