News

Two months after the earthquake in southwestern Slovakia with the epicentre near the town of Šamorín, the Institute of Earth Sciences of the Slovak Academy of Sciences, in cooperation with the Faculty of Mathematics, Physics and Informatics of the Comenius University in Bratislava, completed a preliminary analysis of the seismic phenomenon, which was the strongest in western Slovakia in the last several decades.

Several significant and new facts

• The main tremor occurred on Saturday, February 21, 2026, at 1:44 p.m. local (Central European Time). The local magnitude (ML) was determined to be 4.3.
• The epicentre was originally located near Rohovce, but after detailed analysis and reinterpretation of relevant data from all available seismic stations (including those from abroad), it was relocated between the municipalities of Báč and Trnávka, i.e. approximately 4 km further north, which corresponds more with the extent of damage in individual municipalities, as well as with observations and testimonies of the inhabitants of the municipalities. The depth of the focus (hypocenter) is approximately 8 km.
• By the end of April, 52 aftershocks occurred; the last localised aftershock was on April 17, 2026, with ML = 1.6. Eight aftershocks were macroseismically felt in the epicentral area. The strongest aftershocks occurred on March 10, 2026, in the morning and evening hours, with ML = 3.3 and ML = 3.0.
• The Institute of Earth Sciences of the SAS received and evaluated 7,688 macroseismic electronic questionnaires for the main shock; over 2,400 questionnaires were from Bratislava.
• Based on the information available so far, the epicentral macroseismic intensity was determined to be 6-7 EMS-98 in the municipality of Báč. In 16 municipalities (or parts of municipalities), the intensity was determined to be 6 EMS-98: Šamorín, Čilistov, Kráľovianky, Mliečno, Bučuháza, Horný Bar, Šuľany, Vojka nad Dunajom, Blatná na Ostrove, Veľká Paka, Malá Paka, Čukárska Paka, Rohovce, Trnávka, Kyselica, and Dobrohošť.
• In Bratislava, the earthquake was felt most strongly in the Bratislava V district (especially high-rise buildings in Petržalka), Bratislava II - Podunajské Biskupice, Vrakun, Prievoz, Prístav, where the intensity was determined to be 5 EMS-98. In other parts of Bratislava II (e.g., Ružinov) and in the districts of Bratislava I (Staré Mesto), Bratislava III (Nové Mesto, Rača), and Bratislava IV (except Záhorská Bystrica), the intensity was 4-5 EMS-98. The
• earthquake was also observed in more distant cities such as Piešťany, Trenčín, Prievidza, and Vienna.
• Information on the effects of the earthquake in individual municipalities and city districts was distributed to insurance companies.
• A moment magnitude of 4.0 was determined for the main shock. This number indicates that, theoretically, the earthquake occurred over an area approximately 1 km by 1 km, as evidenced by the formation of a 1 km-long crack at the focus. This corresponds to approximately 5 cm of displacement at the focus, i.e., at a depth of about 8 km, and a manifestation on the surface of the order of a few mm, which is practically invisible in irreversible surface deformation.
• Minor damage was recorded on buildings, including capillary cracks in walls and plaster, smaller and larger pieces of plaster falling off, damage to tiles and paving, and isolated damage to glass fillings and chimneys.
• An important structural-tectonic factor was the determination of the focal mechanism, i.e., the nature of the relative motion between two rock blocks. The movement was determined to be a right-sided horizontal shift in the direction north-northeast to south-southwest.
• The determined nature of the fault and the direction of movement correspond very well with the observations of people who described the perceived direction of movement south-north.
• The current sequence of localised earthquakes in the vicinity of Šamorín most likely corresponds to the Čifer fault, which was previously identified based on other geological and geophysical data in the southwestern part of the Danube Plain.
• From publications about the town of Šamorín, we learn of earthquakes in the 18th century, previously assumed to be from the Komárno focal zone (1759, 1763, 1783, and their aftershocks). The church visitation book from 1781 states that there were two crypts in the then church of the Pauline Order. Due to frequent earthquakes, many cracks developed in their construction, preventing access to them from the outside.
• Past earthquakes also damaged the Roman Catholic church in Štvrtek na Ostrov. In 1590 (the earthquake had its epicentre in Lower Austria near the village of Neulengbach), the north tower collapsed. Another earthquake felt in Štvrtek na Ostrov is reported in the Liber Cronicae Csotortokiensis LCCS. S. Jacob Anno 1677 (accounting book of the parish of Štvrtok na Ostrove). The epicentre and magnitude of this earthquake have not yet been determined and therefore require further research of historical sources.

Prepared by: Ján Madarás, Lucia Fojtíková, Kristian Csicsay, Róbert Kysel, Adrián Michálek, Andrej Cipciar, Peter Pažák, Institute of Earth Sciences SAS

Martin Gális, Jozef Kristek and Miriam Kristeková from FMFI Comenius in Bratislava also actively participated in the research.