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Nella guida sono descritti - con un approccio divulgativo scientifico e in dettaglio - gli affioramenti geologici, gli elementi strutturali e gli aspetti geomorfologici dell’Isola di Capri, anche mediante un itinerario via mare e a terra. In particolare, questi aspetti sono illustrati mediante una carta geologica schematica con indicazione dell'itinerario e dei vari stop, nonché sono approfonditi con numerose fotografie degli affioramenti rocciosi e dei fossili, disegni di colonne stratigrafiche e schemi dell’evoluzione morfologica a colori.

Le pocket beach, piccole spiagge confinate tra promontori rocciosi, costituiscono luoghi unici e di elevato valore ambientale. Negli ultimi decenni, in Campania ed in tutta Italia, esse sono state oggetto di un intenso sviluppo turistico che ne sta mettendo a rischio la conservazione. Tutto ciò avviene quando ancora le conoscenze sui processi che regolano la dinamica di queste spiagge sono tutt'altro che approfondite. La disponibilità di un primo quadro nazionale, realizzato con criteri omogenei, consente di evidenziare le criticità che le affliggono e fornisce elementi utili per la loro gestione.

Le pocket beach, piccole spiagge confinate tra promontori rocciosi, costituiscono luoghi unici e di elevato valore ambientale. Negli ultimi decenni, in Campania ed in tutta Italia, esse sono state oggetto di un intenso sviluppo turistico che ne sta mettendo a rischio la conservazione. Tutto ciò avviene quando ancora le conoscenze sui processi che regolano la dinamica di queste spiagge sono tutt'altro che approfondite. La disponibilità di un primo quadro nazionale, realizzato con criteri omogenei, consente di evidenziare le criticità che le affliggono e fornisce elementi utili per la loro gestione.

A significant part of Campania is extensively covered by volcaniclastic soils, deriving from the alteration of airfall-sedimented formations of layered ashes and pumices that were ejected by Campi Flegrei and Mt.Somma-Vesuvius during explosive eruptions. Where such soils cover steep slopes cut in carbonate bedrock, landforms depend essentially on the morpho-evolution of the slopes prior to the deposition of the volcaniclastic soils, because they are generally present only as thin veneers, up to a few meters of total thickness. In this part of Campania, landslides that originate within the volcaniclastic soil veneer "sandwich" lying on carbonate slopes and terminate at their foot or at gully outlets are frequent and often destructive, following critical rainfall events. Such landslides can be classified as complex, occurring initially as debris slides, but rapidly evolving into debris avalanches and/or debris flows. The localization of the initial sliding areas (i.e. "sources") on the slopes depends on both the spatial distribution of characters of the soil cover and the spatial distribution of the triggering rainfall events. It therefore appeared reasonable to separate the two aspects of the problem, and focus on the former one, in order to attempt an assessment of soil sliding susceptibility in the event of landslide-triggering rainfall. Some results of the application of a method aimed at such an assessment are going to be presented. The method, called SL.I.DE. (from SLiding Initiation areas DEtection), is based on the assumption that, in case of spatially homogeneous slide-triggering rainfall sequences and volcaniclastic soil cover, different slope gradient threshold values for sliding failure exist, depending on soil cover continuity and planform curvature. Such threshold values are considered as higher on planar slopes than on slopes with discontinuities within the soil cover, as well as on slopes that display upwards concavity in planform (hollows). The method is indeed geomorphological, but it is also essentially quantitative, as in its workflow only the delineation of soil cover existence, and of discontinuities within it, are subjective. Comparison between past landslides' source areas localization (although available with variable reliability) and SL.I.DE. method susceptibility provided encouraging results, especially regarding soil-covered sloping hollows. Where such a localization was available with adequate accuracy and the number of nearby landslides was large, the method appeared as capable of recognizing most of the actual landslides' source areas. At the same time, the method reasonably overestimated areas considered as susceptible to sliding with respect to actual source areas. Overestimation, however, should be considered as such only with respect to past landslides: areas deemed as susceptible to sliding, but not interested by past landslides, should also be carefully evaluated with respect to the possibility of future landslides. Developments of the method are being pursued, by analyzing slope areas that fall into more than one susceptibility categories. In practical terms, for instance, opening new slope tracks within volcaniclastic soils covering slope hollows at angles > 30° appears inappropriate with respect to rainfall-triggered potential local instability. Assessment of soil sliding susceptibility, while only a subset of the related hazard and risk assessments, can certainly be considered worth investigating, as planners and communities could certainly take advantage from knowledge regarding where landslides can originate in case of critical rainfall. This, together with analyses of potential paths and run-out of debris avalanches/flows, could suggest including also the feasibility of slope stabilization work within evaluations of risk-reduction cost-benefit options, as techniques for the stabilization of soil covers on the slopes are nowadays indeed available.

