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Lithological maps contain information about the different lithotypes cropping out in an area. At variance with geological maps, portraying geological formations, lithological maps may differ as a function of their purpose. Here, we describe the preparation of a lithological map of Italy at the 1:100000 scale, obtained from classification of a comprehensive digital database and aimed at describing geomechanical properties. We first obtained the full database, containing about 300 000 georeferenced polygons, from the Italian Geological Survey. We grouped polygons according to a lithological classification by expert analysis of the 5456 original unique descriptions of polygons, following compositional and geomechanical criteria. The procedure resulted in a lithological map with a legend including 19 classes, and it is linked to a database allowing ready interpretation of the classes in geomechanical properties and is amenable to further improvement. The map is mainly intended for statistical and physically based modelling of slope stability assessment and geomorphological and geohydrological modelling. Other possible applications include geoenvironmental studies, evaluation of river chemical composition, and estimation of raw material resources. The dataset is publicly available at 10.1594/PANGAEA.935673 (Bucci et al., 2021). [ABSTRACT FROM AUTHOR]

Lithological maps contain information about the different lithotypes cropping out in an area. At variance with geological maps, portraying geologic formations, lithological maps may differ as a function of their purpose. Here, we describe the preparation of a lithological map of Italy at a scale of 1:100,000, obtained from classification of a comprehensive digital database and aimed at describing geo-mechanical properties. We first obtained the full database, containing about 300,000 geo-referenced polygons, from the Italian geological survey. We grouped polygons according to a lithological classification by expert analysis of the original 5,456 unique descriptions of polygons, following compositional and geo-mechanical criteria. The procedure resulted in a lithological map with a legend including 19 classes, and it is linked to a database allowing ready interpretation of the classes in geo-mechanical properties, and amenable to further improvement. The map is mainly intended for statistical and physically based modelling of slope stability assessment, geo-morphological and geo-hydrological modelling. Other possible applications include geo-environmental studies, evaluation of river chemical composition, estimation of raw material resources. [ABSTRACT FROM AUTHOR]

The dependence of rainfall on elevation has frequently been documented in the scientific literature and may be relevant in Italy, due to the high degree of geographical and morphological heterogeneity of the country. However, a detailed analysis of the spatial variability of short-duration rainfall extremes and their connection to the landforms does not exist. Using a new, comprehensive and position-corrected rainfall extreme dataset (I²-RED), we present a systematic study of the relationship between geomorphological forms and the average of rainfall extremes (index rainfall) across the whole of Italy. We first investigated the dependence of sub-daily rainfall depths on elevation and other landscape indices through univariate and multivariate linear regressions. After analyzing the results, we repeated the analysis on geomorphological subdivisions of Italy. The results of the national-scale regression analysis did not confirm the assumption of elevation being the sole driver of the variability of rainfall extremes. The longitude, latitude, distance from the coastline, morphological obstructions and mean annual rainfall resulted to be significantly related to the index rainfall, and to play different roles for different durations (1- to 24-hours). However, when comparing the results of the best multivariate regression models with univariate regressions for morphological subdivisions, we found that "local" rainfall-topography relationships within the geomorphological subdivisions outperformed the country-wide multiple regressions and offered a reasonable representation of the effect of morphology on rainfall extremes. [ABSTRACT FROM AUTHOR]

Starting on 24th August 2016, Central Italy was struck by a six-month earthquake sequence that caused 303 victims and extensive major damages to urban areas and infrastructures, in some cases entire villages needed complete rebuilding. In this paper we present a map that portrays the overall susceptibility to multiple landslide types and the exposure to landslides of the rural-urban areas of the Castelsantangelo sul Nera Municipality, a typical village of the central Italian Apennine. The map is based on a procedure that ingests geomorphological data and models and groups the individual landslide susceptibility maps in a joint susceptibility and exposure map based on expert-defined criteria. The procedure has been applied to built-up and to undeveloped areas to highlight their exposure and was used as a tool for planning post-seismic reconstruction. We advise that such maps are used also as basic tool for ordinary urban planning. [ABSTRACT FROM AUTHOR]

