Papers by Leonhard Schwarz
Landslides
We introduce and compare two approaches to consistently combine release and runout in GIS-based l... more We introduce and compare two approaches to consistently combine release and runout in GIS-based landslide susceptibility modeling. The computational experiments are conducted on data from the Schnepfau investigation area in western Austria, which include a high-quality landslide inventory and a landslide release susceptibility map. The two proposed methods use a constrained random walk approach for downslope routing of mass points and employ the probability density function (PDF) and the cumulative density function (CDF) of the angles of reach and the travel distances of the observed landslides. The bottom-up approach (A) produces a quantitative spatial probability at the cost of losing the signal of the release susceptibility, whereas the topdown approach (B) retains the signal and performs better, but results in a semi-quantitative score. Approach B also reproduces the observed impact area much better than a pure analysis of landslide release susceptibility. The levels of performance and conservativeness of the model results also strongly depend on the choice of the PDF and CDF (angle of reach, maximum travel distance, or a combination of both).
In recent years several approaches to estimate landslide starting zones were developed. However, ... more In recent years several approaches to estimate landslide starting zones were developed. However, the practical value of the results for hazard assessment cannot be considered proven. The AdaptSlide project provides a comprehensive and conclusive overview of currently available data bases, approaches and models to asses the susceptibility of spontaneous gravitational mass movements in loose material. Approaches to determine the whole affected areas have been developed. Process-orientated geological basic disposition maps, soil maps, remote sensing data, runoff disposition maps and precipitation maps were generated and assessed regarding cost-benefit aspects. The landslide susceptibility of the test-area (communities of Gasen and Haslau in SE_Austria) was modelled with several statistics-based approaches (Neural Network, Weight of Evidence, Logistic Regression) and one deterministic model (SINMAP). Model results have been validated and compared as far as possible; the limitation of cu...
Im vorliegenden Beitrag sollen jene Herausforderungen und Limitierungen erläutert werden, die sic... more Im vorliegenden Beitrag sollen jene Herausforderungen und Limitierungen erläutert werden, die sich im Rahmen der Anwendung Neuronaler Netze für geowissenschaftliche Fragestellungen ergeben. Dies wird am Beispiel der Erstellung einer Rutschungsanfälligkeitskarte der Grunddisposition mittels Neuronaler Netze für die Krisenregion Gasen-Haslau in der Oststeiermark durchgeführt. Im Zuge der Modellanwendung sollte auch getestet werden, wie gut sich Neuronale Netze für die Regionalisierung der Rutschungsdisposition (Rutschungssuszeptibilität) auf Basis einer allgemein verfügbaren Datengrundlage eignen. In der hier untersuchten Region Gasen-Haslau ereigneten sich aufgrund von mehreren aufeinanderfolgenden konvektiven Niederschlag sereignissen mit sehr hohen Tagesniederschlagssummen ab der Nacht vom 21./22. August 2005 mehr als 600 Massenbewegungen.
The Alps are among one of the most beautiful but also most dangerous natural landscapes of Europe... more The Alps are among one of the most beautiful but also most dangerous natural landscapes of Europe. Approximate 70 percent of the Austrian territory are situated in the young and slowly ascending Eastern Alps, where the impact of geomorphological processes, such as gravitational mass movements, often result in catastrophies , causing considerable economical damages and a high number of fatalities. A sustainable protection against mass movements is only possible if stakeholders/decision makers/governments learn from past catastrophes. In August 2005 as well as in June 2009 many regions of Austria were subject to catastrophic flood and mass movement events. The best protection against the consequences of gravitational mass movements is to avoid the construction of buildings and infrastructurewithin susceptible areas. For a reliable susceptibility assessment a high knowledge of past events is of high importance. For this purpose objective and systematic chronicles/registers and document...
In two regions (Gasen-Haslau, Styria, 60 km²; Klingfurth, Lower Austria, 10 km²) with very high p... more In two regions (Gasen-Haslau, Styria, 60 km²; Klingfurth, Lower Austria, 10 km²) with very high process data quality, neural networks and the "simple heuristic GBA Method" (TILCH & SCHWARZ 2010) were used to produce susceptibility maps for spontaneous mass movements in soil (such as soil slips, mud flows). These areas were chosen for study, because a relatively complete landslide inventory exists, based on extensive event documentation in the field and a comprehensive data archive. Due to the high process-data density and the large amount of data, it was possible to progressively reduce the process-data volume. For the Gasen-Haslau region, this was done in the form of percentaged, randomly selected data reduction (to 80%, 60%, 40%, 20%, 10%, 5%, cf. SCHWARZ ET AL. 2009), whereas for the Klingfurth region, the following originator-specific data sets were used: 1. Cadastre of the federal state government of Lower Austria (10 points) 2. Data of the project BUWELA: a comprehen...
In Österreich werden von diversen Institutionen Datenarchive vorgehalten, die Informationen im Ko... more In Österreich werden von diversen Institutionen Datenarchive vorgehalten, die Informationen im Kontext zu gravitativen Massenbewegungen enthalten. Diese sind u.a. aufgrund unterschiedlicher Zielsetzungen und Zuständigkeiten hinsichtlich der Qualität, des Umfangs und regionaler bzw. partieller Vollständigkeit/Zufälligkeit sehr unterschiedlich. Abgesehen davon liegt es in der Natur der Sache, dass die Datenlage (Datenumfang, Datenvollständigkeit) in relativ Rutschung-resistenten und siedlungsarmen Landschaftsräumen nur mäßig sein kann (z.B. Waldviertel), während diese in Rutschunganfälligen und besiedelten Regionen (z.B. Flyschzone) vielerorts, wenn auch nicht flächendeckend, sehr gut ist. Aus dem Gesamtdatensatz generierbare Prozesskataster dienen nicht nur als "Gedächtnis" bisherige Ereignissen, sondern finden auch als Dateninput Einzug in vielerlei Modellrechnungen, beispielsweise zur Erstellung von Prozessdispositionskarten. zu n Je nach der zur Modellierung von Prozessdispositionskarten zur Anwendung kommenden Methode ist der Prozessdatenanspruchs sehr unterschiedlich.
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Papers by Leonhard Schwarz