Combining multi-typologies landslide susceptibility maps: a case study for the Visso area (central Italy)

The research proposes a simple but geomorphologically adequate method to produce a combined landslide susceptibility map. In fact, in a logic of real use, offering type-specific landslide susceptibility maps to land use planners and administration could be not a successful solution. On the other hand, the simple grouping of more types of landslides could be misleading for model calibration considering that the relationships between slope failures and geo-environmental predictors should be conveyed by the abundance of each type of landslide resulting not specific and diagnostic for each typology. In this test, after having produced independent models for flow, slide and complex landslide by exploiting MARS (Multivariate Adaptive Regression Splines) and a set of type-specific geo-environmental variables, a combined landslide susceptibility map was obtained by combining the scores of the three source maps. The combined map was finally validated with a new unknown archive, showing very good performances

Geomorphology of the urban area of Palermo (Italy)

The results of a geomorphological study carried out in the urban area of Palermo are summarized in a thematic map. Field survey, analysis of aerial photographs and topographic maps, consultation of historical documents and maps, stratigraphic and topographic reconstruction from numerous wells and subsoil data, and bibliographic search were performed, in order to display the geomorphological changes produced by man over time in a densely populated area and to define the Anthropocene of the study area. Palermo town rises along large marine terrace surfaces cut by small river valleys and bordered by wide degraded and abandoned coastal cliffs. Over the last 2700 years, this area was affected by remarkable man-made changes to topographic surface and underground, exposing large areas of the city to hydraulic, sinkhole, and landslide risks, and increasing the levels of seismic susceptibility. In light of these results, the produced map is useful for urban planning studies

Geositi nel paesaggio mediterraneo: confronto tra aree costiere maltesi e siciliane.

Le isole maltesi mostrano aspetti geologici, geomorfologici e ambientali comparabili con quelli siciliani che danno luogo alla presenza di elementi paesaggistici ad elevata potenzialit\ue0 turistica, ad oggi non sufficientemente valorizzati. Nell\u2019ambito di un progetto di ricerca internazionale volto alla realizzazione di reti ecologiche transfrontaliere Malta-Sicilia (RE.MA.SI.), sono stati condotti studi sulla valorizzazione, divulgazione e corretta fruizione del patrimonio geologico di alcuni territori di queste due isole. Vengono qui presentati i risultati preliminari che hanno portato all'identificazione e valorizzazione di geositi di interesse geomorfologico, le cui caratteristiche sono state analizzate qualitativamente e quantitativamente, tramite l\u2019applicazione di metodologie gi\ue0 sperimentate a livello internazionale e basate sulla stima del loro valore scientifico, addizionale e di fruibilit\ue0. Sono state analizzate principalmente forme di rilevante interesse scientifico, didattico e paesaggistico, quali morfotipi costieri, evidenze morfologiche di processi gravitativi e di erosione idrica e forme carsiche

Hydrogeological behaviour and geochemical features of waters in evaporite-bearing low-permeability successions: A case study in Southern Sicily, Italy

Knowledge about the hydrogeological behaviour of heterogeneous low-permeability media is an important tool when designing anthropogenic works (e.g., landfills) that could potentially have negative impacts on the environment and on people’s health. The knowledge about the biogeochemical processes in these media could prevent “false positives” when studying groundwater quality and possible contamination caused by anthropogenic activities. In this research, we firstly refined knowledge about the groundwater flow field at a representative site where the groundwater flows within an evaporite-bearing low-permeability succession. Hydraulic measurements and tritium analyses demonstrated the coexistence of relatively brief to very prolonged groundwater pathways. The groundwater is recharged by local precipitation, as demonstrated by stable isotopes investigations. However, relatively deep groundwater is clearly linked to very high tritium content rainwater precipitated during the 1950s and 1960s. The deuterium content of some groundwater samples showed unusual values, explained by the interactions between the groundwater and certain gases (H2S and CH4), the presences of which are linked to sulfate-reducing bacteria and methanogenic archaea detected within the saturated medium through biomolecular investigations in the shallow organic reach clayey deposits. In a wider, methodological context, the present study demonstrates that interdisciplinary approaches provide better knowledge about the behaviour of heterogeneous low-permeability media and the meaning of each data type

A multi-scale regional landslide susceptibility assessment approach: the SUFRA_SICILIA (SUscettibilit\ue0 da FRAna in Sicilia) project

