Czechia

Czechia sits in the Bohemian Massif, a large Variscan basement block that is among the more stable crustal fragments in central Europe. Seismicity is generally low, but the country hosts one of Europe's most scientifically interesting phenomena: earthquake swarms in the western Bohemia–Vogtland region near the German border. These swarms, typically centered around Nový Kostel and Cheb Basin, consist of hundreds to thousands of small earthquakes (generally below [[magnitude]] 4) occurring over weeks to months, then ceasing for years before recurring. The swarms are thought to be driven by the episodic degassing of mantle-derived CO₂ through a deep crustal [[fault]] system, making them a unique hybrid between tectonic and magmatic seismicity. Outside this region, shallow crustal earthquakes occur sporadically across Moravia and the Sudeten area but rarely exceed M 4.

The Nový Kostel swarms are among the best-studied earthquake sequences in Europe. Major swarm episodes occurred in 1985–86, 1997, 2000, 2008, 2011, 2014, and 2018, with the strongest individual events reaching ML 3.8–4.4. While no significant structural damage has resulted, the repeated swarms are keenly felt by local residents and generate intensive scientific scrutiny. Beyond western Bohemia, the 1897 Šternberk earthquake in Moravia (M ~5.5) was one of the strongest historical events within Czech territory, causing damage to masonry buildings. Silesian mining operations have also contributed to induced seismicity, though at lower levels than in Polish Silesia.

The geological context of Czech seismicity involves the Eger Rift — a Cenozoic continental rift that extends from western Bohemia into Germany — and the associated Mariánské Lázně Fault Zone. The rift is tectonically inactive at the surface but appears to channel crustal fluids (primarily CO₂) upward, modulating pore pressure along faults and triggering the distinctive swarm behavior. Czech seismic networks are dense and modern in the Bohemia–Vogtland zone, providing world-class monitoring data that has advanced understanding of fluid-induced seismicity globally.