Classical Russian pendulum seismometer S-5-S was modified for recording of the rotational components of ground motion around the vertical or horizontal axes; the modified sensor is denoted here as S-5-SR. Experimental field testing of the S-5-SR sensor started in December 2010 in the Karvina coal region that is known as an area of intensive mining induced seismicity. First seismic station was installed in Doubrava village characterized by thick sedimentary layers. Next seismic station was installed in Orlova village, in different local geological conditions, i.e. in region without sedimentary layers. More than 200 mining induced seismic events were recorded on each seismic station during the period of six months of seismic monitoring. The recorded wave patterns confirm the existence of rotational ground motion components in this region; the strongest recorded value of this component exceeded 1 mrad.s-1. Analysis of the obtained records is presented in this paper., Zdeněk Kaláb, Jaromír Knejzlík and Markéta Lednická., and Obsahuje bibliografii
The paper presents selected results of seismological observations in Silesia and northern Moravia between 01/2004 - 08/2008, which are based on interpretation of three-component digital recordings at solitary seismic stations operated by the Institute of Geonics of the ASCR Ostrava (IGN) distributed in the region under investigation. Five seismic stations had recorded local tectonic seismic events in a continuous regime until 12/2005, when the grant project GA CR No. 205/03/0999 terminated. Meanwhile, the Ostrava - Krásné Pole (OKC) seismic station have continued in operation as a part of the Czech regional seismological network since 1983 up to present. Other three stations have been operating in a so-called triggered regime. At the mid-January 2007, seismic station in Klokočov village was re-opened in continuous regime. During 55 months of observation, 90 tectonic events have been detected at one or more seismic stations mentioned above. However, database of the Institute of Physics of the Earth of the MU contains more than 640 microearthquakes during the same time. This discrepancy is caused mainly due to a higher concentration of microearthquake foci distributed all over the western part of the region under investigation where the IPE seismic stations are situated. On the other hand, the IGN seismic stations are spread predominantly within the eastern part of the territory, i.e. relatively far from the recent foci, and moreover, some stations are operated using the triggered regime., Karel Holub, Zdeněk Kaláb, Jaromír Knejzlík and Jana Rušajová., and Obsahuje bibliografii
Experimental geomechanical and seismological measurements are performed in the medieval Jeroným Mine near Čistá (Sokolov district). The main aim of this activity is geomech anical stability evaluation of this monument. Periodical monitoring was started in 2001 whereas quarterly period was applied (measurement of crack development in the mine working, development in changes in convergence cross-sections of linear and spatial workings and fluctuations of water levels in underground spaces). Seismological monitoring was started during reconstruction of partly impassable drainage adit. At present, selected parts of described geomechanical system are newly instrumented to obtain continuous information. Data obtained from periodical and continuous monitoring are presented in this contribution. Interpretation of seismological data on both natural and technical seismicity and fluctuations of water levels is presented in details., Zdeněk Kaláb, Jaromír Knejzlík, Robert Kořínek, Radovan Kukutsch, Markéta Lednická and Petr Žůrek., and Obsahuje bibliografické odkazy
The essential point for seismological observation in the northern part of Moravia, Czech Republic, is a permanent seismic station Ostrava - Krásné Pole (OKC) that is a part of the Czech regional seismological network (hereafter CRSN). Institute o f Geonics AS CR, v.v.i., has also operated temporary seismic stations in this region since 1997. Current seismological stations are located in an abandoned mine working located in Zlaté Hory and in cellars in Klokočov and castle Raduň near Opava. The natural seismicity is after the swarm of microearthquakes in the vicinity of Opava in 1993 very low now. In region under discussion, seismic manifestations generated by mining induced seismicity in Upper Silesian Coal Basin (both Karviná an d Polish parts) and in Legnica-Głogów Copper District (LGOM) are also detected. Significant part of observations in this region is made by the Institute of Physics of the Earth (hereafter IPE), Masaryk University Brno, and about 1000 microearthquakes have been detected during the last ten years with maximum local magnitude up to 1.9., Zdeněk Kaláb, Jaromír Knejzlík and Karel Holub., and Obsahuje bibliografické odkazy
The paper presents the results of experimental examination of the weathering grade of granite rock mass in the medieval Jeroným Mine (Czech Republic). This mine is declared as a cultural heritage site of the Czech Republic therefore, non-destructive methods for determination of the Schmidt hammer rebound value and the ultrasonic pulse velocity were used to minimize negative impact on the historical workings during in situ exploration. Weathering grade of selected parts of the rockmass in underground spaces was classified visually according to the assumed classification (Hencher and Martin, 1982 in Vahed et al., 2009) and the above mentioned measurements were performed in these parts. Results show that the rebound value and the ultrasonic pulse velocity are decreasing with increasing weathering grade for all investigated parts. Therefore this result is possible to use as a supplementary method for evaluation of weathering grade of rock massif in this mine., Markéta Lednická and Zdeněk Kaláb., and Obsahuje bibliografické odkazy
Russian electrodynamic seismometer named S-5-S is adaptable for measurement of rotational ground motion. In this paper brief information about mentioned adaptation is presented. Initial results from experimental m easurement in Karviná region in 2011 with high mining induced seismicity are documented. Measured values for the horizontal component reached up to 1 mrad s-1 , while the seismic energy of these events did not exceed the value of 10 5 J and hypocentral distances were within 2 km., Zdeněk Kaláb and Jaromír Knejzlík., and Obsahuje bibliografické odkazy
The oldest mine cavities of the Jeroným Mine were already mined out more than 400 years ago. That is why it is necessary to determine the stability of individual parts of underground spaces. The assessment of stability of mine cavities is based on the long-term monitoring of chosen parameters. A distributed measurement network has been operated here using several different types of sensors. A laser distance meter that is used for measuring the height of a large chamber is one of these sensors. The results obtained from this monitoring are presented. Even if no apparent correlation seems to be visible between Earth’s tides and LDM variations, some features of recorded data, like dynamical frequency crossover in the power spectrum, could be due to the tidal cycles of the Earth., Zdeněk Kaláb, Markéta Lednická, Jaromír Knejzlík and Luciano Telesca., and Obsahuje bibliografii
Evaluation of seismic loading in urban areas is not a simple process. The horizontal to vertical spectral ratio method technique has been often used for determination of site effect recently. Results from the re-interpretation of mining induced seismic events from Karviná region in frequency domain using archival databases will be presented in this study material. Also, spectra of continuous records (a bout two days) and evolution of spectra within a moving time window of the length 10 seconds are presented. These continuous records were registered on two places with different geological conditions., Zdeněk Kaláb and Alexey A. Lyubushin., and Obsahuje bibliografické odkazy