Forensic analysis of three permanent landslide observatories in Lower Austria

The complexity and variability of slow-moving landslides require long-term, multi-parameter monitoring rather than short-term assessments to effectively evaluate and mitigate potential hazards. This forensic analysis, which is carried out as part of the PARATUS project, focuses on the Landslide Observatory Lower Austria, a unique setting encompassing three study sites: Hofermühle, Gresten, and Brandstatt. Rather than focusing on specific catastrophic events—which are rare for slow-moving landslides, such as the event at the Hofermühle in 2013—this study emphasizes process understanding and the cumulative impacts of slow events, which, over decades, can significantly shape landscapes and risks.

Landslides, the primary hazard under investigation, rank among the most critical natural hazards worldwide due to their ability to cause significant damage across sectors and landscapes. Triggered by various factors, including intense precipitation and human activities, landslides pose ongoing challenges in Lower Austria, where geological and climatic conditions exacerbate susceptibility. The region covers approximately 19,000 km² and serves as a prime setting for Landslide Observatory Lower Austria´s operations. The three observatories are comparable in terms of geological and climatic contexts, land use, and anthropogenic influences, such as drainage systems, yet differ in their spatial extent, landslide subsystems, and dynamics. This diversity enhances the forensic scope of the analysis, offering insights into distinct landslide behaviors and long-term trends.

The Landslide Observatory Lower Austria employs an array of monitoring methods, including automatic inclinometers, terrestrial laser scanning (TLS), UAV surveys, and piezometers, supplemented by meteorological data. These tools capture data at various spatial and temporal scales, from point-specific measurements to areal assessments, enabling the exploration of surface and subsurface movement dynamics. Slow-moving landslides present a unique opportunity for disaster prevention, as their gradual progression allows for detailed study and modeling.

Building resilience for future events requires a multifaceted approach that addresses both immediate needs and long-term strategies. In response to recent events, efforts have been made to improve the recognition of slow-moving processes and landslides as hazards, garnering more national and federal attention. However, challenges persist, particularly in mitigating physical vulnerabilities such as rebuilding infrastructure in high-risk areas and uncovering historical evidence like the locations of drainage pipes. To reduce future risks and increase resilience, ongoing initiatives focus on comprehensive assessments, proactive measures, and filling crucial knowledge gaps to ensure a more robust understanding of hazards and enhance preparedness for potential future incidents. By synthesizing data and insights from Hofermühle, Gresten, and Brandstatt, this analysis provides a robust foundation for improving landslide management in Lower Austria and beyond.