A geological 3D-model of Austria

GeoSphere Austria (formerly Geologische Bundesanstalt - Geological Survey of Austria) has produced a supra-regional 3D framework model called “3D AUSTRIA” providing a large-scale geological overview for professional geologists, students and the public. This model is intended to act as support for subsequent regional modelling projects as well as for educational and communicational purpose. The modelled domain of covers a rectangular area of 175 000 km² including the national borders of Austria, down to a depth to 60 km below sea level. Model units are defined following the nomenclature of Schmid et al. (2004) and Froitzheim et al. (2008), each unit having a specific paleo-geographic origin and tectono-metamorphic history. Seven modelling units are considered: two continental plates (1) the Adriatic Plate, (2) the Eurasian Plate, four units from the Alpine orogenic wedge (3) the South-Alpine Superunit, (4) the Austroalpine Superunit, (5) the Penninic Superunit, (6) the Sub-Penninic Superunit and (7) Neogene sedimentary basins in the foreland and within the Alps. Due to the large-scale character of the model, relatively small constituents of the Alpine Orogen are merged together (Meliata Superunit and Inner Western Carpathian Superunit with the Austroalpine Superunit, Helvetic Superunit and Allochtone Molasse with the Sup-Penninic Superunit, intrusive rocks along the Periadriatic Fault with their host unit, minor Neogene basins with the Austroalpine Superunit). The model geometry is constrained by the geological map of Austria 1:1.5M (Schuster et al., 2019), (2) 24 published cross sections and (3) published contour maps for the Moho discontinuity (Ziegler & Dèzes, 2006) and the large Neogene basins. It has been generated with the SKUA-GOCAD software suite following the workflow of Pfleiderer et al. (2016). The framework model 3D AUSTRIA can be visualized with the web 3D Viewer of Geosphere Austria (https://gis.geosphere.at/portal/home/webscene/viewer.html?webscene=c11cd25795294ba8b6f276ab2d072afb) or downloaded from the Tethys Research Data Repository (https://doi.tethys.at/10.24341/tethys.184) allowing the generation of a physical multi-part model using 3D printing technology. It provides a unique way to comprehend the fundamentally 3D nature of sedimentary and tectonic features, like the unconformity at the base of Neogene sedimentary basins, the Alpine frontal thrust or the Tauern Window. The data acquired in the framework of the AlpArray project can be used in future for refining the geometry of 3D AUSTRIA

A new guideline for geological maps with QGIS

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Aerogeophysikalische Daten rund um das Diendorf-Störungssystem

The aerogeophysical dataset contains geomagnetic, electromagnetic and radiometric (Th, U, K) data from five airborne surveys carried out between 1983 and 1997 in the northern part of Lower Austria:Geras (1996, 1997), Pulkau North (1995), Pulkau (1994), Kamptal-Ziersdorf (1983), Krems (1983).The five airborne surveys were conducted with different technical equipment. In 1998, the geomagnetic datasets were combined and reprocessed. The following corrections and reductions have been applied: 1) Normal Field Correction, 2) Heading Error Correction, 3) Reduction to the Pole. In addition, the electromagnetic datasets were also combined and reprocessed. Since reprocessing modern modelling software often includes a reduction to the pole, the magnetic dataset, published here, is corrected, but no reduction-to-the-pole is applied. In 1998 the electromagnetic data sets were also combined and reprocessed. The radiometric data from the five survey sites were combined into one dataset and adjusted to each other in 2009 (using the "levelling" method).The reprocessed data has been reused in two studies: 1) Paoletti et al. (2022) use all five datasets to estimate the location of tectonic faults in 3-dimensional space using software developed at the University of Naples.2) Schattauer et al. (2022) also use all five datasets to test the usability of different GIS tools for rapid interpretation of aerogeophysical data.Detailed description of data acquisition and processing are provided in both mentioned publications and the references therein.Dieser aerogeophysikalische Datensatz beinhaltet geomagnetische, elektromagnetische und radiometrische (Th, U, K) Daten von fünf Helikopterbefliegungen, die zwischen 1983 und 1997 im nördlichen Niederösterreich durchgeführt wurden: Geras (1996, 1997), Pulkau North (1995), Pulkau (1994), Kamptal-Ziersdorf (1983), Krems (1983). Die fünf Aufnahmen erfolgten mit technisch unterschiedlichen Geräten. Daher wurde im Jahr 1998 die einzelnen geomagnetischen Datensätze zusammengefügt und gemeinsam reprozessiert. Folgende Korrekturen und Reduktionen wurden durchgeführt: 1) Normalfeldkorrektur, 2) heading-Fehlerkorrektur, 3) Polreduktion. Da eine Neubearbeitung mit aktueller Modellierungssoftware häufig eine Polreduktion beinhaltet ist hier der korrigierte, aber nicht polreduzierte magnetische Datensatz als Raster publiziert. Auch die elektromagnetischen Datensätze wurden 1998 kombiniert und reprozessiert. Die radiometrischen Daten der fünf Messgebiete wurden 2009 zusammengeführt und aneinander angeglichen (mit der Methode des "Levellings"). Die reprozessierten Daten stehen hier zum Download zur Verfügung und wurden für folgende Studien verwendet:1) Paoletti et al. (2022) verwenden alle fünf Datensätze, um mithilfe von, an der Uni Neapel entwickelter, Software die Lage von tektonischen Störungen im 3-dimensionalen Raum abzuschätzen.2) Schattauer et al. (2022) verwenden ebenso alle fünf Datensätze, um die Anwendung verschiedener GIS-tools für eine schnelle Interpretation von aerogeophysikalischen Daten zu testen.Eine ausführliche Beschreibung der Datenaufnahme und deren Processing sind in beiden Publikationen und den dort erwähnten Referenzen beschrieben.The methods and equipment for acquisition and (re)processing are described in detail in both linked publications (Schattauer et al., 2022, Paoletti et al., 2022) and the references mentioned therein.Die verwendeten Methoden und Ausrüstung für die Aufnahme und für das (Re)processing sind ausführlich in beiden verlinkten Publikationen (Schattauer et al., 2022, Paoletti et al., 2022) sowie in den darin erwähnten Referenzen beschrieben

