A LIDAR, GIS and basic spatial statistic application for the study of ravine and palaeo-ravine evolution in the upper Vipava valley, SW Slovenia

ArticleinGeomorphology 204:638-645 · January 2014with 268 Reads
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    In the geomorphologic analysis of the Rebrnice area, SW Slovenia, we used a morphometric indicator of surface roughness, which proved to be very useful in the study of the Sveta Magdalena paleo-landslide in the Rebrnice area. For the investigation of the surface roughness on the Sveta Magdalena paleo-landslide and its nearby area, we used two methods in GIS: slope variability and the Terrain Ruggedness Index (TRI). As an input for the analysis of roughness, we used digital elevation models (DEMs) with a resolution of 3 m × 3 m (resampled from 1 m × 1 m cells) obtained by airborne laser scanning. Based on the analysis of the surface roughness we identified typical morphological characteristics that may reflect the mass gravity flow deposition. With the proper visualization (symbology) we can recognize lobate and fan-shaped forms of the bodies, increased roughness at the edges and at the forefront of the sedimentary body, marginal levees at the edges and arcuate levees in the middle part of the sedimentary bodies.
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    The Post-Forum Study Tour following the 4th World Landslide Forum 2017 in Ljubljana (Slovenia) focuses on the variety of landslide forms in Slovenia and its immediate NW surroundings, and the best-known examples of devastating landslides induced by rainfall or earthquakes. They differ in complexity of the both surrounding area and of the particular geological, structural and geotechnical features. Many of the landslides of the Study Tour are characterized by huge volumes and high velocity at the time of activation or development in the debris flow. In addition, to the damage to buildings, the lives of hundreds of people are also endangered; human casualties occur. On the first day, we will observe complex Pleistocene to recent landslides related to the Mesozoic carbonates thrust over folded and tectonically fractured Tertiary siliciclastic flysch in the Vipava Valley (SW Slovenia), serving as the main passage between the Friulian lowland and central Slovenia, and thus also an important corridor connecting Northern Italy to Central Europe. A combination of unfavourable geological conditions and intense short or prolonged rainfall periods leads to the formation of different types of complex landslides, from large-scale deep-seated rotational and translational slides to shallow landslides, slumps and sediment gravity flows in the form of debris or mudflows. The second day of the study tour will be held in the Soča River Valley located in NW Slovenia close to the border with Italy, where the most catastrophic Stože landslide in Slovenia recently caused the deaths of seven people, and the nearby Strug landslide, which is a combination of rockfall, landslide and debris flow. The final day of the Post-Forum Study Tour will start in the Valcanale Valley located across the border between Slovenia and Italy, severely affected by a debris flow in August 2003. The flow caused the deaths of two people, damaged 260 buildings; large amounts of deposits blocked the A23 Highway, covering both lanes. In Carinthia (Austria), about 25 km west of Villach, the Dobrač/Dobratsch multiple scarps of prehistoric and historic rockslides will be observed. Dobratsch is a massive mountain ridge with a length of 17 km and a width of 6 km, characterized by steep rocky walls. The 3-day study tour will conclude with a presentation of the Potoška planina landslide, a slide whose lower part may eventually generate a debris flow and therefore represents a hazard for the inhabitants and for the infrastructure within or near the village of Koroška Bela.
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  • GIS Tutorial II: Spatial Analysis Workbook
    • D W Allen
    Allen, D.W., 2009. GIS Tutorial II: Spatial Analysis Workbook. ESRI Press, Redlands, San Bernardino Country, California.
  • The Karstic region between the Idrijca and Vipava rivers: a contribution to the study of development of the Karst relief. Opera/Academia scientiarum et atrium Slovenica, Classis IV: Historia naturalis et medicina; Institutum geographicum
    • P Habič
    Habič, P., 1968. The Karstic region between the Idrijca and Vipava rivers: a contribution to the study of development of the Karst relief. Opera/Academia scientiarum et atrium Slovenica, Classis IV: Historia naturalis et medicina; Institutum geographicum.Slovenian Academy of Sciences and Arts, Ljubljana.
