Scientific publications of Thomas Zieher
Matching entries: 0
settings...
AuthorTitleYearJournal/ProceedingsReftypeDOI/URL
Zieher, T., Rutzinger, M., Schneider-Muntau, B., Perzl, F., Leidinger, D., Formayer, H. and Geitner, C. Sensitivity analysis and calibration of a dynamic physically based slope stability model 2017 Natural Hazards and Earth System Sciences
Vol. 17(6), pp. 971-992 
article DOI URL 
Abstract: Physically based modelling of slope stability on a catchment scale is still a challenging task. When applying a physically based model on such a scale (1:10000 to 1:50000), parameters with a high impact on the model result should be calibrated to account for (i) the spatial variability of parameter values, (ii) shortcomings of the selected model, (iii) uncertainties of laboratory tests and field measurements or (iv) parameters that cannot be derived experimentally or measured in the field (e.g. calibration constants). While systematic parameter calibration is a common task in hydrological modelling, this is rarely done using physically based slope stability models. In the present study a dynamic, physically based, coupled hydrological–geomechanical slope stability model is calibrated based on a limited number of laboratory tests and a detailed multitemporal shallow landslide inventory covering two landslide-triggering rainfall events in the Laternser valley, Vorarlberg (Austria). Sensitive parameters are identified based on a local one-at-a-time sensitivity analysis. These parameters (hydraulic conductivity, specific storage, angle of internal friction for effective stress, cohesion for effective stress) are systematically sampled and calibrated for a landslide-triggering rainfall event in August 2005. The identified model ensemble, including 25 "behavioural model runs" with the highest portion of correctly predicted landslides and non-landslides, is then validated with another landslide-triggering rainfall event in May 1999. The identified model ensemble correctly predicts the location and the supposed triggering timing of 73.0% of the observed landslides triggered in August 2005 and 91.5% of the observed landslides triggered in May 1999. Results of the model ensemble driven with raised precipitation input reveal a slight increase in areas potentially affected by slope failure. At the same time, the peak run-off increases more markedly, suggesting that precipitation intensities during the investigated landslide-triggering rainfall events were already close to or above the soil's infiltration capacity.
BibTeX:
@article{Zieher2017c,
  author = {Zieher, T. and Rutzinger, M. and Schneider-Muntau, B. and Perzl, F. and Leidinger, D. and Formayer, H. and Geitner, C.},
  title = {Sensitivity analysis and calibration of a dynamic physically based slope stability model},
  journal = {Natural Hazards and Earth System Sciences},
  year = {2017},
  volume = {17},
  number = {6},
  pages = {971--992},
  url = {https://www.nat-hazards-earth-syst-sci.net/17/971/2017/},
  doi = {http://dx.doi.org/10.5194/nhess-17-971-2017}
}
Zieher, T., Schneider-Muntau, B. and Mergili, M. Are real-world shallow landslides reproducible by physically-based models? Four test cases in the Laternser valley, Vorarlberg (Austria) 2017 Landslides, pp. 1-15  article DOI URL 
Abstract: In contrast to the complex nature of slope failures, physically-based slope stability models rely on simplified representations of landslide geometry. Depending on the modelling approach, landslide geometry is reduced to a slope-parallel layer of infinite length and width (e.g., the infinite slope stability model), a concatenation of rigid bodies (e.g., Janbu's model), or a 3D representation of the slope failure (e.g., Hovland's model). In this paper, the applicability of four slope stability models is tested at four shallow landslide sites where information on soil material and landslide geometry is available. Soil samples were collected in the field for conducting respective laboratory tests. Landslide geometry was extracted from pre- and post-event digital terrain models derived from airborne laser scanning. Results for fully saturated conditions suggest that a more complex representation of landslide geometry leads to increasingly stable conditions as predicted by the respective models. Using the maximum landslide depth and the median slope angle of the sliding surfaces, the infinite slope stability model correctly predicts slope failures for all test sites. Applying a 2D model for the slope failures, only two test sites are predicted to fail while the two other remain stable. Based on 3D models, none of the slope failures are predicted correctly. The differing results may be explained by the stabilizing effects of cohesion in shallower parts of the landslides. These parts are better represented in models which include a more detailed landslide geometry. Hence, comparing the results of the applied models, the infinite slope stability model generally yields a lower factor of safety due to the overestimation of landslide depth and volume. This simple approach is considered feasible for computing a regional overview of slope stability. For the local scale, more detailed studies including comprehensive material sampling and testing as well as regolith depth measurements are necessary.
