1. Revealing subtle active tectonic deformation: integrating lidar, photogrammetry, field mapping, and geophysical surveys to assess the Late Quaternary activity of the Sava Fault (Southern Alps, Slovenia)Petra Jamšek Rupnik, Jure Atanackov, Barbara Horn, Branko Mušič, Marjana Zajc, Christoph Grützner, Kamil Ustaszewski, Sumiko Tsukamoto, Matevž Novak, Blaž Milanič, Anže Markelj, Kristina Ivančič, Ana Novak, Jernej Jež, Manja Žebre, Miloš Bavec, Marko Vrabec, 2024, original scientific article Abstract: 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.
Keywords: active fault, lidar, photogrammetry, tectonic geomorphology, structural geology, geophysics, electrical resistivity tomography, ground penetrating radar, slip rate, Sava Fault
Published in DiRROS: 30.04.2024; Views: 19; Downloads: 3
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2. Investigating peatland stratigraphy and development of the Šijec bog (Slovenia) using near-surface geophysical methodsValentina Pezdir, Teja Čeru, Barbara Horn, Mateja Gosar, 2021, original scientific article Abstract: Owing to their anoxic environment, peatlands play an important role in the preservation of records documenting past atmospheric depositions. To determine past records, data on peat stratigraphy and bog development are needed. Ground penetrating radar (GPR) was used to determine the peat thickness and morphology of the Šijec bog on the Pokljuka plateau in Slovenia, which will serve as a basis for further geochemical studies. Information on the stratigraphy below the peat/clay boundary was acquired by applying electrical resistivity tomography (ERT). The GPR results reveal four depressions within the peat bog, which are separated by elevated ridges. Within the depressions the peat reaches a depth of 6–9 m. The edges of the bog are flat, with peat thickness ranging from 2 to 4 m. The reach of the GPR was complemented with manual peat probing. A comparison of the depths obtained using GPR and the peat probe reveals that the results of both methods correspond well in most locations. The ERT indicated similar peat depths; peat responds with high electrical resistivity. In contrast, clayey sediments with low resistivity are found below the peat. The peat depressions are underlain with larger clayey depressions reaching more than 20 m in thickness and represent lake sediments. The complementary geophysical methods proved to be an efficient approach with which we can delineate the peat morphology and the underlying stratigraphy. Both indicate bog formation from a lake with four deeper depressions, that are separated by glacial deposits. The results presented here show the potential for geophysical methods to infer formational processes in peatlands, showing the presence of a series of isolated basins that later coalesced into a single peat landform. This interpretation is consistent with previous conceptual models from studies in boreal regions.
Keywords: peatland, ground penetrating radar, electrical resistivity tomography, peat probing, peat thickness
Published in DiRROS: 07.07.2022; Views: 585; Downloads: 397
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