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Section of Applied Geology, Department Geotechnical Engineering, Federico II University of Naples, Italy
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- PublicationOpen AccessLandslides, volcanism and volcano-tectonics: the fragility of the Neapolitan territory. Cities on Volcanoes 10 Meeting – Napoli 2018(2019)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Small landslides to large debris flows and debris avalanches affected the Neapolitan territory surrounding the active volcanoes of the area: Vesuvius, Campi Flegrei and Ischia. Their variable intensity explosive eruptions produced significant quantities of loose pyroclastic material on the slopes of the volcanoes and of the surrounding reliefs. Remobilization processes of this material occurred during and soon after large explosive eruptions, although their intensity and frequency decreased during inter-eruptive periods. The intensity of these processes varies with the different eruptions and is strongly dependent on availability of fine ash in proximal and distal areas. The areas involved varies from hundreds to millions square meters. The syn-eruptive debris flows of the Vesuvius 472 AD eruption are described in detail. Huge ground uplift of the central part of the Ischia resurgent caldera generated debris/rock avalanches, which likely caused tsunamis. Archaeological sites affected by syn-eruptive debris flows have been selected to show the effects of their deposition. Hydraulic risk and risk mitigation actions, emergency management and preparedness measures will be discussed in one of the areas mostly affected by recent debris flows. At Ischia the characteristics of debris/rock avalanches and lahars related to the resurgence and to the reactivation of volcanism will be discussed.883 273 - PublicationOpen AccessApplicazione di una metodologia sistemica per la valutazione della suscettibilità al dissesto dei versanti tufacei del Comune di Napoli(2006)
; ; ; ; ; ;Bellucci Sessa, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Calcatera, D.; Dipartimento di Ingegneria Geotecnica, Università di Napoli Federico II ;Farina, L.; Borsista C.U.G.Ri., Napoli ;Nocerino, D.; Dipartimento di Ingegneria Geotecnica, Università di Napoli Federico II ;Vilardo, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ; ; It is here described a study which deals with the analysis of landslide susceptibility related to the tuff slopes in Naples, Italy. This type of instability has an important role in the hydro-geological emergencies which affected the city both in historical times and in recent years. The developed GIS algorithm is based on a system model, named RES (Rock Engineering Systems – Hudson, 1992), which accounts for the interactions among the factors involved into the analysed system. Survey campaigns and in situ tests have been carried up to collect the data necessary to allow the characterization of rock masses using classification methods recognized by the International Society of Rock Mechanics. Finally, using the RES a landslide susceptibility index has been estimated for the tuff slopes, which allowed to create the related map. The work here illustrated is part of a larger framework which aim is to create an Integrated Geographic Information System to study the hydro-geological risk in Naples’ territory. This System, hopefully enriched with new thematic layers, while providing the basis for future researches in the field, can also provide local decision-makers and community planners with the scientific and technological support for decisions involving management of risks and urban development.226 545 - PublicationOpen AccessThe glacial traces in the «parco Nazionale d 'A bruzzo » area (Central Apennines): Preliminary note(1990)
; ; ; ; ; ; ; ; ; ; ;In the mountainous area of the «Parco Nazionale d' Abruzzo », characterized by several massifs with maximum altitudes frequently above the 2 000 m, a large number of glacial traces can be observed. The examination of new evidence discovered and the re -examination of those already known has permitted to reconstruct several distinct glacial events. In the studied area the cirques are the most frequent forms due to glacial modelling, even though other glacial remains like troughs and moraine deposits are found in association with them. In a number of places the existence of several episods of glaciation is provided by the occurence of a cirque stairway observed on the same slope. Starting from the more complete and best preserved local sequence an attempt was made to put into order all the other glacial traces. Correlations have been based on relative position and morphology of the cirques and the snow limits. As a result, it seemed likely to refer the observed evidence to four distinct events of glaciation. The first glacial event (pre -wiirmian glaciation, probably Riss) is characterized by a snow limit situated about 1 340 meters a.s.l, and evidenced by few glacial forms in the massifs of Toppe del Tesoro, S. Nicola and the Meta Mountains. They consist of large badly preserved cirque-like depressions situated about 1 300-1 400 meters a.s.l., and moraine deposits whose position and distribution largely contrasts with the actual orographic configuration. During a new glacial advance (maximum wiirrnian