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The National Network of Seismic Stations of Slovakia (NNSS) consists of eight short period and five broadband permanent seismic stations and a data centre located at the Earth Science Institute of the Slovak Academy of Sciences (ESI SAS). The NNSS recorded and detected 10888 seismic events from all epicentral distances in 2016. Totally 87 earthquakes originated in the territory of Slovakia in 2016. This paper provides basic information on the configuration of the NNSS, routine data processing, seismic activity on the territory of Slovakia in 2016 as well as macroseismic observations collected in 2016.

The National Network of Seismic Stations of Slovakia (NNSS) consists of eight short period and five broadband permanent seismic stations and a data centre located at the Earth Science Institute of the Slovak Academy of Sciences (ESI SAS). The NNSS recorded and detected 11,487 seismic events from all epicentral distances in 2019. Totally 91 earthquakes originated in the territory of Slovakia in 2019. This paper provides basic information on the configuration of the NNSS, routine data processing, seismic activity on the territory of Slovakia in 2019 as well as macroseismic observations collected in 2019.

We present the state of the modernized, upgraded and enhanced National Network of Seismic Stations (NNSS) of Slovakia at the end of the year 2017 and the importance of the Project: Modernization and enhancement of the National Network of Seismic Stations which took place in years 2001–2004. In this period some stations were modernized and upgraded and several new stations were built in various places in Slovakia to increase ability to localize seismic events on the territory of Slovakia and adjacent areas. Before the year 2001 the average number of localized earthquakes on the territory of Slovakia was only 7 per year. The breakthrough occurred in the year 2005 with the fully operational network when the number of localized earthquakes with epicentre on the territory of Slovakia was increased up to 50. Now this number is approximately 70–90 earthquakes per year. We present the changes in the NNSS in the last 13 years, obtained results (some of them are preliminary), advantages and weaknesses of the NNSS and future plans toward further improvements of our seismic network system.

We have analyzed 44 micro-earthquakes with magnitudes between 1.2 and 3.4, which occurred in the Dobra Voda area, Slovakia, in the period 2001–2009. The epicentres of the micro-earthquakes form a cluster elongated in the ENE–WSW direction. This direction coincides with the orientation of the main fault systems in the area: Dobra Voda and Brezova faults. The depths of the hypocentres vary from 1 km to 14 km. Three different methods were used to calculate the focal mechanisms: (a) a method using the polarities of Pg and Pn waves, (b) the P-wave amplitude inversion of moment tensors, and (c) the waveform inversion of moment tensors. The majority of the analyzed micro-earthquakes have a left-lateral strike-slip focal mechanism with weak normal or reverse components. The full moment tensors comprise significant non-double-couple (non-DC) components. The non-DC components are partly numerical errors of the inversion but might be also of a physical origin. The most accurate values of the non-DC components are obtained from the P-wave amplitude inversion. For this inversion, the isotropic component (ISO) and the compensated linear vector dipole component (CLVD) are mostly positive and well correlated. This might indicate tensile faulting. Adopting the model of tensile faulting, we estimated the mean ratio of P to S wave velocities in the focal area from the values of ISO and CLVD, vP/vS = 1.5–1.6. The three different datasets of the focal mechanisms have been inverted for the present-day tectonic stress in the Dobra Voda area. The slip shear stress component criterion was applied in the stress inversion. The results of the three inversions are well-consistent and point to a high reliability and good accuracy of the inverted stress. The orientations of the principal stresses are (azimuth/plunge): σ1 = 210–220°/5–25°, σ2 = 70–105°/55–75°, and σ3 = 305–315°/15–25°, and the shape ratio is R = 0.45–0.60. The azimuth is measured clockwise from the north and the plunge downwards from the horizontal plane. The retrieved maximum compression lies along the belt of the Male Karpaty Mts. The local tectonic stress reflects complex tectonic conditions in the area. The presence of tensile faulting might point to an extensional stress regime in the area.

A sequence of explosions occurred in an ammunition factory in Novaky, Slovakia, on 2 March 2007 and caused a major industrial accident. The origin times and number of explosions were key aspects for the state investigation team to explain the primary cause and development of the accident. An analysis of seismic records was the only way to determine reliable origin times. We were able to identify the two strongest explosions directly from the seismic records. Detailed time-frequency analysis enabled us to identify acoustic waves caused by the explosions. This led to the subsequent identification of two weaker explosions in seismic records and an indication of two even weaker explosions that could not be identified in the records. The seismic analysis is supported by results of the onsite investigation by the state investigation team.

This paper presents an overview of seismic and mass movement hazards affecting major Hydropower-plants (HPP) and ongoing dam projects in the mountain regions of Central Asia. HPP cascades are located along the Naryn River in the Kyrgyz Republic and the Vakhsh-Surkhob valley fault zone in Tajikistan. The latter region hosting the presently and future tallest man-made dams of the world is very prone to earthquakes and various types of slope instabilities. The Naryn Valley hosting several dam sites is marked by the presence of ancient rockslides and a dense network of seismically active faults. In December 2009, Kyrgyz, Russian, Slovak and Belgian teams have monitored seismic ground motions and displacements induced by the blasting of a slope on the Kambarata 2 site producing a 35 m–high blockage on the Naryn River. This work is part of a NATO Science for Peace and Security project on landslide dam hazards in the Tien Shan.