Il contributo riguarda gli aspetti geologico-applicativi ed idrogeologici del territorio ricadente nel Foglio n. 467 della Carta Geologica d'Italia in scala 1:50.000. Vengono illustrate le frane, le cave e le risorse idriche sotterranee di tale contesto territoriale.

A method for evaluating the susceptibility to debris slides, due to critical rainfall sequences, is discussed. The method concerns the volcaniclastic soils of Campania (Southern Italy) covering carbonatic slopes. It is based on the concept that, for a spatially homogeneous soil cover and a spatially homogeneous triggering rainfall sequence, different values of threshold slope gradient exist for limit equilibrium conditions, depending on the continuity and planform curvature of the soil cover. The method derives from the analysis of the location of the source areas of the landslides originated on May 5, 1998, on the slopes of the Pizzo d’Alvano massif, when more than a hundred of almost contemporary debris slides were triggered, providing a consistent data set. In order to test the potential of the method for the spatial prediction of debris slide triggering also in other areas of Campania displaying similar geomorphology and soil cover, it has first been applied to that same massif to verify, although a posteriori, its ability to assess the sliding susceptibility of the volcaniclastic soils prior to the May 1998 event. Comparison of the sliding susceptibility resulting from the method and the locations of the actual May 5, 1998, landslide source areas provided good results: the susceptible areas, covering 15% of the studied area, overestimated the actual source areas, while 94% of the actual source areas fell into susceptible areas. Accordingly, a simplified version of the method has been applied to a much larger area, historically and also recently struck by debris slides – debris avalanches – debris flows. Although, in this latter case, a comparison of the resulting sliding susceptibility with the locations of actual landslide source areas could be carried out only for a limited number of recent events, the results have provided useful hints for analysing the risk associated to this type of landslides in Campania. While it has originally been developed with regard to the volcaniclastic soil covers of Campania, where the role of discontinuities is generally deemed as particularly relevant to the spatial distribution of the source areas of debris slides, the method discussed in the present paper could profitably be used (with suitable adaptation and calibration) for assessing the rainfall-triggered shallow landsliding susceptibility also in different, residual and/or colluvial soil, contexts.

In this paper the results of the application of a method for the assessment of volcaniclastic soil sliding susceptibility to sample areas of Campania are presented. The method, called SL.I.DE. (from SLiding Initiation areas DEtection), is based on the concept that, for a spatially homogeneous soil cover and a spatially homogeneous triggering rainfall sequence, there exist different values of threshold slope gradient for limit equilibrium conditions, depending on the continuity and planform curvature of the soil cover. A large part of Campania, which forms an arc-shaped belt that, from N of the Mt. Somma-Vesuvius goes clockwise to S of it, within a radius of some tens of kilometres from the volcano, is extensively covered by volcaniclastic soils that derive from the alteration of airfall-sedimented ashes and pumices. The geomorphology of the steep slopes they cover is largely independent of the soils, as the latter represent a thin veneer upon carbonatic bedrock. In this part of Campania landslides within such soils are frequent, following intense and/or prolonged rainfall events. Such landslides can be classified as complex ones, occurring initially as debris slides but rapidly evolving through liquefaction into debris avalanches and/or debris flows. The consequences of debris avalanches and flows at the foot of slopes and at gully outlets have too often been catastrophic, and in recent decades the risk associated to such landslides has been growing, due primarily to increased and often uncontrolled urbanization. While the localization of such landslides depends on both the spatial distribution of some characters of the soil cover and on the spatial distribution of the triggering rainfall event, it appears reasonable to focus on the former, in order to attempt to assess the soil sliding susceptibility in the event of a triggering rainfall sequence, as it begins to appear evident that landslide-triggering rainfall can indeed occur over very limited areas. To this regard, extensive real-time monitoring of rainfall on volcaniclastic soil covered slopes has not yet been implemented in Campania, as there exist very few automatic rain gauges on the slopes, and weather radars do not exist yet. Therefore, an assessment of the soil sliding susceptibility in case of triggering rainfall proves useful, as it allows to consider also soil stabilization directly at sliding-susceptible areas within the framework of the evaluation of the options for reducing the risk related to such landslides in the studied area. In order to test the effectiveness of the SL.I.DE. method at assessing where soil slides can originate in case of triggering rainfall, it has been applied to some slope areas where such landslides have occurred either recently or repeatedly in the past, providing data regarding the position of source areas that can be considered sufficiently reliable. Comparison between actual landslides’ source areas and areas that were identified as susceptible provided good results. In addition, a comparison with the results obtained by means of other published methods on the same areas is also provided.