BibTeX:
@article{Zieher2017b,
  author = {Zieher, Thomas
and Schneider-Muntau, Barbara
and Mergili, Martin}, title = {Are real-world shallow landslides reproducible by physically-based models? Four test cases in the Laternser valley, Vorarlberg (Austria)}, journal = {Landslides}, year = {2017}, pages = {1--15}, url = {http://dx.doi.org/10.1007/s10346-017-0840-9}, doi = {http://dx.doi.org/10.1007/s10346-017-0840-9} }
Zieher, T., Markart, G., Ottowitz, D., Römer, A., Rutzinger, M., Meißl, G. and Geitner, C. Water content dynamics at plot scale--comparison of time-lapse electrical resistivity tomography monitoring and pore pressure modelling 2017 Journal of Hydrology
Vol. 544, pp. 195-209 
article DOI URL 
Abstract: Abstract Physically-based dynamic modelling of shallow landslide susceptibility rests on several assumptions and simplifications. However, the applicability of physically-based models is only rarely tested in the field at the appropriate scale. This paper presents results of a spray irrigation experiment conducted on a plot of 100 m2 on an Alpine slope susceptible to shallow landsliding. Infiltrating precipitation applied at a constant rate (27.5 mm/h for 5.3 h) was monitored by means of 2D time-lapse electrical resistivity tomography, combined with time-domain reflectometry sensors installed at various depths. In addition, regolith characteristics were assessed by dynamic cone penetration tests using a light-weight cone penetrometer. The spray irrigation experiment resulted in a vertically progressing wetting front to a depth of 80–100 cm. Below that, the unconsolidated material was already saturated by rainfall in the previous days. The observed mean resistivity reduction attributed to infiltrating water during irrigation was scaled to pressure head. Mean variations in pore pressure were reproduced by a linear diffusion model also used in physically-based dynamic landslide susceptibility modelling. Sensitive parameters (hydraulic conductivity and specific storage) were tested over selected value ranges and calibrated. Calibrated parameter values are within published and experimentally derived ranges. The results of the comparison of observations and model results suggest that the model is capable of reproducing mean changes of pore pressure at a suitable scale for physically-based modelling of shallow landslide susceptibility. However, small-scale variations in pore pressure that may facilitate the triggering of shallow landslides are not captured by the model.
BibTeX:
@article{Zieher2017a,
  author = {Thomas Zieher and Gerhard Markart and David Ottowitz and Alexander Römer and Martin Rutzinger and Gertraud Meißl and Clemens Geitner},
  title = {Water content dynamics at plot scale--comparison of time-lapse electrical resistivity tomography monitoring and pore pressure modelling},
  journal = {Journal of Hydrology},
  year = {2017},
  volume = {544},
  pages = {195--209},
  url = {http://dx.doi.org/10.1016/j.jhydrol.2016.11.019},
  doi = {http://dx.doi.org/10.1016/j.jhydrol.2016.11.019}
}
Zieher, T., Perzl, F., Gruber, F., Rutzinger, M., Meißl, G. and Geitner, C. Data requirements for the assessment of shallow landslide susceptibility using logistic regression 2016 Landslides and Engineered Slopes. Experience, Theory and Practice, pp. 2139-2146  incollection DOI URL 
Abstract: Shallow landslides are an abundant phenomenon in mountain regions. Since these processes often endanger human living it is important to estimate their spatial occurrence. Hence, various modelling techniques for the area-wide assessment of shallow landslide susceptibility are applied (i.e. heuristic, statistically- and physically-based approaches). Amongst these, statistically-based approaches are based on the assumption that factors promoting landslides in the past will also facilitate landsliding in future. Therefore a shallow landslide inventory for the area of interest including sufficient observations for training and validation of the model as well as a high-quality digital terrain model are prerequisites. With the help of a multi-annual shallow landslide inventory and derivatives of two airborne laser scanning campaigns (i) the optimal spatial resolution of the digital terrain model, (ii) the ideal training-to-validation split and (iii) the minimal number of observed landslides required for the assessment of shallow landslide susceptibility using logistic regression are investigated. Predictors are based on the digital terrain models and comprise slope angle, aspect, minimum and maximum curvature, slope length and topographic wetness index. The objectives are discussed for three study areas in Vorarlberg, Austria. Results of the modelling experiments show best performances using a digital terrain model with a spatial resolution of 5 m and a training-to-validation split of 3:7. Regarding the inventory size at least 150 mapped landslides were necessary to achieve acceptable results. However, it is recommended that at least 400 observed landslide locations at a minimum landslide density of 3 landslides/km² are considered for the statistically-based assessment of shallow landslide susceptibility.
