After the discovery of an archive document regarding an underground crypt beneath the f loors of the Church of St. Margaret (Sv. Marjeta) in Dol pri Ljubljani, Slovenia, further research was carried ...out to confirm its presence. An area filled with construction waste was discovered during a recent small-scale renovation of the church floor. This finding suggested the potential underground chamber may have been partly filled in during one of the previous restorations. A non-invasive GPR study was carried out along eight profiles inside the church to prove the existence of an underground crypt. Results show the presence of an air-filled chamber, confirmed later by a hole drilled in the floor. Additional findings in the church archive and pictures taken by a camera, lowered through a drilled hole, revealed three previously unknown caskets in the crypt. According to the archives, two of them belong to Baron Wolf Daniel Erberg and his wife who died in 1783 and 1774, respectively.
It has been supposed that the Brežice Sava River Terrace (BSRT) is tectonically disturbed near the town of Brežice and tilted to the north. To confirm this tectonically induced tilt in a quantitative ...sense, low-frequency Ground Penetration Radar (GPR) was applied. A total of eight GPR profiles were recorded across the BSRT providing information of the lower boundary of the terrace, which consists of loose to poorly cemented Quaternary gravel, while its Tertiary basement consists of poorly cemented carbonaceous silt (marl). The premise of the study was the assumption that this lithological boundary could be detected by the GPR method. In addition to the upper surface of the BSRT being tilted to the north by 0.18°, GPR profiles also showed a 0.04° difference in the tilt between the upper surface of the terrace and its lower boundary with the basement, which we assigned to the sin-sedimentary tilt. Upon this information, a cumulative tectonically induced dip of the BSRT lower boundary was defined at 0.22
We applied an interdisciplinary approach to analyze the late Quaternary activity of the Sava Fault in the Slovenian Southern Alps. The Sava Fault is an active strike-slip fault, and part of the ...Periadriatic Fault System that accommodated the convergence of Adria and Europe. It is one of the longest faults in the Southern Alps. Using high-resolution digital elevation models from lidar and photogrammetric surveys, we were able to overcome the challenges of assessing fault activity in a region with intense surface processes, dense vegetation, and relatively low fault slip rates. By integrating remote sensing analysis, geomorphological mapping, structural geological investigations, and near-surface geophysics (electrical resistivity tomography and ground penetrating radar), we were able to find subtle geomorphological indicators, detect near-surface deformation, and show distributed surface deformation and a complex fault pattern. Using optically stimulated luminescence dating, we tentatively estimated a slip rate of 1.8 ± 0.4 mm/a for the last 27 ka, which exceeds previous estimates and suggests temporal variability in fault behavior. Our study highlights the importance of modern high-resolution remote sensing techniques and interdisciplinary approaches in detecting tectonic deformation in relatively low-strain rate environments with intense surface processes. We show that slip rates can vary significantly depending on the studied time window. This is a critical piece of information since slip rates are a key input parameter for seismic hazard studies.
vodeAbstractThe Radovna River Valley is located in the north-western part of Slovenia in the Julian Alps, where there is an extensive intergranular aquifer whose depth to pre-Quaternary bedrock is ...unknown. Therefore, to obtain information about the depth of the valley and the geometry of the aquifer two geophysical methods were used in our study; ground penetrating radar (GPR) and seismic reflection method. The low-frequency GPR method has shown to be useful for determining the depth of the groundwater and the predominant groundwater recharge. Also, the high-resolution seismic method provided an insight about the morphology of the pre-Quaternary basement with the deepest point at 141 meters below surface. Measurements of hydrogeological parameters such as groundwater level and river discharge measurements were carried out in the study area. Both data analyses showed that groundwater level and river discharge are highly fluctuating and rapidly changing, indicating a well-permeable aquifer, implying that such an aquifer is extremely sensitive and vulnerable to extreme climate events. Both the geophysical methods and the hydrogeological information have provided important information about the morphology of the valley and the alluvial aquifer, as well as increasing the knowledge about the Radovna springs system, which will contribute very important information for future hydrogeological studies.
