In the Carboniferous rock mass of the Upper Silesian Coal Basin, large changes in the geomechanical conditions often occur over relatively short distances. These conditions relate to rock properties that are primarily responsible for the occurrence of geodynamic phenomena in the rock mass. The main factor influencing the manifestation of these phenomena is tectonic stress developed during Variscan and subsequent Alpine orogenesis. This stress contributed to creating tectonic structures in the Carboniferous formations and influenced the properties of the rocks themselves and the rock mass they form. As a result of the action of the stresses, compaction zones (main stresses were compressive) were formed, along with zones in which one of the main stresses was tensile. For the compaction zones in the Carboniferous rocks, the following geomechanical parameters have been calculated: uniaxial compressive strength, Young’s modulus and post-critical modulus. The local stress field was determined according to the focal mechanism in selected areas (Main and Bytom troughs) to characterize changes in geomechanical properties of the rocks that are responsible for high-energy tremors (E ≥ 106 J, ML ≥ 2.2).

The solutions presented permit the practical determination of the physical parameters of peak ground vibration, caused by strong mining tremors induced by mining, in the Polish part of the Upper Silesian Coal Basin (USCB). The parameters of peak ground horizontal velocity (PGVH) and peak ground horizontal acceleration (PGAH10) at any point of earth’s surface depend on seismic energy, epicentral distance and site effect. Distribution maps of PGVH and of PGAH10 parameters were charted for the period 2010-2019. Analysis of the results obtained indicates the occurrence of zones with increased values of these parameters. Based on the Mining Seismic Instrumental Intensity Scale (MSIIS-15), which is used to assess the degree of vibration intensity caused by seismic events induced by mining, and using the PGVH parameter, it was noted that the distribution map of this parameter includes zones where there vibration velocities of both 0.04 m/s and 0.06 m/s were exceeded. Vibrations with this level of PGVH correspond to intensities in the V and VI degree according to the MSIIS-2015 scale, which means that they can already cause slight structural damage to building objects and cause equipment to fall over. Moreover, the reason why the second parameter PGAH10 is less useful for the evaluation of the intensity of mining induced vibrations is explained. The PGAH10 vibration acceleration parameter, in turn, can be used to design construction of the objects in the seismic area of the Upper Silesian Coal Basin, where the highest acceleration reached a value of 2.8 m/s2 in the period from 2010 to 2019.

Neotectonic structures of the Upper Silesia that originated during the last 5 Ma (Pliocene and Quaternary) overlap Miocene grabens and horsts of the Carpathian Foredeep. They had been reactivated in Pliocene as an effect of the young Alpine uplift of the Carpathian Foredeep. It is postulated that ice-sheet derived compaction of a thick Miocene deposits was the most significant agent of the development of neotectonic depressions. Glacioisostasy of mobile bedrock structures was presumably also an important component of vertical movements. The amplitude of neotectonic movements is estimated to 40-100 m, basing on DEM map analysis, analysis of sub-Quaternary structural maps, and the Pleistocene cover thickness. The present-day tectonic phenomena are generated by mining-induced seismicity. These are connected with stress relaxation in the deep bedrock thrust zones of the Upper Silesian Coal Basin.