A brittle tectonic study has been carried out in the crystalline limestone and granite quarries near Vápenná village in the Rychlebské hory Mts. in the NE part of the Bohemian Massif. The quarries are situated along the Sudetic Marginal fault zone - the most important tectonic structure of the area. At the lo cality, the Sudetic Marginal fault separates Devonian crystalline limestones of the Branná group and Paleozoic granites of the Žulová pluton. Hundreds of measurements of joints and small-scale faults were taken in three limestone quarries on the west side of the fault. Kinematic indicators were observed as well. Equivalent measurements and observations have been performed on the fault east side in several small granite quarries. In the limestones three sets of fault have been identified (the W-E subvertical, the Sudetic NW-SE falling 45° to NE and the N-S falling 75° to W). The W-E direction of faults is the most importa nt direction there. There are two sets of faults in the granites (the subvertical Moravo-Silesian NE-SW and the Sudetic NW-SE). The NE-SW direc tion is dominant. There are almost none subhorizontal faults in the studied area., Lucie Nováková., and Obsahuje bibliografické odkazy
Large amounts of abandoned limestone quarries in the Bohemian Karst provide a great opportunity to study different stages of spontaneous succession simulta - neously. Molluscs are a suitable model group for this study –many land snail species including the rare ones occur in these quarries. Because of the large variability of habitats, quarries abandoned for around 60 years have higher species diversity. and Alena Kocurková, Lucie Juřičková.
The present paper describes a method for identification of reflected waves on the seismogr ams from a cluster of quarry blasts. These reflections are used for determination of the Moho depth. Only one seismic station is sufficient, but a cluster of seismic sources is needed. To increase the signal-to-noise ratio of reflected waves, several techniques are applied, such as filtering, polarisation analysis and stacking of seismograms. Th e method was tested on seismic data from the central part of the Ore Mountains region, Czech Republic. Seismic waves were generated by strong quarry blasts at the Tušimice open-pit coal mine, and recorded at the Přísečnice (PRI) temporal seismic station at an epicentral distance of about 16 km. As the station was equipped with a three-component seismograph, also S-wave onsets could be determined. Although Pg, Sg and surface waves dominate the seismograms, weak Moho reflections of P and S waves could also be recognized at travel times of 9.7 s and 17.3 s, respectively. From these times we found the mean ratio of the P- to S-wave ve locities in the crust to be 1.78. Considering P-wave velocity model of Beránek (1971), the observed travel times of the reflections yield a crustal thickness of 29.5 -n31.5 km, which agrees with recent receiver function studies. These agreements indicate that the proposed method of reflected seismic waves, generated by quarry blasts, could represent a simple way for mapping the Moho discontinuity., Hana Kampfová, Jiří Málek and Oldřich Novotný., and Obsahuje bibliografické odkazy