In this study, we set up a new drone-borne ground-penetrating radar (GPR) for soil moisture mapping. The whole radar system weighs 1.5 kg and consists of a handheld vector network analyzer (VNA) ...working as frequency domain radar, a lightweight hybrid horn-dipole antenna covering a wide frequency range (250–2800 MHz), a GPS for positioning, a microcomputer with the controlling application, and a smartphone for remote control. Soil moisture is derived from the radar data using full-wave inverse modeling based on the radar equation of Lambot et al. and multilayered media Green's functions. The inversion is performed in the time domain and focuses on the surface reflection. The antenna-drone system is characterized by global reflection and transmission functions which are determined through a calibration procedure. We performed drone-GPR measurements over three different agricultural fields in the loess belt region of Belgium. In this study, we used the 500–700 MHz range to avoid soil surface roughness effects and to focus on the top 10–20 cm of the soil. These fields present a range of landform conditions leading to specific soil moisture distributions. The soil moisture maps were constructed from the local measurements using kriging. The obtained soil moisture maps are in good agreement with the topographical conditions of the fields and aerial orthophotography observations. These results demonstrated the potential and benefits of drone-GPR for fast, high-resolution mapping of soil moisture at the field scale, and to support, e.g., precision agriculture and environmental monitoring.
•We present a new drone-borne ground-penetrating radar (GPR) for soil moisture mapping.•The radar system consists of a lightweight vector analyzer (VNA) combined with a hybrid horn-dipole antenna.•The radar signal is processed using full-wave inversion.•Soil moisture mapping results over 3 test sites demonstrated the protential of the technique.
We evaluated the use of ground penetrating radar (GPR) in detecting karst cavities and discontinuities that could form potential landslide surfaces in flyschoid rocks of the Rodež open pit mine in ...Anhovo (W Slovenia). We recorded 21 GPR profiles in three consecutive benches with the unshielded 50MHz rough terrain antenna (RTA) system, and correlated them with the results of detailed structural and lithological mapping of the area. We located several karst cavities and confirmed the presence of discontinuities with the interpretation of GPR profiles alone. However, their correlation with geological and structural data gave a more precise insight into the structural setting of the studied area. The different discontinuity families specified in the Rodež open pit mine are mainly the result of the strike-slip tectonics and gradual anisotropic lithology. The complexity of the intersections of structural discontinuities and the mechanical properties of rocks contribute to the formation of sliding surfaces and the developing of karst features. Cavities and phreatic channels develop in the vadose zone in calcarenites and result from complex structural deformation and karstification factors at the open joints or larger structural fractures.
•Karst features and sliding surfaces pose a hazard for exploitation in open pit mines.•They were successfully investigated with a low-frequency (50MHz) GPR method.•Correlation with geological mapping gave insight into the structural setting.•Cavities in flyschoid rocks develop at open joints and fractures.•A detailed GPR survey could diminish the possibility of work accidents.
The Karstic thrust edge, a pronounced geomorphologic step, which is a result of the tectonostratigraphic evolution of the active Adria–Dinarides thrust zone, represents a major obstacle for the ...planned new railway route Divača–Koper. Thus, the geotechnical and structural properties as well as the geometry of the thrust-fault planes in this area are of great importance. Since geological mapping cannot give insight into the subsurface to reveal a complex 3D structure, and the numerous boreholes needed to investigate the area would be too expensive and time consuming, the application of a geophysical method such as ground penetrating radar (GPR) is needed. To test the method for determining near surface features and detecting low-angle inclined thrusts, a low frequency GPR system with 50 MHz rough terrain antenna was used to record 13 GPR profiles along all three floors of the Črnotiče quarry, where the spatial position of the Socerb thrust fault that separates limestones above and flysch layers below is relatively well documented. The profiles were positioned across selected existing boreholes. The GPR results were correlated with borehole data as well as geological mapping results. The GPR provided not only precise information on the geometry of the Socerb thrust fault, but was also very useful for establishing the position of some known as well as several potential cavities, both air- and sediment-filled. In areas further from the thrust-fault zone, where the limestone is less tectonically damaged, it was also possible to determine apparent dip angles of the strata, which after reconstruction matched the true dips gathered from geological mapping.
