Andic soils and catastrophic mudflows in Italy: morphological and hydropedological evidences

In Italy rapid landslides are the most frequently occurring natural disasters and, after earthquakes, cause the highest number of victims. In this contribution we attempt to prove that there exist a tight connection between the presence of a specific soil type, namely andic soils, and the occurrence of the main catastrophic mudflows and debris flows occurred in Italy in the last decades. The study was performed by means of an integrated pedological and hydrological analysis on the detachment crowns of some of the most important catastrophic mudflows and debris flows occurred in Italy in the last decades and involving/evolving surface soils. The results at both regional (Campania) and National (Italy) scale clearly show that despite the large variability of the environmental settings of the studied sites there are indeed some striking homogeneous soil features in the detachment crowns including (i) soil morphology, (ii) andic features ranging from high to moderate, (iii) high water retention throughout a large range of pressure heads. Results seem to reveal clear cause-effect evidences between andic soils and the investigated catastrophic mudflows/debrisflows; this must be related to the unique physical properties of these soils inducing high landslide vulnerability

Applicazione di metodi geofisici di tipo geoelettrico ed elettromagnetico per lo studio della distribuzione spaziale dei suoli

Nell’ultimo decennio la risorsa suolo in Italia è stata oggetto di una crescente attenzione, sia per quanto concerne la comprensione dei meccanismi interni che ne determinano la natura sia per quanto riguarda i suoi rapporti con gli altri elementi che caratterizzano il territorio. I numerosi studi condotti al fine di determinare la variabilità dei suoli hanno sempre riscontrato un’elevata variabilità spaziale dei suoli all’interno delle unità cartografiche della Carta dei Suoli. Attualmente le metodologie standard utilizzate per realizzare le carte pedologiche soffrono di una carenza di informazioni utili a comprendere la variabilità spaziale delle proprietà dei suoli. Il punto di partenza di questo lavoro è basato sulla convinzione che le indagini geofisiche possano colmare, almeno in parte, queste carenze e possano comunque dare un contributo notevole alla problematica qui esposta per essere utilizzate come covariate delle proprietà chimico-fisiche del suolo in indagini a scala aziendale. Tra i metodi geofisici, quelli basati sulle proprietà elettriche risultano essere particolarmente indicati per lo studio dei suoli grazie alle buone relazioni esistenti tra le proprietà chimico-fisiche ed elettriche degli stessi. Sono stati quindi utilizzati il metodo di induzione elettromagnetica, la tomografia elettrica 3D e l'ARP. Per comprendere meglio le relazioni esistenti tra le proprietà chimico-fisiche e quelle elettriche dei suoli si è deciso di utilizzare tre casi studio di interesse aziendale: due nel settore vinicolo (Azienda Ocone, Ponte - BN e Azienda Quintodecimo, Mirabella Eclano - AV) ed una in un areale con diverso uso del suolo (Azienda Sperimentale Improsta, Eboli – SA). In tutti i casi studio interessanti appaiono le correlazioni individuate tra la proprietà elettrica ed alcune proprietà dei suoli quali ad esempio il contenuto d’acqua e la tessitura

In situ temporal and spatial monitoring of the structure of a compacted and cultivated loamy soil by the 2D ERT method

International audienceTemporal and spatial monitoring of soil structural heterogeneity is useful to predict physical changes in soils. Usual methods implemented to characterise soil structure are generally destructive and time-consuming. Further technical solutions are then required to describe rapidly the soil structure without any disturbance. Electrical resistivity tomography (ERT) was proven to be efficient technique for detecting accurately zones with contrasted bulk density. Consequently space and time changes in soil structure might be characterized by ERT. We aimed then at testing this possibility by using the 2D ERT method. We have monitored for 8 months a typical Luvisol by ERT. The soil was initially and locally compacted by a heavy tractor in the objective of creating zones of high bulk density. The studied plot encompassed bare soil and wheat crop. ERT results indicated the soil drying process which occurred in summer and particularly under wheat crop. We show also that electrical resistivity was higher in summer with local zone of very high resistivity probably due to soil cracking

Multi-Sensor Approach Combined with Pedological Investigations to Understand Site-Specific Variability of Soil Properties and Potentially Toxic Elements (PTEs) Content of an Industrial Contaminated Area

A combination of indirect soil investigation by proximal soil sensors (PSS), based on geophysical (ARP, EMI), physical (Cone Index –CI– by ultrasound penetrometry) and spectrometric (γ-rays) techniques, as well as pedological surveys, was applied in the field to assess the spatial variability of soil pollution and physical degradation in an automobile-battery recycling plant in southern Italy. Five homogeneous zones (HZs) were identified by the PSS and characterized by soil profiles. CI measurements and field analysis showed clear features of physical (i.e., soil compaction, massive structure) degradation. XRF in situ (on profiles) analysis using portable equipment (pXRF) showed Pb, Cd and As concentrations exceeding the contamination thresholds provided by the Italian regulation for industrial land use up to 20 or 100 cm of depth. Hence, a validation procedure, based on pXRF field survey, was applied to the PSS approach used for the HZs identification. High consistency was found between the HZs and the PTEs in the most contaminated areas. Significant negative Pearson correlation coefficients were found between γ-rays dose rate and Pb, Cu, Zn, As and Ni; positive ones were found between γ-rays and autochthonous lithogenic elements (V, Ti, Mn, K, Sr, Nb, Zr, Rb, Th), confirming that higher radionuclide activity correlated with lower pollution levels