Significant parameters of a landslide dam inventory from the stability assessment aspect - data analysis based on the 'part of the Eastern Alps' data inventory

Landslide dams are counted as one of the most destructive mountain hazards. They pose flood hazards downstream and damming effects upstream. Assessing their stability requires either a detailed case study or relying on geomorphic indices. A case-study project, while being accurate, is time-consuming and cannot be implemented during emergencies. Therefore, geomorphic indices which are calibrated based on the landslide dam inventories facilitate the stability assessment of these dams.

Landslide dam inventories generally include qualitative and quantitative parameters of geographical location, landslide, dam, lake, and upstream catchment. In the current research, a comparison is made on the applicability of the existing geomorphic indices on a developed data inventory of Western Austria, Bavaria, and Northern Italy. The comparison indicates that the geometrical parameters can solely or in combination with each other stand as resisting and driving forces and that the stability assessment based on these parameters is reliable. According to the results, the volume and height of the dam are the most representative parameters of the dam's stability. However, the catchment characteristics such as area, slope, and ruggedness act as the determining destructive force. To evaluate the reliability of the methods used in the calculation or estimation of the geometric parameters, a statistical assessment is conducted based on the data from other published inventories. A wide range of variations in the mean value of the landslide and dam volume indicates the results' dependency on the study areas' geomorphological characteristics. On the other hand, the dam height of the current dataset, the datasets of Japan, New Zealand, and a worldwide database varies in only a 15 m range indicating a close estimation in different geographical regions. This emphasizes the necessity of the existence of a determining procedure for the estimation of such representative parameters in the landslide dam inventories.