In a considerable part of Campania, landslides that originate in pyroclastic soil covers are rather common phenomena after intense and/or prolonged rainstorms. The fact that such landslides predominantly originate as debris slides draws attention towards the possibility of investigating the spatial component of the related hazard, based on the spatial distribution of past landslides. The latter is related to the spatial characters of the soils and their bedrock, as well as to the spatial distribution of critical rainfall sequences. The attempts that have been made in the last two decades to relate landslides that occurred over limited areas to rainfall data that were, on the other hand, significant in terms of averages over larger areas, achieved only partial success. This is due to the fact that the rainfall data were collected too coarsely for landslide analyses and, in addition, at elevations that were generally much lower than those of the initial debris slides. The spatial distribution of most of these landslides for a given sequence indeed demonstrates the fact that landslide-triggering rainfall sequences in Campania can be highly variable over space, even within short distances. It appears reasonable, however, to approach the volcanic debris slides spatial distribution problem independent of the spatial distribution of the triggering rainfall events. This allows to concentrate on the possible assessment of where landslides of this type can originate in case of critical rainfall. The application of the distributed modeling approach, either based on assumptions of steady-state or transient rainfall rates and flow, has shown however only partial effectiveness in identifying the loci of initial sliding for such landslides. This is due to the fact that (i) a significant percentage of such slides originate on steep slopes, where little or no relationship with drainage patterns can be recognized, and (ii) the majority of them occurs just above or below discontinuities of the soil cover, generally represented by rock cliffs or artificial cuts, where these methods are not applicable due to the assumption of infinite slope. For slides within soils on carbonate reliefs, several Authors report that the crowns of the studied landslides occurred within 10 m of a soil discontinuity (above or below it) for percentages averaging about 60% of the total studied landslides. The concentration of initial slides close to discontinuities in the soil cover is understandable because, for a spatially homogeneous precipitation pattern over a given soil cover of homogeneous properties, the slope gradient at which limit equilibrium conditions are reached can reasonably be considered higher where the cover is continuous than where the same cover shows unsupported and/or free drainage surfaces, as it does above or below discontinuities. A consequence of these findings is that it would be desirable to separate the crown and sliding zone slopes statistics for landslides that originate within continuous volcanic soil covers from those that originate within discontinuous ones. In this framework, a method is proposed for the assessment of the susceptibility to sliding of volcanic soils in Campania, based (i) on a good resolution assessment of slope gradients, (ii) on the detection of discontinuities in the volcanic soil cover, and (iii) on slope variation patterns. The aim of the research in which the method has been developed is to investigate the spatial component of the widely perceived “unpredictability” of this type of landslides, by means of searching the slope areas which can be more susceptible to sliding of the volcanic soil cover. Starting from these, guidelines for further investigation of landslide hazard and risk mitigation strategies can be developed, based not only on the presumable avalanche-flow paths and on vulnerability considerations downwards, but also on local, targeted stabilization of the volcanic soil cover itself.

