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: 32; Downloads: 3
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2. Not another hillshade: alternatives which improve visualizations of bathymetric dataAna Novak, Sašo Poglajen, Marko Vrabec, 2023, original scientific article Abstract: Increasing awareness of the importance of effective communication of scientific results and concepts, and the need for more accurate mapping and increased feature visibility led to the development of novel approaches to visualization of high-resolution elevation data. While new approaches have routinely been adopted for land elevation data, this does not seem to be the case for the offshore and submerged terrestrial realms. We test the suitability of algorithms provided by the freely-available and user-friendly Relief Visualization Toolbox (RVT) software package for visualizing bathymetric data. We examine the algorithms optimal for visualizing the general bathymetry of a study area, as well as for highlighting specific morphological shapes that are common on the sea-, lake- and riverbed. We show that these algorithms surpass the more conventional analytical hillshading in providing visualizations of bathymetric data richer in details, and foremost, providing a better overview of the morphological features of the studied areas. We demonstrate that the algorithms are efficient regardless of the source data type, depth range, resolution, geographic, and geological setting. The summary of our results and observations can serve as a reference for future users of RVT for displaying bathymetric data.
Keywords: bathymetry, RVT, visualization, hillshade, geomorphology, marine geology, multibeam
Published in DiRROS: 01.12.2023; Views: 206; Downloads: 67
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3. An early glacial maximum during the last glacial cycle on the northern Velebit Mt. (Croatia)Manja Žebre, Mehmet Akif Sarikaya, Uroš Stepišnik, Renato R. Colucci, Cengiz Yildirim, Attila Çiner, Adem Candaş, Igor Vlahović, Bruno Tomljenović, Bojan Matoš, Klaus M. Wilcken, 2021, original scientific article Abstract: Comprehensive glacial Quaternary studies involving geochronological methods, modelling of ice topography with the support of field geomorphological and geological data in the Balkan Peninsula are relatively scarce, although there is evidence of past glaciations in several mountain ranges. Here, we present research on the extent and timing of past glaciations on the northern Velebit Mt. in coastal Croatia and inferences of the climate during that time. Based on geomorphological and sedimentological evidence and using cosmogenic 36Cl surface exposure dating of moraine boulders, we provide an empirical reconstruction of past glaciers and compare this with the Parallel Ice Sheet Model (PISM) simulations under different palaeoclimate forcings. The dating results show that the northern Velebit glaciers reached their maximum extent during the last glacial cycle before the global Last Glacial Maximum (LGM). Maximum ice extent likely correlates with Marine Isotope Stage 5–4, although the exact timing cannot be determined at this point due to poorly known site- and time-specific denudation rates. Empirical reconstruction of the maximum extent suggests that the area covered by glaciers was ~116 km2. The-best fit PISM simulation indicates that the most likely palaeoclimate scenario for the glaciers of this size to form is a cooling of ~8 °C and a 10% reduction in precipitation from present-day levels. However, the best-fit simulation does not correctly model all mapped ice margins when changes in climatological parameters are applied uniformly across the model domain, potentially reflecting a different palaeoprecipitation pattern to today.
Keywords: Pleistocene, cosmogenic isotopes, glacial geomorphology, Dinarides, PISM
Published in DiRROS: 04.03.2022; Views: 640; Downloads: 251
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