a2_The town of Litija was hit by four damaging earthquakes in the last 120 years which reached a maximum intensity of VII-VIII MSK. The town is located in a shallow sedimentary basin filled with relatively soft Quaternary sediments in which seismic site amplification is expected. On the other hand no borehole or geophysical data are available to support quantitative assessment of site effects. As a contribution to the first seismic microzonation of the area, we performed a free-field study based on the microtremor HVSR method in order to assess the resonance frequency of th e sediments. In ge neral clear spectral peaks were obtained for 57 measuring points which show distribution of frequencies in a broad range between 4.4 an d 22.7 Hz. The iso-frequency map was prepared by using natural neighbour interpolation algorithm. For soil-structure resonance assessment we considered large building stock from different Slovenian towns, because the building typology is similar in wider area. Low-rise masonry family houses with two or three floors prev ail. By microtremor measurements inside 45 such buildings their fundamental longitudinal and transver se frequencies were determined and statistically analysed in a complementary study. To assess the possible occurrence of soil-structure resonance in general, the average fundamental frequency +/- one standard devia tion interval is obtained for these two building heights, which give s the range 5.6-11.1 Hz. The free-field microtremor data shows that this frequency range occupies 37% of the urban area in the Litija basin. This study has shown that soil-structure resonance issue for low-rise buildings is frequently overlooked, but should be considere d seriously in shallow sedimentary basins, characterized by relatively high free-field frequencies, because many towns are located in such geological environment., a2_Second application of the derived iso-frequency map is to support soil classification, because recent investigations have shown that fundamental frequency of sediments can be used together with the average shear velocity in the upper 30 m to improve classi fications according to di fferent seismic codes., Andrej Gosar., and Obsahuje bibliografické odkazy
We estimated the common seasonal signal (annual oscillation) included in the Global Positioning System (GPS) vertical position time series by using Multichannel Singular Spectrum Analysis (MSSA). We employed time series from 24 International GNSS Service (IGS) stations located in Europe which contributed to the newest ITRF 2014 (International Terrestrial Reference Frame). The MSSA method has an advantage over the traditional modelling of seasonal signals by the Least-Squares Estimation (LSE) and Singular Spectrum Analysis (SSA) approaches because it can extract time-varying and common seasonal oscillations for stations located in the considered area. Having estimated the annual curve with LSE, we may make a misfit of 3 mm when a peak-to-peak variations of seasonal si gnals are to be estimated due to the time-variability of seasonal signal. A variance of data modelled as annual signal with SSA and MSSA differs of 3 % at average what proves that the MSSA-curves contain only time-varying and common seasonal signal and leave the station-specific part, local phenomena and power-law noise intact. In contrast to MSSA, these effects are modelled by SSA. The differences in spectral indices of power-law noise between MSSA and LSE esti mated with Maximum Likelihood Estimation (MLE) are closer to zero than the ones between SSA and LSE, which means that MSSA curves do not contain site-specific noise as much as the SSA curves do., Marta Gruszczynska, Anna Klos, Severine Rosat and Janusz Bogusz., and Obsahuje bibliografické odkazy
The article deals with geodynamical phenomena of marginal parts of sandstone plateaus. The area of interest consists of several partial areas in the Bohemian Paradise natural reserve. These areas rise above terrain as relics of a once uniform sandstone plateau. The current relief developed mainly in the Pleistocene, when the Jizera River carved present day wide valley and the underlying soft clay rocks were uncovered. Thus favorable conditions were created for slow destruction of sandstone plateaus. Here, the slope movements occur up to the present days in the form of landsliding and slow block movements and their epiphenomena. Due to this continuing activity of the slope movements, human settlements and cultural monuments are endangered. Research in this area helps us to clarify the relation between slope movements and other factors, such as the presence of a significant tectonic failure in the vicinity or the influence of the water regime., Ingrid Forczek., and Obsahuje bibliografii
This paper describes limestone body situated in the northern part of the Branná group near Vápenná village in Javorník area. The body is confined by two major tectonic zones of this area - Sudetic Marginal Fault on the east and Ramzová overthrust on the south. Detailed tectonic analysis has been performed in two big limestone quarries named quarry I and II. Strikes and dips of fault planes and joints were measured. In the quarry I just one important orientation of the fault planes was found - WE mostly vertical. In the quarry II two main fault plane orientations were observed - vertical NW-SE Sudetic and NE-SW Moravo-Silesian. The senses of movements in the fault planes were determined using the calcite steps mainly as the kinematic indicators. Presence of the kinematic indicators allowed performing of paleostress analysis. Several different tectonic phases were identified and discussed., Lucie Nováková., and Obsahuje bibliografii
Based on the analysis performed in the Kura geomorphological sub-region of the Caspian coastal zone, it was determined that the sea level rise of 2.43 m in 1976-1996 caused an average annual rate of erosion processes about 75 times higher than accumulation processes. In 1996-2019, the stabilization and the following drop of the sea level of 1.39 m led to an average annual rate of accumulation processes up to 14 times higher than the average annual rate of erosion processes. This pattern is observed along the entire coastline of those periods. Erosion processes in the initial stage (1976-1996) increased the indentation and length of the coastline by almost 2 times, and in the next stage (1996-2019) the intensification of accumulation processes resulted in the smoothing and reduction of the coastline by 35 %. Statistical analysis of coastlines was carried out by processing Landsat satellite images for 1976-2019; each coastline was divided into 14 segments according to geomorphological zones and their morphostructures in the study area. The development forecast for the next 10 and 20 years is provided., Jeyhun Yashar oglu Gasimov., and Obsahuje bibliografii
We have surveyed the Earth's surface using gravity anomalies and second-order radial derivatives of the disturbing gravitational potential computed from the gravitational model EGM2008 complete to degree and order 2159 (for selected degrees up to 2190). It corresponds to 5 arcmin resolution on the ground. Over most well known impact crater sites on the Earth we found the second-order derivatives (not available from ordinary gravity surveys) offered finer discrimination of circular features than the gravity anomalies themselves. We also discovered that some of the sites show evidence of double or multiple craters which will need further ground verification. Some of these signatures (in hilly or mountainous terrain) may also need to be corrected for the gravitational effect of topography to sharpen their hidden features., Jaroslav Klokočník, Jan Kostelecký, Pavel Novák and Carl A. Wagner., and Obsahuje bibliografii