Gerhard Heiss

Isotopic and Elemental Data for Tracing the Origin of European Olive Oils

H, C, and O stable isotope ratios and the elemental profile of 267 olive oils and 314 surface waters collected from 8 European sites are presented and discussed. The aim of the study was to investigate if olive oils produced in areas with different climatic and geological characteristics could be discriminated on the basis of isotopic and elemental data. The stable isotope ratios of H, C, and O of olive oils and the ratios of H and O of the relevant surface waters correlated to the climatic (mainly temperature) and geographical (mainly latitude and distance from the coast) characteristics of the provenance sites. It was possible to characterize the geological origin of the olive oils by using the content of 14 elements (Mg, K, Ca, V, Mn, Zn, Rb, Sr, Cs, La, Ce, Sm, Eu, U). By combining the 3 isotopic ratios with the 14 elements and applying a multivariate discriminant analysis, a good discrimination between olive oils from 8 European sites was achieved, with 95% of the samples correctly classified into the production site.

Landslide Inventories for Reliable Susceptibility Maps in Lower Austria

Landslide inventories, their accuracy and the stored information are of major importance for landslide susceptibility modelling. Working on the scale of a province (Lower Austria with about 10,000 km2) challenges arise due to data availability and its spatial representation. Furthermore, previous studies on existing landslide inventories showed that only few inventories can be used for statistical susceptibility modelling. In this study two landslide inventories and their resulting susceptibility maps are compared: the Building Ground Register (BGR) of the Geological Survey of Lower Austria and an inventory that was mapped on the basis of a high resolution LiDAR DTM. This analysis was performed to estimate minimum requirements on landslide inventories to allow for deriving reliable susceptibility maps while minimizing mapping efforts. Therefore a consistent landslide inventory once from the BGR and once from the mapping was compiled. Furthermore, a logistic regression model was fitted with randomly selected points of each landslide inventory to compare the resulting maps and validation rates. The resulting landslide susceptibility maps show significant differences regarding their visual and statistical quality. We conclude that the application of randomly selected points in the main scarp of the mapped landslides gives satisfactory results.

Modelling Landslide Susceptibility for a Large Geographical Area Using Weights of Evidence in Lower Austria, Austria

Knowledge of the spatial distribution of landslide susceptibility supports and enhances decision-making involved in land-use planning for mitigating the impacts of landslide hazards. Our study focuses on the application of the weights of evidence (WOE) method to statistically model landslide susceptibility for a large area in the Austrian province of Lower Austria. Approximately 16,000 km2 was modelled with a 10 m × 10 m spatial resolution. To complete this task, a new implementation of WOE in R was developed, a free open source software for statistical computing, to handle the computation of weights for large geospatial datasets. Furthermore, the challenge of modelling diverse landslide conditions for a large area was addressed by modelling WOE separately for each lithology unit. The final susceptibility map was compiled by mosaicking these models. The performances of the models were estimated with a repeated cross-validation approach that measured the area under the receiver operating characteristic curve (AUROC). The results showed good WOE model performances; the median AUROC values ranged from 73 to 93 %, with an average performance of 86 % for the entire study area. Also, this study demonstrated the successful application of WOE for a large geographic area with a high spatial resolution.

Analysis of isotopic signals in the Danube River water at Tulln, Austria, based on daily grab samples in 2012

Results of stable isotope measurements (δ2H, δ18O) of daily grab samples, taken from the Danube River at Tulln (river km 1963) during 2012, show seasonal and short-term variations depending on the climatic/hydrological conditions and changes in the catchment area (temperature changes, heavy rains and snow melt processes). Isotope ratios in river water clearly reflect the isotopic composition of precipitation water in the catchment area since evaporation influences play a minor role. Average δ2H and δ18O values in 2012 are−78‰ and−11.0‰, respectively, deuterium excess averages 10‰. The entire variation amounts to 1.8‰ in δ18O and 15‰ in δ2H. Quick changes of the isotopic composition within a few days emphasise the necessity of daily sampling for the investigation of hydrological events, while monthly grab sampling seems sufficient for the investigation of long-term hydro-climatic trends. 3H results show peaks (half-width 1–2 days, up to about 150 TU) exceeding the regional environmental level of about 9 TU, probably due to releases from nuclear power plants.

