Struktur- und Hydrogeologie im Umfeld der Enz-Schwinden bei Holsthum (Südeifel)

Durch verschiedene Tracerversuche ist die hydraulische Verbindung von einer Enz-Schwinde südlich Enzen zur Holsthumer Mühle im Prümtal bewiesen worden. Zahlreiche Schlucklöcher existieren dort, wo der Enzlauf eine markante Störungszone quert und in die klüftigen Dolomitabfolgen des Oberen Muschelkalks eintritt. Die aus verschiedenen Regionen der Trier-Luxemburger Bucht bekannte Verkarstung dieser Schichtenfolge wird dargelegt. Entlang von tektonisch besonders beanspruchten, alt angelegten Schollengrenzen ist die kluftgebundene Verkarstung verstärkt. Vertikale und horizontale Relativbewegungen von Schollen haben zur Zerklüftung des Gebirges nach mehreren Richtungen geführt. Der unterirdische Weg des Grundwassers bis zum Wiederaustritt bei Holsthum wird anhand von Kluftrosen und einer hoch auflösenden Schichtlagerungskarte beschrieben. Der maßgebliche Aquifer ist die Dolomitabfolge der Oberen Ceratitenschichten (mo2C2). Die unterlagernden Tonmergel/Dolomit- Wechselfolgen der Unteren Ceratitenschichten (mo2C1) bilden deren Grundwassersohle. Im Bereich des Untersuchungsgebietes resultierte daraus eine regionale Zweiteilung des vom Oberen Muschelkalk ausgebildeten Oberen Grundwasserstockwerks. Ergebnisse von Brunnenbohrungen bestätigen dies.Abstract: By means of different tracer tests the hydraulic connection between a swallow of the little river Enz south of Enzen and the Holsthum Mill in the Prüm valley has been proven repeatedly. Several swallow holes exist where the Enz crosses a major fault zone and steps into the jointed dolomites of the Upper Muschelkalk. Karstphenomena known from adjacent areas in the Trier-Luxemburg Embayment are described. Along the old tectonic lineaments the joint related karstification has been especially effective. Vertical and horizontal tectonic movements have generated distinct joint sets of different directions. The subterranean water current towards the spring at Holsthum is described by means of joint diagrams and a very detailed subsurface contour map. The most important aquifer layer is the dolomite succession of the Upper Ceratitenschichten (mo2C2). The underlying aquitard is formed by marls and dolomites of the Lower Ceratitenschichten (mo2C1). In the study area a regional division of the subterraneous water system of the Upper Muschelkalk resulted. This fact is confirmed by well data.1. Einleitung 2. Schichtenfolge im Untersuchungsgebiet 3. Tektonik des Untersuchungsgebietes 3.1. Störungen 3.2. Schichtlagerung 3.3. Kluftsysteme 4. Karstphänomene im Oberen Muschelkalk der Trierer Bucht 5. Tracerversuch 6. Geologisch-hydrogeologische Ausdeutung 6.1. Das Verschwinden der Enz-Wässer 6.2. Der unterirdische Fließweg der Wässer 6.3. Der Austritt der Wässer 6.4. Diskussion des Grundwassermodells von Weiler (1991) 6.5. Neue Aspekte zur regionalen Horizontalverschiebungstektonik 7. Ausblick Schriftenresearc

Systematic Quantification and Assessment of Digital Image Correlation Performance for Landslide Monitoring

Accurate and reliable analyses of high-alpine landslide displacement magnitudes and rates are key requirements for current and future alpine early warnings. It has been proved that high spatiotemporal-resolution remote sensing data combined with digital image correlation (DIC) algorithms can accurately monitor ground displacements. DIC algorithms still rely on significant amounts of expert input; there is neither a general mathematical description of type and spatiotemporal resolution of input data nor DIC parameters required for successful landslide detection, accurate characterisation of displacement magnitude and rate, and overall error estimation. This work provides generic formulas estimating appropriate DIC input parameters, drastically reducing the time required for manual input parameter optimisation. We employed the open-source code DIC-FFT using optical remote sensing data acquired between 2014 and 2020 for two landslides in Switzerland to qualitatively and quantitatively show which spatial resolution is required to recognise slope displacements, from satellite images to aerial orthophotos, and how the spatial resolution affects the accuracy of the calculated displacement magnitude and rate. We verified our results by manually tracing geomorphic markers in orthophotos. Here, we show a first generic approach for designing and optimising future remote sensing-based landslide monitoring campaigns to support time-critical applications like early warning systems.ISSN:2076-326

Performance Testing of Optical Flow Time Series Analyses Based on a Fast, High-Alpine Landslide

Accurate remote analyses of high-alpine landslides are a key requirement for future alpine safety. In critical stages of alpine landslide evolution, UAS (unmanned aerial system) data can be employed using image registration to derive ground motion with high temporal and spatial resolution. However, classical area-based algorithms suffer from dynamic surface alterations and their limited velocity range restricts detection, resulting in noise from decorrelation and hindering their application to fast landslides. Here, to reduce these limitations we apply for the first time the optical flow-time series to landslides for the analysis of one of the fastest and most critical debris flow source zones in Austria. The benchmark site Sattelkar (2130–2730 m asl), a steep, high-alpine cirque in Austria, is highly sensitive to rainfall and melt-water events, which led to a 70,000 m³ debris slide event after two days of heavy precipitation in summer 2014. We use a UAS data set of five acquisitions (2018–2020) over a temporal range of three years with 0.16 m spatial resolution. Our new methodology is to employ optical flow for landslide monitoring, which, along with phase correlation, is incorporated into the software IRIS. For performance testing, we compared the two algorithms by applying them to the UAS image stacks to calculate time-series displacement curves and ground motion maps. These maps allow the exact identification of compartments of the complex landslide body and reveal different displacement patterns, with displacement curves reflecting an increased acceleration. Visually traceable boulders in the UAS orthophotos provide independent validation of the methodology applied. Here, we demonstrate that UAS optical flow time series analysis generates a better signal extraction, and thus less noise and a wider observable velocity range—highlighting its applicability for the acceleration of a fast, high-alpine landslide