La possibilità di determinare dove possono avere origine, nei suoli piroclastici di copertura di versanti acclivi, le frane di scivolamento-colata che così spesso hanno conseguenze catastrofiche in Campania rappresenta un tema con potenziali importanti risvolti applicativi. Ciò perché, in mancanza di un quadro di riferimento concretamente utilizzabile per tale determinazione, non è stato finora possibile perseguire strategie di riduzione del rischio conseguente a tali frane che comportino anche, attraverso opere di difesa attiva, una riduzione della probabilità d’innesco delle frane stesse. Nel presente lavoro si illustra un possibile metodo di individuazione delle aree di versante maggiormente suscettibili allo scivolamento dei suoli piroclastici. Il metodo si basa sulla separazione delle coperture interessate da discontinuità dalle coperture continue e sulla conseguente applicazione di diversi valori di pendenza “soglia” in caso di sequenze di pioggia critiche. Il metodo (denominato “SL.I.DE. (rev. 0)”, da Slide Initiation areas DEtection) trae spunto dall’osservazione di alcune caratteristiche delle frane del maggio 1998 sul Pizzo d’Alvano. Esso è stato quindi applicato alle coperture (pre maggio 1998) dello stesso Pizzo d’Alvano, per sperimentarne le possibilità. I risultati sono stati piuttosto soddisfacenti, tenendo conto che è stato per ora necessario adottare alcune ipotesi esemplificative, relativamente alle quali ulteriori conoscenze e dati potranno permettere l’implementazione nel metodo stesso anche di altri fattori spaziali.

L’evoluzione morfo-strutturale delle colline di Napoli si correla alle eruzioni flegree tardo-Pleistoceniche, all’attività della fault zone che borda a NE la piana del Sebeto ed a N il Golfo di Napoli, a rimodellamenti fluvio-denudazionali ed alla nascita di falesie e piane durante la trasgressione post glaciale. All’apice di quest’ultima una baia di sommersione occupa il settore Municipio; ad E una piattaforma di abrasione si arresta sotto la scarpata di faglia del Pendino e la costa si articola fino al profondo seno nella piana del F. Sebeto. Tale assetto favorisce gli insediamenti umani fin dalla preistoria. Tracce di frequentazione si datano al Bronzo Medio nel settore Duomo, mentre nelle insenature costiere esse risalgono almeno al v-iv sec. a.C. La baia di Municipio viene scelta come area portuale a partire dalla fine del iv sec. a.C. restando attiva fino al Tardo Antico, quando, nei diversi settori, si registrano condizioni di progressivo impaludamento. Una subsidenza tardo-olocenica stimata tra 4 e 7 m circa si manifesta con ritmi diversi nei vari settori indagati. Le contexte géomorphologique de Naples au Quaternaire est prioritairement contrôlé par l’activité volcanique des Champs Phlégréens et l’activité tectonique de la zone de failles qui limite le golfe de Naples de la plaine de Sebeto. À l’Holocène moyen, la transgression marine aboutit à l’immersion de l’actuelle place Municipio. Ces éléments géomorphologiques favorisent le développement des activités humaines durant la Préhistoire. Dans le secteur du Duomo, des traces de fréquentation humaine sont datées du Bronze moyen. La baie de place Municipio est utilisée dès les v-ive siècles avant Jésus-Christ. Cette baie est transformée en port dès la fin du ive siècle avant Jésus-Christ et demeure en activité jusqu’à l’Antiquité tardive, date à laquelle, elle est définitivement colmatée. Nos travaux ont mis en évidence une subsidence variable selon les secteurs entre 4 et 7 m depuis la fin de l’Holocène. The late Quaternary geomorphological setting of Naples is primarly controlled by both the volcanic activity of the Phlegrean Fields and the vertical displacement of the NE-SW trending fault zone bounding the Gulf of Naples and the Sebeto plain. At the beginning of the post-glacial transgression, fluvial erosion and marine cliff modelling also occurred on the southern flank of the hilly landscape of Naples. During the mid-Holocene, sea-level rise formed a bay in the Municipio area while to the north-east the paleoshoreline followed the NE-SW trending fault scarp overlooking the Pendino area. Since prehistorical times this geomorphological setting has influenced human settlement; in the coastal area the first archaeological findings date back to the Middle Bronze Age at Duomo and to the 5th-4th cent. B.C. in the southernmost coastal inlets. From the end of the 4th cent. B.C., Municipio bay accommodated a port which functioned until late antiquity, after which time infilling of the cove occurred. The archaeological and geological sea-level indicators allow different rates of late Holocene subsidence (from 4 to 7 m) to be estimated for various sectors of the investigated coastal area of Naples.

