Seismo-tectonic characteristic of M5 seismic event near Humenne (Slovakia) in view of regional and temporary seismic networks

Abstract The strongest in Western Carpathians (WC) in XXI century M5 earthquake occurred on 9 October 2023 near Humenne (Slovakia). It was widely felt in Slovakia and Poland, what is rare. It occurred in complex tectonic setting formed with overthrusted frontal nappes and rotated internal lithospheric units. The present tectonic regime of the WC is resulting with vertical movements related to convergence of the WC and of the stable European Platform. Since the complex tectonic setting may influence the estimates of the source parameters, we propose to use local velocity model and regional and temporary seismic stations available within the time of the event occurrence from different projects: AdriaArray, Polish Geological Institute—National Research Institute monitoring network and broadband stations available from Polish, Slovak and Hungarian national seismological networks. Basing on the local velocity model derived from the earlier seismic experiments we obtained similar location and magnitude estimates as EMSC and NEIC, however our focal mechanism is significantly different. Usage of the above-described data improved the precision of the focal mechanism solution and of the depth location of the studied event. Obtained solutions suggest that focus was located at 10–15 km depth and had orientation of strike-slip fault with significant reverse fault component of strike parallel to the main discontinuities in this region and to the PKB (Pieniny Klippen Belt), which follow the trend of the Carpathian Mountains arc or perpendicular to above-mentioned main structures NE-SW strike in agreement with minor discontinuities and main compressional trend in this area.