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In this paper, a study aimed to assess the landslide susceptibility at a regional scale for the wide provincial territory of Matera (Basilicata region, southern Italy) and the relative risk along the main road corridors distributed in this area is presented. A heuristic-bivariate statistical predictive model was performed to assess and map the landslide susceptibility in the study area by using a polynomial function of eight predisposing factors, weighted according to their influence on the instability process. The resulting susceptibility map was successively used for assessing the landslide risk along the provincial road network. The importance of these roads, representing the main network connecting the urban centres, derives from the absence of an efficient integrated transportation system through the entire regional territory. The landslide risk was evaluated through a matricial approach, which has allowed to define the risk levels (low, medium and high) along road stretches by overlapping the consequences and hazard maps, by combining their corresponding classes in a matrix and by associating to each combination a risk level. The resulting landslide risk map provides support information for decision-making and for identifying the priorities for the design of appropriate mitigation plans. [ABSTRACT FROM AUTHOR]

Anthropogenic activities and urbanization frequently spread over areas underlain by unstable karst ground or man-made cavities, leading to potential risk situations for buildings, infrastructure and population. The roof of the cavities may rapidly propagate upwards, eventually resulting in progressive ground settlement and/or sudden collapse. These processes are frequently accelerated or triggered by various human activities (e.g., overloading, water recharge, water table decline). In this paper, the susceptibility to instability of artificial cavity networks under an urban area in Apulia Region, Southern Italy, was assessed and evaluated. Here, there is dense network of underground quarries excavated for the extraction of massive calcarenite for building and ornamental stone that are currently affected by severe instability problems. Identifying the zones of the cavities most prone to instability is of great practical importance. Susceptibility models have been developed analyzing the statistical relationships between the cavity sections with evidence of instability and a number of predisposing factors mainly related to the 3D geometry of the voids, roof thickness and the presence of overloads. The models produced by the discriminant analysis and the logistic regression approaches were independently and quantitatively evaluated through the construction of ROC curves. Although the two models are characterized by different input data treatment, as the logistic regression allows using continuous and discrete variables or any combination of both types even if they do not have a normal distribution, the ROC curves highlighted, for both methods, a satisfactory congruence between the model results and the observed data. Consequently, from the model performance analysis, the two models were evaluated comparable in terms of result reliability. The methodology should be considered as a general first-level analysis for near surface underground cavities aimed at identifying critical cave sectors that can be the focus of more detailed analyses, especially those associated with sensitive zone related to the presence of buildings, roads and frequent presence of human activity. [ABSTRACT FROM AUTHOR]

In this paper, a study aimed to assess the rockfall hazard along a portion of the SS18 coastal road, located in the coastal area of Maratea (Basilicata Region, Southern Italy), is presented. The relevance of this study derives from the location of the study area, because the SS18 is a strategic roads in a touristic area, and, since the hazard assessment was performed in 2004 within a project financed by the Viability Regional Department of Autonomous National Company of Roads (ANAS), from the possibility to validate the results by using real rockfall events occurred after 2004. The procedure for assessing the rockfall hazard was composed of four sequential analyses: (i) geomechanical and kinematic characterization of rock mass, (ii) implementation of Romana's (1985) Slope Mass Rating (SMR) method for identifying the potential boulder release areas (rockfall initiation areas), (iii) determination of rockfall trajectories by using a 3D numerical model (ROTOMAP), (iv) calculation and mapping of the hazard index by combining three factors, i.e., (a) lithological features of outcropping materials on rock faces, (b) kinematic compatibility defined by simulating the rockfall trajectories, and (c) spatial distribution of occurred rockfall events. Finally, the proposed methodology was validated by combining the distribution of the hazard levels along the road with the location on the SS18 of the rockfall events occurred from 2004 to 2014. [ABSTRACT FROM AUTHOR]

A landslide inventory map, which shows the location of landslide phenomena and contains information about movement type, activity, etc., is a basic element for landslide susceptibility and risk assessment. For this reason, the evaluation of the quality, in terms of accuracy and completeness, of landslide inventory maps is an important issue. In this paper, two landslide inventory maps are compared, in order to determine the corresponding quality, through a direct comparison, aimed to evaluate the degree of cartographic matching between the maps, and the determination of the statistical properties of landslide areas and the comparison between the frequency-area statistics of landslides contained in the two inventories. The two landslide inventory maps at 1:25,000 scale, used for these analyses, have been produced for Daunia region (Apulia, Southern Italy), by the Apulia River Basin Authority; the first, 'archive inventory', by unifying the existing archive inventories; the second, 'surveyed inventory', through aerial-photo interpretation and field investigations. [ABSTRACT FROM AUTHOR]

Landslide risk assessment is often a difficult task due to the lack of temporal data on landslides and triggering events (frequency), run-out distance, landslide magnitude and vulnerability. The probability of occurrence of landslides is often very difficult to predict, as well as the expected magnitude of events, due to the limited data availability on past landslide activity. In this paper, a qualitative procedure for assessing the exposure of elements at risk is presented for an area of the Apulia region (Italy) where no temporal information on landslide occurrence is available. Given these limitations in data availability, it was not possible to produce a reliable landslide hazard map and, consequently, a risk map. The qualitative analysis was carried out using the spatial multi-criteria evaluation method in a global information system. A landslide susceptibility composite index map and four asset index maps (physical, social, economic and environmental) were generated separately through a hierarchical procedure of standardising and weighting. The four asset index maps were combined in order to obtain a qualitative weighted assets map, which, combined with the landslide susceptibility composite index map, has provided the final qualitative landslide exposure map. The resulting map represents the spatial distribution of the exposure level in the study area; this information could be used in a preliminary stage of regional planning. In order to demonstrate how such an exposure map could be used in a basic risk assessment, a quantification of the economic losses at municipal level was carried out, and the temporal probability of landslides was estimated, on the basis of the expert knowledge. Although the proposed methodology for the exposure assessment did not consider the landslide run-out and vulnerability quantification, the results obtained allow to rank the municipalities in terms of increasing exposure and risk level and, consequently, to identify the priorities for designing appropriate landslide risk mitigation plans. [ABSTRACT FROM AUTHOR]

The use of satellite Synthetic Aperture Radar Interferometry (InSAR) for monitoring ground instability due to landslide events, although advantageous over large spatial scales, still poses challenges related to the recurrently complex kinematics of the phenomena or to the unfavorable settings of the examined areas with respect to steep topography and vegetated land cover. This paper presents results obtained by using Multi-temporal InSAR techniques with high resolution TerraSARX (TSX) data for monitoring the Carlantino landslide, located in the Daunian Subapennine (Apulia region, southern Italy) on a slope overlooking a water reservoir, and subjected to several investigations and consolidation works. The targets detected by using Persistent Scatterer Interferometry (PSI) correspond to urban structures or peri-urban walls and guard rails, while the landslide body is almost completely devoid of stable targets, due to the widespread vegetation and variable land cover. To allow stability monitoring, a network of six Corner Reflectors (CR) was designed and deployed over the landslide test site. The TSX images were analyzed by using both the PSI processing and a procedure, based on the double difference analysis of InSAR phase values on the CR pixels. Despite residual noise and the loss of 2 CRs due to vandalism, the processing allowed verifying the stability of the upper and central part of the landslide body, and relating indirectly the movements at the toe of the landslide to the water level fluctuations of the reservoir. Finally, this experiment suggests some recommendations and guidelines in planning CR deployment in complex landslide sites. [ABSTRACT FROM AUTHOR]