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    • J Jež
    Jež, J., 2005. Ocena možnosti nastopanja regionalnih plazov na območju Rebrnic nad Vipavsko dolino. (Thesis) University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Geology, Ljubljana, Slovenia (in Slovenian).
  • Sedimentological characteristics of Quaternary deposits of the Rebrnice slope area (SW Slovenia) Knjiga sažetka. znastveni skup Geologija kvartara u Hrvatskoj s međunarodnim sudjelovanjem
    • T Popit
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    Popit, T., Košir, A., Šmuc, A., 2013a. Sedimentological characteristics of Quaternary deposits of the Rebrnice slope area (SW Slovenia). Knjiga sažetka. znastveni skup Geologija kvartara u Hrvatskoj s međunarodnim sudjelovanjem, Zagreb, 21st-23rd March 2013, 3. HAZU, Zagreb.
    • J P Marques De Sá
    Marques de Sá, J.P., 2007. Applied Statistics Using SPSS. STATISTICA, MATLAB and R. Springer-Verlag, Berlin.
  • Geološko-paleontološki nadzor z vidika varstva naravne dediščine na območju trase HC Razdrto-Vipava, km 3.06.6. Paleontološki inštitut Ivana Rakovca
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    Popit, T., Košir, A., Šmuc, A., Črne, A.E., Goričan, Š., Cimerman, F., 2006. Geološko-paleontološki nadzor z vidika varstva naravne dediščine na območju trase HC Razdrto-Vipava, km 3.06.6. Paleontološki inštitut Ivana Rakovca, Znanstvenoraziskovalni center Slovenske akademije znanosti in umetnosti, Ljubljana (in Slovenian).
  • Kvartarni paleoplazovi na Rebrnicah
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    Popit, T., Košir, A., 2010. Kvartarni paleoplazovi na Rebrnicah. In: Košir, A., Horvat, A., Zupan, H.N., Otoničar, B. (Eds.), Povzetki in ekskurzije. Slovenski geološki kongres, Bovec, 16th-18th September 2010. ZRC SAZU, Ljubljana, 3 (in Slovenian).
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    Replicable, pronounced orientation of discoid pebbles (≥8 mm) embedded on surfaces of large (∼10 m3) experimental debris-flow deposits reveals that strongly aligned, imbricate fabric can develop rapidly over short distances in mass flows. Pebble long axes aligned subparallel to deposit margins as well as subparallel to margins of surge waves arrested within the deposits. Pebble alignment exhibited modes both parallel to (a(p)), the primary flow direction; intermediate axes dipped preferentially inward from surge-wave margins (b(i) orientation). Repetitive development of margin-parallel, imbricate fabric distributed across deposit surfaces provides compelling evidence that deposits formed dominantly through progressive incremental accretion rather than through simple en masse emplacement. Pronounced fabric along deposit and arrested surge-wave margins reflects significant grain interaction along flow margins. This sedimentological evidence for significant marginal grain interaction complements theoretical analyses (Iverson, 1997) and other experimental data (Major, 1996; Iverson, 1997) that indicate that resistance along flow margins is an important factor affecting debris-flow deposition. The fabric on the experimental deposits demonstrates that debris flows can develop strongly imbricate particle orientation that mimics fabric developed during fluvial deposition. Particle shape and local stress fields appear to have more control over fabric development than does general depositional process. Other criteria in addition to particle orientation are needed to discriminate mass flow from fluvial gravel deposits and to unravel depositional history.
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    During mapping of the already accomplished Razdrto – Senože~e section of motorway and geologic surveying of construction operations of the trunk road between Razdrto and Vipava in northwestern part of External Dinarides on the southwestern slope of Mt. Nanos, called Rebrnice, a steep NW-SE striking fault was recognized, situated between the Predjama and the Ra{a faults. The fault was named Vipava fault after the Vipava town. An analysis of subrecent gravitational slips at Rebrnice indicates that they were probably associated with the activity of this fault. Unpublished results of a repeated levelling line along the regional road passing across the Vipava fault zone suggest its possible present activity. It would be meaningful to verify this by appropriate geodetic measurements, and to study the actual gravitational slips at Rebrnice. The association between tectonics and gravitational slips in this and in similar extreme cases in the areas of Alps and Dinarides points at the need of complex studying of geologic proceses.