The SUFRA project is based on a three level susceptibility mapping. According to the availability of more detailed data, the three scale for susceptibility mapping are increased respect to the ones suggested by the TIER group to 1:100,000, 1:50,000 and 1:25,000/1:10,000. The mapping levels exploit climatic, soil use (CORINE2009) and seismic informative layers, differentiating in the details of the core data (geology and topography), in the quality and resolution of the landslide inventory and in the modelling approach (Tab. 1). SUFRA_100 is based on a heuristic approach which is applied by processing a geologic layer (produced by ARTA integrating pre-CARG 1:100,000 geologic maps); the DEM exploited are IGMI 250m and the mapping units are 1km side square cells. Models are validated with respect to the PAI LIPs (Landslide Identification Points) which are reclassified adopting a simplified scheme. Output cuts of SUFRA100 will be referred to administrative boundaries (provinces). SUFRA50 is based on statistical analysis of new CARG geologic maps and 20m (ITA2000) - 2m (ATA2007) DEM. The mapping units are 500m and 50m cells, hydrographic and hydro-morphometric units. The landslide inventory is the IFFI2012_LIPs (first level) which is the result of the conversion in IFFI format of the PAI archive, which will be supported by remote landslide mapping (exploiting the ATA2007 aerial photos), according to the IFFI first level approach. Validation of the models will be performed exploiting both random spatial partition and temporal partition methods. Output cuts of SUFRA50 will be based on physiographic (basin) and administrative (municipalities) boundaries. SUFRA10/25 is based on statistical analysis of new CARG geologic maps (remotely and field adapted) and 2m (ATA2007) DEM. The mapping units are the slope units (SLUs) which are derived by further partitioning the hydro-morphometric units so to obtain closed morphodynamic units. The landslide inventories is the IFFI2012 which is the results of a field supported (on focus) landslide remote systematic mapping, according to the IFFI full level approach. Examples of SUFRA_100, SUFRA_50 and SUFRA_10 are presented for some representative key sector of Sicily. First results attest for the feasibility and goodness of the proposed protocol. The SUFRA program aims at enabling the regional governmental administration to cope with landslide prevision, which is the required operational concept in land management and planning. PAI has been a great advance with respect to the \u201cpre-SARNO\u201d conditions, but it is very exposed to fail: it is a blind approach for new activations; it is critically dependent on the quality of the landslide inventories; it cannot project the susceptibility outside the landslide area

The role of formic acid/formate equilibria in the oxidation of formic acid on Pt(111)

[EN] The formic acid oxidation reaction has been studied in concentrated perchloric acid solutions (up to 9.14M (60%)) on the Pt (111) surface to explore the relationships between interfacial properties and kinetics. It is found that, as the concentration of perchloric acid in the supporting electrolyte increases, the current markedly decreases, making it possible to detect adsorbed formate on the surface by voltammetric methods. With the aid of DFT calculations, it is shown that the diminution in current is the result of two opposing factors: the reduction in the concentration of free formate in solution and electrode charge effects which encourage the adsorption of formate in a particular configuration. Additionally, the electrochemical behavior under highly acidic conditions suggests the formation of clathrate structures and emphasizes the relevance of the water structure effect in electrode adsorption processes.This work has been financially supported by the Ministerio de Economia, Industria y Competitividad through the project CTQ2016-76221-P. CBR also thanks his Postdoctoral fellowship to Generalitat Valenciana (APOSTD/2017/010).Busó-Rogero, C.; Ferre-Vilaplana, A.; Herrero, E.; Feliu, JM. (2019). The role of formic acid/formate equilibria in the oxidation of formic acid on Pt(111). Electrochemistry Communications. 98:10-14. https://doi.org/10.1016/j.elecom.2018.11.011S10149

The impedance behavior of the cell Au/HClO₄ · 5.5 H₂O/Au in the temperature range 4.2–300 K

The impedance of the cell Au/HClO4-5.5 H2O/Au was investigated in the frequency range 1 to 105 Hz between 4.2 and 300 K. The analysis of the data enables an evaluation of important electrolyte properties such as conductivity and dielectric constant in a wide range of temperatures, predominantly in the solid state of the electrolyte HClO4-5.5 H2O (Tf = 228 K). The double layer capacity of the gold electrodes was also determined; it shows a qualitatively similar result compared with previous measurements. In the solid state, the ionic conductivity exhibits two distinct activation energies of 0.37 and 0.54 eV corresponding to the two phases present in HClO4-5.5 H2O above and below 170 K. Below 120 K the activation energy becomes very small and tends to zero around 80 K indicating possible tunneling processes in the rigid H2O structure. At about the same temperature the dielectric constant reaches its low temperature limit with a value ϵ∞ ≈ 11 which is considerably higher than the value of pure ice of ϵ∞ ≈ 3

Study of the electrical state of the phase boundary between polyelectrolyte gel and electrolyte solution by measurements of membrane potential and volta potential

The concentration dependence of the membrane potential of a film of a polyelectrolyte gel (Nafion) separating two aqueous KCl solutions is measured. Thus, the range of electrolyte concentrations is determined in which the membrane potential is given by the difference of the two equilibrium potential drops (the “Donnan potentials”) across the phase boundaries between the Nafion film and the electrolyte solutions. The results are compared with the concentration dependence of the Volta potential difference between electrodes coated with the same Nafion matrix and a reference metal (Kelvin's vibrating capacitor plate). For these experiments the coated electrodes are withdrawn under potential control from the electrolytes. It is demonstrated that both experimental approaches yield similar information on the equilibrium Donnan potential across the membrane/electrolyte interface, as long as the electrolyte concentration remains below the fixed-charge concentration. At higher electrolyte concentrations, at which the measured membrane potential includes a diffusion potential developing within the membrane phase, the corresponding Volta potential measurements show a measurable change in the surface dipole potential of the withdrawn membrane surface