Deciphering deformation mechanisms within Quaternary sediments in a highly dynamic environment such as the southeast European Alps is often a challenging task that requires the use of a variety of ...methods. Due to the geohazards involved, the interpretation of deformation mechanisms can have a major impact on society and may enable the preparation of appropriate engineering solutions. We present an example of how deformation structures can be studied by integrating geomorphological, sedimentological and structural geological mapping using photogrammetric and leveling surveys, paleoseismological techniques, optically stimulated luminescence dating and ground penetrating radar surveys. Quaternary deposits on the slopes of the formerly glaciated Soča Valley near Most na Soči are tilted and dissected along numerous faults within the deformation zone of the Idrija Fault, a large, active, dextral strike-slip fault. Reconstruction of deformation history indicates that at least five deformation events occurred during deposition of the glaciofluvial succession interbedded with glaciolacustrine deposits, dated to Penultimate Glaciation. Ground penetrating radar profiles and outcrop observations reveal NE – SW striking faults, which are approximately perpendicular to the primary Idrija Fault. Based on the local geologic setting, we considered glaciotectonics, gravitational faulting due to ice-decay collapse or slope instability, and tectonic faulting as possible deformation mechanisms. Based on detailed documentation and analysis of the geometry and kinematics of the deformations, we interpret the observed deformations as secondary structures that result from paleoseismic activity of the Idrija Fault, and some structures resulting from glaciotectonics and gravitational faulting. The transtensional type of deformations at the studied site shows the local character of the main fault, which occurs here due to geometrical and kinematical changes of the Idrija Fault causing local transtension in the Most na Soči area. The complexity of the fault and the first paleoseismic evidence dating back to Penultimate Glaciation provide valuable new data for understanding the seismic hazard in the region.
•Origin of deformations within Quaternary sediments in a highly dynamic environment unraveled.•Glaciofluvial and glaciolacustrine deposits record recurrent faulting and non-tectonic deformations.•First paleoseismological evidence on the major Idrija Fault extending back to Penultimate Glaciation.•Local scale fault complexities reflect fault geometric and kinematic changes.
The discovery of written records mentioning an underground crypt beneath the floors of the Church of St. Margaret in Dol pri Ljubljani, Slovenia, lead to further investigations of the area. During a ...small-scale renovation of the church floor, an area filled with construction waste was discovered, suggesting the underground rooms may have been filled in during one of the previous restorations. A GPR study was carried out inside the church in order to determine whether any air-filled chambers were still present beneath the church floor. Results showed the presence of an underground air-filled chamber, the existence of which was confirmed with a small telescopic camera, lowered through a drilled hole in the floor.
The Selo landslide complex in the Vipava Valley (SW Slovenia) is a large fan-shaped sedimentary body that differs significantly from other slope deposits in the area in its exceptional size and ...considerable runout length. The landslide is predominantly composed of carbonate gravel deposited on a flysch paleo-relief. To determine the volume and geometry of the landslide and its potential source area, we integrated geological mapping, ground penetrating radar (GPR) and GIS techniques. The landslide deposits cover an area of about 10 km
2
with an average thickness of 10 m (maximum thickness reaching 56 m) and a maximum length of 5500 m. The volume of carbonate gravel was estimated from geological cross sections and GPR profiles. The base and top surfaces were interpolated by inverse distance and kriging methods, for which the Cut/Fill method was used in ESRI ArcGIS to determine the original landslide volume before the erosion. The estimated original volume is 190 × 10
6
m
3
. The recent volume after the erosion is 96 × 10
6
m
3
. The calculated volume of the Selo landslide, angle of reach θ = 10° and H/L ratio of 0.18 are in accordance with data for landslides of a comparable size. The most reasonable explanation for the development of the Selo landslide complex is a slope collapse involving the breakdown of the rock mass and the development of a high-mobility rock avalanche.
PDF
