The Emilian Apennines (Northern Apennines) are among the most landslide-prone areas in Italy, due to the prevalence of weak rocks formations, i.e., arenaceous-pelitic flysch and chaotic mélanges. In the Quaternary, landslide processes have been a major geomorphic factor in shaping the landscape of this area. Indeed, most of the landforms are associated with complex large-scale earthflows, mostly developed after the Last Glacial Maximum (Bertolini et al., 2017). Since these ancient wide bodies have to be considered as active in the actual morphoclimatic conditions, their reactivation represents a potential risk for human settlements and urban management (Bertolini & Pizziolo, 2008). Their identification and localization are essential for both the territorial planning and prevention strategies as well as for the general comprehension of the landscape evolution under climatic changes. In this study we investigated the location, extent and characteristics of the landslides in the Val d’Arda, which is an intensively anthropized landslide-prone area in the Emilian Apennines. We applied traditional geomorphological field mapping together with photointerpretation, remote sensing and the analysis of pre-existing databases developed by regional authorities in order to produce a landslide inventory map. Afterward, we analysed the morphological features and the temporal evolution (along a thirty-year period) of some of these landslides by means of high-resolution photogrammetry and the analysis of historical orthophotos. Our results revealed that the study area is highly diversified in terms of type and extent of mass movement processes. Most of the ancient landslides can be classified as complex slide-flow type, which is characterized by a large crown with a relatively steep slide scarp, a narrower middle flow area and a wide basal toe with low slope inclinations. Some of these landslide bodies experimented partial reactivations during the observed time period and, in some cases, show evidence of retrogressive evolution. Moreover, mass movements also include first-time failures, whose morphogenesis, extent and location is mainly controlled by the lithological context and topography, e.g., shallow landslides, mudflows and soil creep on gentle slopes consisting of tectonized clays (“Argille Scagliose” Auctt.) at lower elevations, as well as rock/debris falls and debris flows on very steep slopes made up of flysch. Landslide dams and barrier lakes have also been observed. Our study illustrates the complexity to map and characterize accurately interwoven landslide processes and their dynamics (in landscapes with high landslide hazard). Further analysis will be carried out in order to investigate landslide susceptibilities and the role of different environmental variables as control factors.
Identification and characterization of landslide processes in a Mediterranean catchment: the Val d’Arda case study (Northern Apennines, Emilia-Romagna, Italy
Manuel La Licata
;Michael Maerker
2022-01-01
Abstract
The Emilian Apennines (Northern Apennines) are among the most landslide-prone areas in Italy, due to the prevalence of weak rocks formations, i.e., arenaceous-pelitic flysch and chaotic mélanges. In the Quaternary, landslide processes have been a major geomorphic factor in shaping the landscape of this area. Indeed, most of the landforms are associated with complex large-scale earthflows, mostly developed after the Last Glacial Maximum (Bertolini et al., 2017). Since these ancient wide bodies have to be considered as active in the actual morphoclimatic conditions, their reactivation represents a potential risk for human settlements and urban management (Bertolini & Pizziolo, 2008). Their identification and localization are essential for both the territorial planning and prevention strategies as well as for the general comprehension of the landscape evolution under climatic changes. In this study we investigated the location, extent and characteristics of the landslides in the Val d’Arda, which is an intensively anthropized landslide-prone area in the Emilian Apennines. We applied traditional geomorphological field mapping together with photointerpretation, remote sensing and the analysis of pre-existing databases developed by regional authorities in order to produce a landslide inventory map. Afterward, we analysed the morphological features and the temporal evolution (along a thirty-year period) of some of these landslides by means of high-resolution photogrammetry and the analysis of historical orthophotos. Our results revealed that the study area is highly diversified in terms of type and extent of mass movement processes. Most of the ancient landslides can be classified as complex slide-flow type, which is characterized by a large crown with a relatively steep slide scarp, a narrower middle flow area and a wide basal toe with low slope inclinations. Some of these landslide bodies experimented partial reactivations during the observed time period and, in some cases, show evidence of retrogressive evolution. Moreover, mass movements also include first-time failures, whose morphogenesis, extent and location is mainly controlled by the lithological context and topography, e.g., shallow landslides, mudflows and soil creep on gentle slopes consisting of tectonized clays (“Argille Scagliose” Auctt.) at lower elevations, as well as rock/debris falls and debris flows on very steep slopes made up of flysch. Landslide dams and barrier lakes have also been observed. Our study illustrates the complexity to map and characterize accurately interwoven landslide processes and their dynamics (in landscapes with high landslide hazard). Further analysis will be carried out in order to investigate landslide susceptibilities and the role of different environmental variables as control factors.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.