High energy events as a combined effect of human impact and geoenvironmental factors - the case study based on GNSS data

coal production has been gradually reduced for many years.
Nevertheless, the number of high-energy tremors remains at a
similar level or decreases much slower than production. We analyze
this problem in the aspect of geological setting and on the base of
geodetic data. We explain the paradox by specific interaction
between man-induced and natural tectonic stress as seasonal
hydrological effects. Anomalous energies released during large
seismic events exceeded the predetermined threshold, typical for
mining tremors in the area. Further, the authors point out the
seasonal occurrence of these events.
Temporal variations of distances between continuously operating
GNSS (Global Navigation Satellite Systems) reference stations
were analyzed, and linear strain, inferred from these geodetic
observations, corresponded to high-energy tremors in the area.
Consequently, the seismic events usually occurred when the
analyzed baseline performance demonstrated significant seasonal
increases or decreases of evaluated temporal distribution of strain.
The aim of the analysis was to evaluate the relationships between
the characteristics of the time series of deformations and the
occurrence of seismic tremors of energy E ≥ 3 x 107
J occur.
Seasonal occurrences of high-energy seismic events as the energy
they released suggest the influence of environmental factors.