Earthquake swarms are a well-known geophysical phenomenon in the Vogtland region and in north-west Bohemia (Czech Republic). These earthquake swarms usually consist of a large number of many small quakes that cause no damage to buildings and are barely felt by the population. However, on the afternoon of 1 January 2026, five stronger earthquakes with magnitudes between 2.3 and 3.2 occurred and were reported by the population. The earthquakes were recorded by the Seismology and Seismology working group at the Institute of Geophysics and Geoinformatics.
"The current swarm earthquake activity began on 20 November 2025, with noticeable events on St. Nicholas Day (6 December 2025) and in the night from 10 to 11 December, among others. The currently seismologically active area is located near Luby in the Czech Republic," says research associate Catherine Alexandrakis-Zieger. Previous major swarms occurred in 2014, 2017 and 2018, among other years.
Recording and researching the causes of these earthquake swarms is a central focus of the Seismology and Seismology working group at TU Bergakademie Freiberg. Since February 2025, it has been operating the Saxon Seismological Network "Sachsennetz", which is part of the Central German Seismology Network and is funded by the Saxon State Office for the Environment, Agriculture and Geology (LfULG). The network currently comprises 22 measuring stations in Saxony and Saxony-Anhalt. "The real-time data is automatically analysed and then manually checked to distinguish between earthquakes, induced earthquakes and non-tectonic signals such as explosions," explains Alexandrakis-Zieger.
In addition to the continuous monitoring of seismic activity, the working group is investigating the geological structures of the earth's crust in the Vogtland region and in north-west Bohemia. The aim is to understand the processes that lead to the formation of earthquake swarms. To this end, the researchers analyse natural earthquake data and carry out active seismic experiments in the field. The investigations provide high-resolution images of seismically active faults and geological interfaces in the subsurface. This work is carried out in close collaboration with German and Czech research institutions and contributes significantly to the understanding of seismic activity in the region.
