Experiments of Modelling Subaqueous Landslide Susceptibility in Lake Albano of Castel Gandolfo
摘要
Our modelling experiments aim at generating and interpreting the prediction patterns of subaqueous landslides within the Lake Albano maar, a complex volcanic depression located southeast of Rome. These patterns, which assess the possibility of future events, are based on the spatial distribution of historical landslide forms within the lake, analyzed in conjunction with continuous field values derived from high-resolution digital elevation models. To establish the mathematical framework for modelling these spatial patterns, we employed empirical likelihood ratios and utilized a fuzzy set function to integrate the spatial relationships, both in the presence and absence of landslide forms in the study area. In constructing our analysis, we deployed a high-resolution raster database to pinpoint the locations of 42 linear and 23 polygonal subaqueous landslide forms generating a digital elevation raster and deriving six topographic-surface continuous fields: aspect, digital elevation model, slope, curvature, planform, and profile. No additional information was available besides the six conditionally dependent continuous fields. Our modelling approach involved evaluating prediction patterns through sequential exclusions of individual landslide occurrences or groups, generating cross-validations with partial prediction patterns. Following comparisons of relative ranks within the prediction patterns, we conducted uncertainty analyses and geological interpretations to identify critically susceptible areas, particularly the topple scarps and landslide scarps surrounding the lower escarpment of Lake Albano. These features are situated within the context of past lahar deposits and suspected catastrophic floods, such as those documented in 398 BC, which impacted the volcanic crater of Lake Albano during Roman times. It is imperative to recognize the multi-hazard context of this region, which poses serious risks to urbanization, recreational activities, and heritage sites. Despite the reclassification of the volcanic crater from extinct to dormant, the potential for future subaqueous landslides underscores the ongoing need for proactive risk management strategies in the area surrounding Lake Albano.