Near Real-time Detection of Mass Movements at an Alpine Scale

The high mountain areas of the Alps are particularly sensitive to rising temperatures as expressed by the well-documented glacier loss. The link between a warming climate and the frequency of large alpine mass movements is, however, less conclusive across the Alps as a whole. Landslide and rockfall inventories are typically limited to a single class of events, localized to a specific region or research objective, available only with large delays or out of date and frequently the data contains considerable observer bias [2]. Automated and near real-time detection of large mass movements using seismic infrastructure networks have been proposed at a national level, e.g. a for Switzerland [1]. Here, a validation mechanism using an expert group of local observers is used to validate detected events post fact. This allows to (i) detect, localize and classify large rockfalls and landslides at a regional level, (ii) reduce observer bias in manually curated catalogs, and (iii) provide first quantitative analysis of events within minutes. For example, for the main collapse of the Birchgletscher/Nesthorn in Blatten CH on May 28th, 2025, the first analysis of Magnitude 3.1 was available at 15:39:37 CEST, merely 14 minutes after the event occurred. 

In this work, we first analyze the events collected and cataloged using seismic detection over the past two decades in Switzerland and bordering regions under the auspices of the Swiss Seismological Service and the Rockfall Mailing List Collaboration. In a second step, we extend this to the whole Alpine Arc with events from national seismic inventories from Switzerland, Italy, Austria, France and Germany, spanning from 1990 to present. We compare this data to catalogs derived from personal observer networks [2], scientific literature, and personal communications. Initial analysis shows that alongside the increasing temperatures and melting glaciers, the number of large mass movements in the Alps has also been rapidly increasing. A clear elevation envelope from 1000 to 4000 m is found to contain almost all of the rockfalls in the Alps and the majority of which occur in areas under permafrost conditions. The joint multi-source inventory is a first step towards a comprehensive and up-to-date statistical analysis of the impacts of climate change on the occurrence of high alpine mass movements in the Alps. 

[1] Kastli, P., Clinton, J., Kraft, T., Diehl, T., and Haslinger, F.: A near-real-time public mass movement catalogue for Switzerland, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19568, https://doi.org/10.5194/egusphere-egu25-19568, 2025.

[2] PERMOS Rockfall Catalog. https://www.permos.ch/data-portal/rock-falls, accessed January 2025.