BibTeX:
@incollection{Zieher2016b,
  author = {Zieher, T and Perzl, F and Gruber, FE and Rutzinger, M and Meißl, G and Geitner, C},
  title = {Data requirements for the assessment of shallow landslide susceptibility using logistic regression},
  booktitle = {Landslides and Engineered Slopes. Experience, Theory and Practice},
  publisher = {CRC Press},
  year = {2016},
  pages = {2139--2146},
  url = {http://dx.doi.org/10.1201/b21520-270},
  doi = {http://dx.doi.org/10.1201/b21520-270}
}
Zieher, T., Perzl, F., Rössel, M., Rutzinger, M., Meißl, G., Markart, G. and Geitner, C. A multi-annual landslide inventory for the assessment of shallow landslide susceptibility - Two test cases in Vorarlberg, Austria 2016 Geomorphology
Vol. 259, pp. 40-54 
article DOI URL 
Abstract: Abstract Geomorphological landslide inventories provide crucial input data for any study on the assessment of landslide susceptibility, hazard or risk. Several approaches for assessing landslide susceptibility have been proposed to identify areas particularly vulnerable to this natural hazard. What they have in common is the need for data of observed landslides. Therefore the first step of any study on landslide susceptibility is usually the compilation of a geomorphological landslide inventory using a geographical information system. Recent research has proved the feasibility of orthophoto interpretation for the preparation of an inventory aimed at the delineation of landslides with the use of distinctive signs in the imagery data. In this study a multi-annual landslide inventory focusing on shallow landslides (i.e. translational soil slides of 0-2 m in depth) was compiled for two study areas in Vorarlberg (Austria) from the interpretation of nine orthophoto series. In addition, derivatives of two generations of airborne laser scanning data aided the mapping procedure. Landslide scar areas were delineated on the basis of a high-resolution differential digital terrain model. The derivation of landslide volumes, depths and depth-to-length ratios are discussed. Results show that most mapped landslides meet the definition of a shallow landslide. The inventory therefore provides the data basis for the assessment of shallow landslide susceptibility and allows for the application of various modelling techniques.
BibTeX:
@article{Zieher2016a,
  author = {Thomas Zieher and Frank Perzl and Monika Rössel and Martin Rutzinger and Gertraud Meißl and Gerhard Markart and Clemens Geitner},
  title = {A multi-annual landslide inventory for the assessment of shallow landslide susceptibility - Two test cases in Vorarlberg, Austria},
  journal = {Geomorphology},
  year = {2016},
  volume = {259},
  pages = {40--54},
  url = {http://www.sciencedirect.com/science/article/pii/S0169555X16300344},
  doi = {http://dx.doi.org/10.1016/j.geomorph.2016.02.008}
}
Zieher, T. and Nicolussi, K. Rezente Baumgrenz- und Bestandsdynamik im Lafatschertal (Karwendelgebirge, Tirol) 2015 Innsbrucker Jahresbericht  incollection URL 
BibTeX:
@incollection{Zieher2015,
  author = {Zieher, T. and Nicolussi, K.},
  title = {Rezente Baumgrenz- und Bestandsdynamik im Lafatschertal (Karwendelgebirge, Tirol)},
  booktitle = {Innsbrucker Jahresbericht},
  publisher = {Innsbrucker Geographischen Gesellschaft},
  year = {2015},
  url = {http://zieher.cc/publications/pdf/zieher_nicolussi_2015.pdf}
}
Zieher, T. Rezente Dynamik der Baum- und Waldgrenze im Lafatschertal (Karwendelgebirge), Tirol, Österreich 2013 School: University of Innsbruck, Institute for Geography  mastersthesis URL 
BibTeX:
@mastersthesis{Zieher2013,
  author = {Zieher, T.},
  title = {Rezente Dynamik der Baum- und Waldgrenze im Lafatschertal (Karwendelgebirge), Tirol, Österreich},
  school = {University of Innsbruck, Institute for Geography},
  year = {2013},
  url = {http://zieher.cc/publications/pdf/zieher_nicolussi_2015.pdf}
}
Zieher, T., Formanek, T., Bremer, M., Meißl, G. and Rutzinger, M. Digital Terrain Model Resolution and its Influence on Estimating the Extent of Rockfall Areas 2012 Transactions In GIS
Vol. 16(5), pp. 691-699 
article DOI  
Abstract: As rockfall can cause a great deal of damage, it is essential to know its spatial propagation. Rockfall models are sensitive to the resolution of input data, i.e. the Digital Terrain Model (DTM) used. Nowadays, high resolution elevation data are available area-wide from airborne laser scanning (ALS). However, rockfall models are designed for analysis on a certain scale, which means that high resolution input might not necessarily improve model results (e.g. for regional scale studies). Our aim is to estimate the reach of rockfall by analysing different input resolutions of an ALS DTM. The presented empiricallybased model, implemented in Python 2.7, is a modified version of the zenital method including an iterative random walk trajectory model, which is designed for rockfall hazard assessment at the regional scale. Trajectories and rockfall probability maps are generated for selected DTM input resolutions. The comparison shows that high resolution DTMs do consider local topography better and thus lead to more realistic results than low resolution DTMs.
BibTeX:
@article{Zieher2012,
  author = {Zieher, T. and Formanek, T. and Bremer, M. and Meißl, G. and Rutzinger, M.},
  title = {Digital Terrain Model Resolution and its Influence on Estimating the Extent of Rockfall Areas},
  journal = {Transactions In GIS},
  year = {2012},
  volume = {16},
  number = {5},
  pages = {691-699},
  doi = {http://dx.doi.org/10.1111/j.1467-9671.2012.01334.x}
}


back to main page