Roberto Greco

Recent alluvial fans in Calabria (southern Italy)

The present work aims at identifying the location of recent debris-flow-dominated alluvial fans at a regional scale in Calabria (southern Italy). Here, alluvial fans widely occur as both tributary junction and mountain front types and represent a potential hazard to human settlements and transportation links near or on them. The alluvial fans inventory map at 1:250,000 scale was obtained by means of a stereoscopic interpretation of aerial photos shot in 1954–1955. To establish the activity of the detected alluvial fans, recent documentary evidence (scientific reports, local newspapers and journals, and Internet blogs) on debris-flow events and historical satellite imagery available on Google Earth, covering the period 2001–2014, were analysed. Subsequently, the activity of the alluvial fans over the last 60 years has been divided into four classes. A total of 1170 alluvial fans have been mapped, 545 (46.58%) of which have been active over the last 60 years. The alluvial fans with a length from apex to toe < 200 m predominate, constituting 70% of the total. In the feeder basins, the dominant lithologies are represented by medium to high-grade metamorphic rocks and igneous rocks, gravel and debris and, shales and low-grade metamorphic rocks. Finally, the inventory map shows that 103 settlements are located on alluvial fans, 18 of which are active or have been active during the last 60 years. This map is a useful tool for land planning policy and for the assessment of risk deriving from debris-flows on the alluvial fans of the Calabria region.

Landslide-risk scenario of the Costa Viola mountain ridge (Calabria, Southern Italy)

ABSTRACT The study area of the Costa Viola mountain ridge is strongly exposed to shallow landslides triggered by rainfall. Starting from a susceptibility map, recently published by the same team, the related risk has been assessed, limitedly to landslide sources. The hazard has first been evaluated by considering the recurrence periods of triggering events. Economic value and physical vulnerability of the types of elements at risk have been assumed by considering land-use and the effects of similar events in Southern Italy, respectively. The 1:30,000-scale risk map (Main Map) has been produced by combining the above-mentioned layers. Low risk prevails in the study area, whilst the highest values are concentrated along the coast, where villages and the main infrastructure are located. The expected annual damage exceeds 570 million € (about 68% pertaining to low-risk cells). Risk maps produced through similar simplified geographic information system-based procedures may play a crucial role in accurate land-use planning and effective decision-making.

The Use of Airborne LiDAR Data in Basin-Fan System Monitoring: An Example from Southern Calabria (Italy)

To analyse morphologic and volumetric changes within an active basin-fan system of about 0.250 km2 in Calabria (South Italy), we compare two high-resolution DTMs (50 cm) derived from aerial LiDAR surveys conducted in October 2012 and May 2013. The comparison allowed us to: (i) evaluate the magnitude of erosion-transport-sedimentation processes (ii) identify the extent of an active landslide within the feeder sub-basin, and (iii) confirm the fan, feeder channel and feeder basin dynamics obtained from previous works based on geological and geomorphological field surveys. The results demonstrate that the LiDAR techniques can be a useful tool for the monitoring of geomorphological changes in areas affected by severe erosion and depositional processes.

CM SAKe: A Hydrological Model to Forecasting Landslide Activations

Worldwide, most landslides are generally triggered by rainfalls. In this paper, the hydrological model CM SAKe to forecast the timing of activation of slope movements is described.

Shallow-Landslide Susceptibility in the Costa Viola Mountain Ridge (Italia)

The “Costa Viola” mountain ridge (Calabria) is exposed to severe geo-hydrological risk conditions, especially in the sector between Bagnara Calabra and Scilla. This sector has repeatedly been affected by slope instability events in the past, mainly related to debris slides, rock falls and debris flows.

INFLUENCE OF ABS LOW MOLECULAR WEIGHT SPECIES ON ABS PROPETIES

A commercial ABS has been treated with methanol in a Soxhlet apparatus, at the boiling temperature of the solvent, for various procedures and times, in order to extract from it different amounts of low molecular (MW) weight species, a very important parameter in determining the final properties of PC/ABS blends. Thermal, mechanical, dynamic mechanical, and impact properties have been performed on the obtained samples as a function of the amount of the extracted species. The molten state results seem to be very sensitive to the subtraction of low MW species from the ABS, as shown by the viscosity, increasing with enhancing the extraction extent. The glass transitions, detected by dynamic mechanical tests, show that both SAN and B low MW species are extracted from the ABS. Other low MW additives, such as antioxidants and sta- bilizers, are extracted from the ABS as well, giving rise to degradative effects, particularly effective for the materials undergoing processing treatments for prolonged times at high temperatures (i.e., for large extraction amounts). Tensile performances, at a temperature just below the SAN Tg (100°C), show a sensitive influence of this parameter as well as of the above mentioned degradative effects at such a temperature. Impact properties slowly worsen with increasing low MW extracted amounts, and, for high extraction amounts, they exhibit a brittle behavior.