The Usage of GIS Tools on Vintage Aerogeophysical Data for Simple and Fast Processing with a Focus on Fault Interpretation: An Austrian Case Study

The reuse of vintage datasets which were acquired in the 20th century can pose challenges for modern geophysical modeling due to missing detailed preprocessing information, significant uncertainties, or lack of precise tracking, etc. Nevertheless, they are often the only available datasets in a target region. We explore here the potential of such vintage airborne geophysical datasets (magnetics, AEM, radiometrics) to detect the location and dip direction of geological faults, using a non-modeling interpretation approach based on multiple GIS tools. We apply our approach in a geologically well-known region where four different types of faults are mapped. The applicability of the tools used in this study depend on the geological setting of each fault and is evaluated based on the comparison with geological and—where available—with modeling data. In general, the GIS tools, especially used on a combination of datasets, show reliable results concerning the location and strike of faults, and even seem to be able to predict the dip direction of a fault

Geophysical Study of the Diendorf-Boskovice Fault System (Austria)

We describe here the results of the characterization of subsurface structures in an area of the south-eastern edge of the Bohemian Massif, in Austria by high-resolution geophysical survey techniques and advanced analysis methods of potential fields. The employed methods included potential field multiscale techniques for source-edge location and characterization of sources at depth. Our results confirmed the presence of already known structures: the location of the Diendorf Fault and the Moldanubian Shearzone are clearly recognized in the data at the same location as on the geological maps, even where the Diendorf fault is covered with sediments of the Molasse Basin. In addition, we detected several geological contacts between different rock types in the Bohemian Massif west of the Diendorf Fault. From our results, we were also able to quickly identify and image, without a priori information, previously unknown structures, such as faults with-depth-to-the top of about 500 m and magmatic intrusions about 400 m deep

Implications from palaeoseismological investigations at the Markgrafneusiedl Fault (Vienna Basin, Austria) for seismic hazard assessment

Intraplate regions characterized by low rates of seismicity are challenging for seismic hazard assessment, mainly for two reasons. Firstly, evaluation of historic earthquake catalogues may not reveal all active faults that contribute to regional seismic hazard. Secondly, slip rate determination is limited by sparse geomorphic preservation of slowly moving faults. In the Vienna Basin (Austria), moderate historical seismicity (Imax,obs/Mmax,obs=8/5.2) concentrates along the left-lateral strike-slip Vienna Basin Transfer Fault (VBTF). In contrast, several normal faults branching out from the VBTF show neither historical nor instrumental earthquake records, although geomorphological data indicate Quaternary displacement along those faults. Here, located about 15 km outside of Vienna, the Austrian capital, we present a palaeoseismological dataset of three trenches that cross one of these splay faults, the Markgrafneusiedl Fault (MF), in order to evaluate its seismic potential. Comparing the observations of the different trenches, we found evidence for five to six surface-breaking earthquakes during the last 120 kyr, with the youngest event occurring at around 14 ka. The derived surface displacements lead to magnitude estimates ranging between 6.2±0.5 and 6.8±0.4. Data can be interpreted by two possible slip models, with slip model 1 showing more regular recurrence intervals of about 20–25 kyr between the earthquakes with M≥6.5 and slip model 2 indicating that such earthquakes cluster in two time intervals in the last 120 kyr. Direct correlation between trenches favours slip model 2 as the more plausible option. Trench observations also show that structural and sedimentological records of strong earthquakes with small surface offset have only low preservation potential. Therefore, the earthquake frequency for magnitudes between 6 and 6.5 cannot be constrained by the trenching records. Vertical slip rates of 0.02–0.05 mm a−1 derived from the trenches compare well to geomorphically derived slip rates of 0.02–0.09 mm a−1. Magnitude estimates from fault dimensions suggest that the largest earthquakes observed in the trenches activated the entire fault surface of the MF including the basal detachment that links the normal fault with the VBTF. The most important implications of these palaeoseismological results for seismic hazard assessment are as follows. (1) The MF is an active seismic source, capable of rupturing the surface despite the lack of historical earthquakes. (2) The MF is kinematically and geologically equivalent to a number of other splay faults of the VBTF. It is reasonable to assume that these faults are potential sources of large earthquakes as well. The frequency of strong earthquakes near Vienna is therefore expected to be significantly higher than the earthquake frequency reconstructed for the MF alone. (3) Although rare events, the potential for earthquake magnitudes equal or greater than M=7.0 in the Vienna Basin should be considered in seismic hazard studies.© Author(s) 201