Spatial modelling of potential rockfall occurrence in Romania using the Weight of Evidence method

Rockfalls are a destructive geo-hazard in steep environments that, due to their specific mobility and unpredictability, can cause material and human damage, even in the case of small rock volumes. The present work aims to apply, for the first time in Romania, a national-scale multi-criteria statistical and geospatial analysis based on the Weight of Evidence method to predict the potential distribution of rockfall occurrence across the country. The study aims to model, map and statistically evaluate the potential occurrence of rockfalls in the Carpathian and Subcarpathian regions of Romania, by using 1,743 rockfall locations and 19 environmental variables considered to be driving forces of the rockfall process. The results revealed that Romania totals > 18,000 km ² suitable for rockfall assessment and almost 1,500 km ² with occurrence potential. Spatially, it was found that the Carpathian Mountains are by far the most exposed region of the country to rockfalls, especially in the Southern Carpathians branch, where many sectors of terrestrial transport infrastructure are vulnerable to this process. Also, the statistical analysis indicated that ecological and topographical factors play major roles in the occurrence and distribution of rockfalls in Romania. The findings proved to be 94% probabilistically accurate, which means that the potential rockfall occurrence map provides a credible overview of this process in Romania. Consequently, the results can serve as a scientific reference framework for governmental or local authorities in their efforts to mitigate the negative effects associated with rockfalls and to support the planning of transport networks across the Carpathian and Subcarpathian regions.