S U M M A R YThe Upper Silesian Coal Basin (USCB) in Poland is one of the most seismically active mining areas in the world. Seismic observations supported by the Central Mining Institute date back to the 1950s, and include an extensive mine tremors data bank, which has been in operation since that time. More than 55 900 mine tremors of energy E ≥ 10 5 J (local magnitude M L ≥ 1.5) occurred over the period 1974-2005. In the USCB, two types of tremors can be distinguished. These are the so-called 'miningtectonic' seismicity and 'mining' seismicity. The 'mining-tectonic' seismicity results from the interaction between mining and tectonic factors. These seismic events appear to be located in tectonically disturbed zones and their sources are visibly more energetic. The mine tremor source mechanism can mostly be the normal dip-slip fault with a marked strike-slip component in the source region. The rupture plane azimuths and dips of these seismic events correlate well with the strike and dip of the pre-existing local faults, in the vicinity of which the mine tremor sources have been located. The generalized mine tremor source mechanism of the events under consideration contributed a less than 15 per cent implosion component, an about 15 per cent uniaxial compressional component, and an about 70 per cent shear component to the total seismic moment tensor solution.The second one-'mining seismicity'-is strongly associated with the mining activity and seismic events that occur in the vicinity of active mining excavations. These events are energetically weak and their source mechanism can be of explosive type. The total seismic moment tensor is composed of: 20-50 per cent explosive component, practically the same amount of uniaxial compressional component and a very small amount of shear component (less than 10 per cent).

The paper compares the results of an approximate evaluation of mining tremors harmfulness performed on the basis of free-field and simultaneously measured building foundation vibrations. The focus is on the office building located in the Upper Silesian Basin (USB). The empirical Mining Intensity Scale GSI-GZW KW -2012 has been applied to classify the harmfulness of the rockbursts. This scale is based on the measurements of free-field vibrations but, for research purposes, it was also used in the cases of building foundation vibrations. The analysis was carried out using the set of 156 pairs ground -foundation of velocity vibration records as well as the set of 156 pairs of acceleration records induced by the same mining tremors.

Abstract:The paper presents the characteristics of seismic tremors and rockbursts that occurred between 2001 and 2015. The characteristics are based on a general description of the geological structure of the Upper Silesian Coal Basin (USCB). The level of seismic activity in the analysed period changed a number of times and depended on the intensity of mining works and diverse mining and geological conditions in each of the five regions where tremors occurred (Bytom Trough, Main Saddle, Main Trough, Kazimierz Trough, and Jejkowice and Chwałowice Troughs) and which belong to various structural units of the Upper Silesia. It was found out that in the case of rockbursts the phenomena were recorded in three regions. These are: Main Saddle, Bytom Trough, and Jejkowice and Chwałowice Troughs. The so called Regional Rockburst Indicator (RWT) was estimated for each of the regions where the rockbursts had been recorded. The obtained values of RWT are presented against the Probability of RockBurst (PT) in a given area.

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The influence of the kłodnica fault tectonic zone on the degree of damage to buildings resulting from high magnitude tremors Wpływ strefy tektonicznej uskokukłodnickiego na wielkość uszkodzeń w budynkach spowodowanych wysokoenergetycznym wstrząsem Abstract On 18 April 2015, a regional tremor with an energy E=4·10 9 J occurred in the main saddle of fault VIa. This phenomenon emerged as result of summing up of stresses caused by underground exploitation conducted in the vicinity of natural faults with unrelaxed tectonic stresses, which resulted in the very strong influence of this tremor on the surface infrastructure and on the emotional well-being of local people. This analysis suggests that there is a statistical relationship between these values. Diversity of location both of the size of measured vibration parameters, damages in the buildings and of feelings of the vibrations prove an unequal radiation of the seismic waves caused by the amplifying influence of the fault zone. Keywords: mining tremors, tectonic faults, mining damageStreszczenie 18 kwietnia 2015 r. w strefie uskokowej uskoku VIa w siodle głównym wystąpił wstrząs regionalny o energii E=4·10 9 J. Zjawisko to miało miejsce w wyniku sumowania się naprężeń wywołanych podziemną eksploatacją prowadzoną w otoczeniu naturalnych uskoków z niezrelaksowanymi naprężeniami tektonicznymi, co miało przełożenie na bardzo silne oddziaływanie tego wstrząsu na infrastrukturę powierzchniową i odczucia przez ludzi. Przeprowadzona analiza wykazała, że istnieje statystyczny związek między tymi wielkościami. Zróżnicowanie położenia zarówno wielkości pomierzonych parametrów drgań, uszkodzeń w budynkach, jak i odczuć wstrząsów świadczą o nierównomiernej radiacji fal sejsmicznych spowodowanej amplifikującym oddziaływaniem strefy uskokowej.Słowa kluczowe: wstrząsy górnicze, uskoki tektoniczne, szkody górnicze 54