expansion) the snow limit rised to 1 560 m. Numerous are the traces relative to this ad vance, consisting in a large number of erosional forms , like cirques and glacial troughs, and morainic deposits which frequently preserve their ori ginal morphology forming lateral and frontal moraines. The third event (first late Wiirmian stage = first apenninic stage of FEDERICI, 1979) is characterized by a further rise of the snow limit now situated about 1 760 m. The evidences rel ative to this minor expansion consist only of erosional forms except one morainic deposit rico gnized on the eastern side of the Meta Mountains. Effects relative to the fourth event (second late Wiirmian stage = second apenninic sta ge of FEDERICI, 1979) can be observed only in the reliefs situated North of the Sangro Valley and in the Meta Mountains, while in the other reliefs the snow limit, situated about 1 970 m, had already reached or passed the altitude of their highest peaks. A summary examination of the distribution and the morphological features of the glacial traces studied shows that the area South of the Sangro valley seems to have developed greater glaciers that the part of the studied area situated at the North of the same valley.82 228 - PublicationRestrictedFrom ERS-1/2 to Sentinel-1: two decades of subsidence monitored through A-DInSAR techniques in the Ravenna area (Italy)(2017-03-30)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ;Land subsidence due to underground resources exploitation is a well-known problem that affects many cities in the world, especially the ones located along the coastal areas where the combined effect of subsidence and sea level rise increases the flooding risk. In this study, 25 years of land subsidence affecting the Municipality of Ravenna (Italy) are monitored using Advanced Differential Interferometric Synthetic Aperture Radar (A-DInSAR) techniques. In particular, the exploitation of the new Sentinel-1A SAR data allowed us to extend the monitoring period till 2016, giving a better understanding of the temporal evolution of the phenomenon in the area. Two statistical approaches are applied to fully exploit the informative potential of the A-DInSAR results in a fast and systematic way. Thanks to the applied analyses, we described the behavior of the subsidence during the monitored period along with the relationship between the occurrence of the displacement and its main driving factors.384 5 - PublicationOpen AccessCapillary Barriers during Rainfall Events in Pyroclastic Deposits of the Vesuvian AreaIn the present paper, the capillary barrier formation at the interface between soil layers, which is characterized by textural discontinuities, has been analyzed. This mechanism has been investigated by means of a finite element model of a two-layer soil stratification. The two considered formations, belonging to the pyroclastic succession of the “Pomici di Base” Plinian eruption (22 ka, Santacroce et al., 2008) of the Somma–Vesuvius volcano, are affected by shallow instability phenomena likely caused by progressive saturation during the rainfall events. This mechanism could be compatible with the formation of capillary barriers at the interface between layers of different grain size distributions during infiltration. One-dimensional infiltration into the stratified soil was parametrically simulated considering rainfall events of increasing intensity and duration. The variations in the suction and degree of saturation over time allowed for the evaluation of stability variations in the layers, which were assumed as part of stratified unsaturated infinite slopes.
487 11 - PublicationOpen AccessTransient infiltration tests in pyroclastic soils with double porosityFallout volcanic deposits of Somma- Vesuvius (Campania, southern Italy), characterized by the presence of layers with contrasting textural and hydraulic properties, are frequently affected by shallow landslides during rainwater infiltration. The soils of the stratigraphic sequence present intra- particle pores, originated by the gases escaped during magma decompression in the volcanic conduit, thus are characterized by double porosity (i.e., intraparticle and interparticle pores), which is expected to affect their hydraulic behaviour, and to play a key role in rainwater infiltration through layered deposits. To understand the effect of double porosity on the hydraulic behaviour of the involved soils, controlled experiments have been carried out in an infiltration column. The experimental apparatus is provided with newly designed non-invasive Time Domain Reflectometry (TDR) probes, not buried in the investigated soil layers so as to minimize disturbance to the flow, allowing water content measurement during vertical flow processes. Specifically, transient flow experiments are carried out through reconstituted specimens of black scoriae and grey pumices, both loose pyroclastic granular soils from fallout deposits of Somma-Vesuvius, featuring double porosity with different pore size distributions, that were estimated by X-ray tomography and Mercury Intrusion Porosimetry. The experimental results highlight the effects of the double porosity and clearly indicate the different behaviour of the two soils during wetting and drying processes, mainly related to the different dimensions of intraparticle pores.
