Why do some mountain slopes fail catastrophically, while others remain stable for hundreds of thousands of years despite repeated glaciations, earthquakes, and ongoing tectonic activity? The latest research by an international team led by Dr. hab. Jacek Szczygieł from our Institute of Earth Sciences provides new answers to this question. The results have been published in the prestigious journal Engineering Geology.
The study focused on five limestone karst plateaus in the Northern Calcareous Alps of Austria. The researchers used unique geological archives preserved in caves—including deformed speleothems and evidence of passage displacement—to reconstruct the history of gravitational slope deformation over the past approximately 550,000 years. To achieve this, they combined uranium-thorium (U–Th) dating of speleothems, detailed structural analyses, and advanced numerical modelling of stress distribution and slope stability. The results demonstrate that, despite repeated glaciations and episodes of tectonic activity, the investigated mountain massifs have remained remarkably stable. The recorded displacements were minor and never developed into large-scale landslides. The researchers found that this exceptional stability is primarily controlled by the high mechanical strength of the massive Dachstein Limestone, the limited persistence of potential slip surfaces, and an efficient karst drainage system that prevents water pressure from building up within rock fractures.
These findings not only improve our understanding of the long-term evolution of Alpine landscapes but also provide valuable insights for assessing geological hazards and predicting the long-term stability of mountainous regions under changing climatic conditions.
The research was carried out in collaboration between the University of Silesia, the University of Vienna, the Polish Geological Institute – National Research Institute, and the University of Melbourne. The study was supported by the National Science Centre (NCN), Poland, through the SONATA research grant programme.
Szczygieł, J., Dąbrowski, M., Fernandez, O., Hellstrom, J., & Grasemann, B. (2026). Built to last: Long-term stability of steep deglaciated slopes of alpine karst plateaus (Northern Calcareous Alps, Austria). Engineering Geology, 372. https://doi.org/10.1016/j.enggeo.2026.108924