Susceptibility maps for landslides using different modelling approaches

This study focuses on the comparison of different approaches for landslide susceptibility modelling and is part of the research project “MoNOE” (Method development for landslide susceptibility modelling in Lower Austria). The main objective of the project is to design a method for landslide susceptibility modelling for a large study area. For other objectives of the project we refer to Bell et al. (Proceedings of the 2nd world landslide forum, Rome, 3–7 Oct 2011, this volume). To reach the main objective, the two different statistical models “Weights of Evidence” and “Logistic Regression” are applied and compared. By using nearly the same input data in test areas it is possible to compare the capabilities of both methods. First results of the comparison indicate that in valleys and on south facing slopes the results are quite similar. In contrast, the analysis on north facing slopes shows differences. In the ongoing work the reasons for these differences will be analysed. Furthermore, attention will be paid to finding adequate validation methods for the two modelling approaches.

Landslide Susceptibility Maps for Spatial Planning in Lower Austria

Landslides threaten most parts of the provincial state of Lower Austria and cause damage to agricultural land, forests, infrastructure, settlements and people. Thus, the project “MoNOE” (Method development for landslide susceptibility modelling in Lower Austria) was initiated by the provincial government to tackle these problems and to reduce further damage by landslides. The main aim is to prepare landslide susceptibility maps for slides and rock falls and to implement these maps into the spatial planning strategies of the provincial state.

A Geotechnical Explanation for the Transition from Creep to Slides in the Alpine Foreland

A 5years continuing study of the regional distribution of mass movements in the eastern Styrian Basin in the Austrian alpine foreland indicates that fast mass movements develop preferably on slopes that showed creep processes before. The geotechnical explanation for this observation is that slopes, which experienced deformation by creep over a long period of time, already show a reduced safety factor for the displaced slope material. Therefore slope areas that have experienced deformation by creep are much more vulnerable to heavy precipitation events and evolve into fast moving slides and flows more common than slopes that have not experienced creep before.

Comparing Landslide Mapping from DTM Satellite Derived Data and Field Based Studies of Loess Sediments in Western China

This paper focuses on experiences gained by creating a landslide inventory map for a study area of approx. 850 km2 near the city of Tianshui in Gansu province, Western China. The study area consists of a Loess landscape that is strongly anthropogenic transformed by terraced agriculture and is interspersed by mainly earthquake triggered landslides. Two different approaches were performed to establish an inventory map of landslides: Mapping landslides from field based studies and mapping landslides from a DTM derived from a Pleiades satellite image pair. Pleiades images offer a panchromatic ground sampling distance of 0.5 m which enabled us to create a Digital Terrain Model (DTM) with a resolution of 1.0 m. The methodologies of these two landslide mapping approaches are presented and respective results are compared showing advantages and disadvantages of each approach. One of the main results of the project was to demonstrate the applicability and the effectiveness of DTM mapping in Loess sediments of Western China. In comparison to field mapping, the DTM inventory is at least of equal quality as the field mapped inventory because of its consistency and completeness. DTM mapping is also a much more cost efficient tool, especially when looking at mapping larger areas in remote locations in Western China, as well as those areas which are difficult to access.

Indicators for Earthquake-Induced Soil Slides in the Flatlands of an Alpine Fringe Area

In Austria’s most eastern province Burgenland, an ongoing study of the regional distribution of mass movements has been performed. In this alpine fringe area more than 280 previously unrecognized active mass movements were mapped, most of them are identified as creep or soil slides. We assume that the majority of these landslides were triggered by intense rainfall, but we also found strong indications that at least two large scale movements might be earthquake-induced. These two movements, each covering an area of more than 1 km2, are situated in the north of the province. In other parts of the province the dimension of mapped landslides averages only 0.03 km2. Compared to the other areas, the hill slopes in the north have the lowest steepness and the lowest annual precipitation. Underground geologic conditions, however, are overall comparable. Earthquakes are only documented in the north of the province and they could have acted as additional trigger for these comparatively large scale landslides with their noticeable different pattern in dimension and volume.