The use of Remotely Piloted Aircraft Systems (RPASs) in geosciences is often aimed at the acquisition of an image sequence to produce digital models and orthophotographs of the topographic surface. The technology can be applied for rockfall hazard and risk assessment. To study rockfalls, an approach consists in the application of numerical models for the computation of rockfall trajectories. Data required for such models include accurate digital terrain models, location of the instability source areas, and the mechanical properties of the terrain. In this article, we present an analysis of the earthquake-triggered rockfall that occurred along the SP18 in Villanova di Accumoli (Lazio, central Italy) during the 24 August 2016 seismic sequence. A survey with a multicopter was carried out to obtain an accurate surface model of the terrain, the identification and characterization of the source areas and of other instable blocks in areas not accessible in the field. The investigated area extends for 6,500 m² and was covered by 161 photographs that were used to obtain an orthophoto with a ground resolution of 2.5 cm, and a digital surface model with a ground resolution of 20 cm x 20 cm, which was processed and fused with GNSS RTK data. We run the numerical model STONE, using the source areas mapped in the field and adopting a slope threshold to get a map showing the rockfall potential trajectories. Results showed that only the part of the road SP18 hit by the rockfall was exposed to further rockfall impacts. In particular, it was observed that 16% (i.e. 5,108) of the 31,800 simulated trajectories reached or crossed this tract of the road. Based on these data, limited protection measures were suggested. The combined use of RPAS data, fused with ground GPS points, an accurate geomorphological survey, and terrain static and dynamic parameters from the literature, allows fast, low-cost and replicable numerical modelling for emergency response and adoption of proper protection measures. [ABSTRACT FROM AUTHOR]

Automatic subdivision of landscapes into terrain units remains a challenge. Slope-units are terrain units bounded by drainage and divide lines, but their use in hydrological and geomorphological studies is limited because of the lack of reliable software for their automatic delineation. We present the r.slopeunits software for the automatic delineation of slope-units, given a digital elevation model and a few input parameters. We further propose an approach for the selection of optimal parameters controlling the terrain subdivision for landslide susceptibility modelling. We tested the software and the optimization approach in Central Italy, where terrain, landslide, and geo-environmental information was available. The software was capable of capturing the variability of the landscape, and to partition the study area into slope-units suited for landslide susceptibility modelling and zonation. We expect r.slopeunits to be used in different physiographical settings for the production of reliable and reproducible landslide susceptibility zonations. [ABSTRACT FROM AUTHOR]

Potential effects on the stability of slopes due to climate change remains an open issue. Forrainfall induced landslides, the point consists in determining the effects of the projectedchanges in the duration and amounts of rainfall that can initiate slope failures. Weinvestigated the relationship between fine-scale climate projections obtained by downscalingand the expected modifications in landslide occurrence in Central Italy, using a deterministiclandslide model within rainfall events extracted from measured and downscaled precipitationdata. We used rainfall measurements taken by 56 rain gauges in the 9-year period 2003–2011,and the RainFARM technique to generate downscaled synthetic rainfall fields from regionalclimate model projections for the 14- year calibration period 2002–2015, and for the40-year projection period 2010–2049. Downscaled precipitation data for the futurescenario was obtained in RainFARM from WRF RPC4.5 model data. Using a specificalgorithm, we extracted a number of rainfall events, i.e. rainfall periods separated by dryperiods of no or negligible amount of rain, from the measured and the syntheticrainfall series. Out of the many thousands of extracted rainfall events, we selected asubset of 50 representative events from the measured series, and a subset of 50events from the synthetic series for each decadal time period, amounting to a totalof 250 events from the downscaled precipitation data. Then, we used each of theselected rainfall events to force the Transient Rainfall Infiltration and Grid-BasedRegional Slope-Stability Model TRIGRS v. 2.1. We analyzed the results in terms ofvariations in the rainfall thresholds for the possible initiation of landslides, in theprobability distribution of landslide size (area), and in landslide hazard. Analyzingresults in terms of rainfall thresholds and size distributions is a novel approachto investigate the effects of climate change on landslide hazard, which allows tomitigate the uncertainties introduced by the specific modeling chain adopted in thisstudy. Results showed that the downscaled rainfall fields obtained by RainFARM can be used tosingle out rainfall events, and to force the slope stability model. Results further showedthat while the rainfall thresholds for landslide occurrence are expected to changein future scenarios, the probability distribution of landslide areas is not. We inferthat landslide hazard in the study area is expected to change in response to theprojected variations in the rainfall conditions, within the scenario considered in thisstudy. We expect our results to contribute to regional investigations of the expectedimpact of projected climate variations on slope stability conditions and on landslidehazards. [ABSTRACT FROM AUTHOR]