63 3 - PublicationOpen AccessA Combined GNSS-DINSAR-IRT study for the characterization of a deep-seated gravitational slope deformation(2021-11-30)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Large deep-seated gravitational slope deformation (DsGSD) are slope instability phenomena affecting high relief-energy hillslopes and characterized by a high degree of complexity, enhanced also by wideness of the affected area and lithological heterogeneity. A combined approach based on different remote survey methodologies is herein presented with the aim of characterizing one of the most relevant DsGSDs in Sicily (Italy). The Scopello landslide involves the external margin of an overthrust plane, where a rigid carbonate tectonic unit overlies a ductile clayey substratum. The evidence of structural discontinuities crossing the rock masses and of unstable rock mass portions were pointed out by IRT, whose results were combined with the analysis of morphological features retrieved from a DTM, highlighting the presence of regional systems controlling the rock fracturing. Three GNSS surveys have been carried out in 2004 and 2005 on a 27-vertex geodetic network, attesting up to 20cm deformations caused by the triggering of landslides in the substratum. DInSAR results, obtained from the processing and interpretation of ENVISAT and Cosmo-SkyMed images, both in ascending and descending geometry for the time span 2002-2018, allowed evaluating the displacement rates over the area, highlighting that the movement is still active in its upper sector.43 6 - PublicationRestrictedSlope processes in weathered volcaniclastic deposits within the city of Naples: The Camaldoli Hill case(2007)
; ; ; ; ; ; ; ;Calcaterra, D.; Section of Applied Geology, Department Geotechnical Engineering, Federico II University of Naples, Italy ;Coppin, D.; Section of Applied Geology, Department Geotechnical Engineering, Federico II University of Naples, Italy ;De Vita, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Di Vito, M. A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Orsi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Palma, B.; Section of Applied Geology, Department Geotechnical Engineering, Federico II University of Naples, Italy ;Parise, M.; National Research Council, IRPI, Via Amendola 122-I, 70125 Bari, Italy; ; ; ; ; ; We describe the slope processes acting on Camaldoli Hill, the main volcanic feature of the Neapolitan area whose geological evolution and setting have been reconstructed. The backbone of the hill includes the remnants of two partially superposed tuff cones, lying between the Campanian Ignimbrite (CI) and the Neapolitan Yellow Tuff (NYT). This sequence is mantled by pyroclastic, anthropogenic and epiclastic deposits, with abrupt thickness and facies variations. The structural setting of the hill mainly results from several phases of reactivation of the CI caldera faults which were active until about 9.5 ka. Deformation younger than 15 ka is evidenced by landslide deposits, caused by slope instability from volcano-tectonism, and by a high-angle erosional unconformity, formed in response to a base-level lowering. A stratigraphic analysis of the reworked deposits at the foot of the slopes allowed us to define both depositional mechanisms and sedimentation rates. The results of combined volcanological, geomorphological and engineering-geological studies permitted us to constrain and quantify past geological processes and hypothesis about the future evolution of the hill. Present-day slope processes on Camaldoli Hill are largely controlled by the presence of weathered and reworked deposits, whose nature and thickness have been analysed and mapped in detail. Four main kinds of slope processes have been recognized: falls and toppling failures from NYT; small-scale slides in the weathered and pedogenized loose cover; mixed events, represented by slides evolving to hyperconcentrated flows, mud flows and debris flows; and areal and linear erosion. Consequently, a high number of mass movements not previously documented have been mapped. At the same time, an insight into the sedimentation rate due to the overall slope processes, covering a time-span of about 5 ka, was given. Some final considerations regarding landslide hazard are presented in the context of the most suitable remedial works.189 20