Zoning and mapping landslide hazard in the Castelnuovo di Garfagnana region (Tuscany, Italy)

ISPRA (Italian Institute for Environmental Protection and Research) and Tuscany Region Administration recently promoted a research project, aimed at assessing and zoning landslide hazard. The project considered the region of the map n. 250 «Castelnuovo di Garfagnana» (Geological Map of Italy at 1:50,000 scale), mainly including the middle and upper Serchio River basin (Italy). The selected area, about 630 km2 wide, exhibits peculiar geological and geomorphological features, severe climatic conditions (1500-2000 mm of rainfall/year, on average) and high seismicity, which cause widespread landslide hazard for population and facilities. Following a multidisciplinary approach, the data coming from geological, geomorphological and geo-engineering characterization were transformed into GIS-oriented layers and matched with the actual landslide distribution, which was mainly concerned with the most representative landslide types (slide and complex slide-flow movements). Conditional analysis was firstly applied, aiming at evaluating the importance of the considered instability factors. Then an advanced statistical method (Logistic Regression) was applied, to evaluate the effectiveness of the predisposing factors and to provide the hazard ranking of the mapping units. So, the methodology proceeded step by step, as follows: - on site, 1:10,000 scale geomorphological survey, aerial view interpretation and performing of the landslide inventory map; - geo-engineering investigation and in situ and laboratory tests, to analyse physical and mechanical properties of rocks (discontinuity characterization, compression strength, rock mass classification) and soils (grain size, consistency); - organization of the spatial distribution of the considered factors in different layers, each related to a specific factor. The spatial overlay of the layers and their matching with the landslide distribution lead to connections between different instability factors and landslide occurrence; - GIS supported statistical analysis (spatial analysis, conditional and multivariate analyses, neural network technique), so allowing to supply hypothetical connections with an objective and quantitative response; - construction of a final landslide hazard map at 1:50,000 scale. In this map, basing on the stability probability, the landslide hazard is ranked into five classes (very low, low, middle, high and very high hazard). At present, the final map depicts spatially defined landslide susceptibility areas, and no estimate is given about the time of occurrence. The next steps of the research will confront these results with the critical rainfall thresholds for triggering landslides and with the rainfall infiltration models, in order to realise early warning systems and protect population, villages and activities

Zoning and mapping landslide hazard in the Castelnuovo di Garfagnana region (Tuscany, Italy)

ISPRA and Tuscany Region Administration recently funded a project aimed at assessing and mapping landslide hazard of the area of the n. 250 «Castelnuovo di Garfagnana» map (1:50,000 scale). The area includes the upper Serchio River basin (Tuscany, Italy) and exhibits peculiar geological and geomorphological features and severe climatic conditions, which cause high landslide hazard. The project proceeded as follows: 1:10,000 geomorphological survey and landslide inventory map; physical and mechanical properties of rocks (discontinuities, strength, rock mass classification) and soils (grain size, consistency); GIS oriented organization of the spatial distribution of the considered factors; GIS supported statistical analysis (spatial analysis, conditional and multivariate analyses, neural network technique); landslide hazard map, where landslide hazard is subdivided into five classes based on instability probability; final products: landslide hazard map at 1:50,000 scale, together with other related maps (landslide map, structural sketch, geotechnical sketch, isohyet map, etc.); explaining booklet; database

Riverbed and floodplain evolution in the Serchio River basin

The Serchio river basin (about 1600 km2 wide), includes hilly and mountainous areas, where historical towns lie together with industries, factories and tourist facilities, linked by well- developed infrastructures. The geological and geomorphological settings of the basin, the severe climatic conditions favour hydro- geological instability. Frequently heavy and\or relentless rainfall caused the Serchio River and its tributary to overflow, life- threatening and exposing to severe danger towns, resorts, factories and roads. Many landslides occur causing severe damages, high hazard and risk. This situation wholly justifies efforts to improve knowledge of stream dynamics, inundation recurrence and floodplain geomorphological evolution in high risk valley floor areas. Since 2006, the Serchio River Basin Authority (Italian Department of the Environment) has commissioned a LiDAR (Light Detection and Ranging) survey into the valley floor of the Serchio River and along some of its major tributaries, in order to improve knowledge of stream dynamics, to analyse and monitor the territory of jurisdiction. The LiDAR aerial mapping constitutes an innovative and effective instrument for advanced hydrologic and geomorphological assessment. High precision Digital Surface Model (DSM) completed with buildings and vegetation, a filtered DSM obtained by removing vegetation, and a Digital Terrain Model (DTM) derived from the DSM by post-processing, allowed for hydrologic modelling and geomorphological mapping, almost unfeasible by the regional technical map, nor on aerial photos. Multi-temporal aerial photogrammetric analysis was also performed in order to compare the digital model with the photorealistic model and match them together. The outcome of this study is a step forward into hydrologic and geomorphological assessment of floodplain dynamics and evolution., with particular regard to stream erosion activity, flooded areas reconstruction and mapping. Also, the most evident ransformation of the floodplain due to the human activities, such as buildings enlargement, landfill, stores of wasted and\or buildings materials, were identified and monitored

Multidisciplinary investigations in evaluating landslide susceptibility. An example in the Serchio River valley (Italy)

The proposed experimental study is aimed at contributing to the landslide susceptibility evaluation using a multidisciplinary approach: geological, geomorphological and geo-engineering survey, together with multivariate statistical analysis and GIS technique. It is included in a wider research project, aimed at defining the landslide hazard in the area of the map no. 250 ‘‘Castelnuovo di Garfagnana’’ (1:50 000 scale). This study is based on the realization of a landslides inventory map and statistical data analysis using probabilistic methods. The methodology applied in ranking slope instability proceeded step by step. At first, geomorphologic investigation was performed in order to realize a landslide inventory map. A GIS database was created to collect the characteristics related to landslides geometry, type of movement and state of activity. Geo-engineering survey and characterization with in situ and laboratory tests allowed assessing Rock Mass Classification and geotechnical properties of soils (texture and consistency). The statistical approach for evaluating the landslide susceptibility is based on the assumption that the landslide probability for the currently landslides-free areas could be evaluated studying the conditions which led to past and present instability. A set of environmental factors, thought to be related to landslides, were analysed and their spatial distribution organized in different layers. Then, GIS-supported spatial analysis, conditional and multivariate analysis, allowed to calculate the connections between instability factors and landslide distribution. This step evolved towards two distinct statistical methods, both indirect and quantitative, leading to a classification of the land surface in some different susceptibility domains. Conditional analysis was applied to a particular type of terrain unit named Unique Condition Unit (UCU) that is a unique combination of the instability factors. The computer-aided evaluation of the landslide index within each UCU represents the probability of landslide occurrence, according to Bayes statistical concept. Multivariate analysis was applied to the same set of instability factors, but to a different type of terrain unit, the grid cell. The results showed a quantitative response, more reliable about the effectiveness of each instability factors, with the possibility of verifying their statistical significance

CRYSTALS-KYBER

This repository contains the official reference implementation of the Kyber key encapsulation mechanism, and an optimized implementation for x86 CPUs supporting the AVX2 instruction set. Kyber has been selected for standardization in round 3 of the NIST PQC standardization project