InfraRed Thermography has been tested herein for the study of the fracturing condition of intensely jointed rock masses, in order to find out what kind of information can be assessed. Although this technique is widely used in several scientific fields, its direct application for rock mechanics purposes is still under development. In this paper, thermal imaging campaigns, carried out in different climatic conditions, are described. A Cooling Rate Index, related to how fractured rock masses behave during the heat transfer towards the external environment, is proposed. Such an index has been related to the degree of fracturing of the rock masses, in order to find a relationship among thermal behavior and the main quantitative fracturing indexes. Results return interesting matches between some geostructural features and thermal outputs, demonstrating the reliability of the application of such methodology to bare rock masses. Moreover, new experimental considerations are proposed, laying the foundations for future studies aimed to further validate the InfraRed Thermography as an effective remote survey technique.

The present paper illustrates the results of an integrated study of a large landslide located on the southern slope of Mount la Civita (Molise, Southern Apennine), an E-W elongated, SSE dipping and 890-m-high monocline carbonate ridge. The upper part of the slope affected by the landslide is largely controlled by strata attitude while its basal part is marked by a strike-slip fault causing the tectonic juxtaposition of the carbonate successions against predominantly clayey flysch units. An integrated study, including geological, geomorphological and geotechnical investigations, was carried out to determine the features of the landslide and to plan further investigation and monitoring. In particular, from 2002 to 2004, Differential Global Positioning System monitoring and core drillings, coupled with inclinometer measurements, were carried out to determine the landslide's kinematics, extent, depth to the surface of rupture and rates of movement. Inclinometer data revealed the presence of the rupture surface at a depth of about 20 m. DGPS monitoring allowed rates of movement up to several tens of centimetres per year to be recorded. The nearby village of Civitanova del Sannio can still be considered at risk due to the landslide, as recent remedial works, consisting mainly of very shallow re-shaping of the slope by blasting and partial filling of trenches, did not succeed in stopping its movement. © 2012 Springer-Verlag.

A significant part of Campania is extensively covered by volcaniclastic soils, deriving from the alteration of airfall-sedimented formations of layered ashes and pumices that were ejected by Campi Flegrei and Mt. Somma–Vesuvius during explosive eruptions. Where such soils cover steep slopes cut in carbonate bedrock, landforms depend essentially on the morpho-evolution of such slopes prior to the deposition of the volcaniclastic soils, because these are generally present only as thin veneers, up to a few meters of total thickness. Historical records and local literature testify that, in this part of Campania, landslides that originate on carbonate slopes covered by such soils and terminate at their foot or at gully outlets are frequent, following critical rainfall events. Such landslides can be classified as complex, occurring initially as debris slides, but rapidly evolving into debris avalanches and/or debris flows. The localization of the initial sliding areas (i.e. ‘‘sources’’) on the slopes depends on both the spatial distribution of characters of the soil cover and the spatial distribution of the triggering rainfall events. It therefore appears reasonable to separate the two aspects of the problem and focus on the former one, in order to attempt an assessment of soil sliding susceptibility in the event of landslide-triggering rainfall. In this paper, some results of the application of a method aimed at such an assessment are presented. The method, called SLIDE (from SLiding Initiation areas DEtection), is based on the concept that, for a spatially homogeneous soil cover and a spatially homogeneous landslide-triggering rainfall sequence, different values of threshold slope gradient for limit equilibrium conditions exist, depending on morphological characters of the soil cover, such as its continuity and planform curvature. The method is based on the assessment of (1) soil cover presence, (2) discontinuities within soil cover, (3) slope gradients and curvature, by means of good resolution DEMs. It has been applied to sample carbonate slopes of Campania, where landslides originated either repeatedly or recently. Results are encouraging, and a soil sliding susceptibility map of a large area, based on a simplified version of method, is also presented.

The application of Infrared Thermography is here proposed as a useful tool for the remote survey of intensely jointed rock slopes. Although such a technique is widely used in several scientific fields, its direct application for the evaluation of the degree of fracturing in bare rock masses is still a pioneering methodology. To test and validate its application, two representative rock masses of different lithologies have been chosen in the southern sector of Peloritani Mountains (north-eastern Sicily). Thermal images were taken during three moments of the same day, to study the thermal behavior of the rock under heating and cooling conditions. Results show interesting matches between some geostructural features and thermal outputs, demonstrating the reliability of such a methodology, which can also allow the extension of the survey to portions of the slope that are not directly reachable.

A complex landslide, which mobilized a calcareous rock mass of about 60,000 m3, occurred on January 3, 2002, along the southwestern slope of Mt. Catiello, above Positano (province of Salerno, Italy). According to established classification schemes, such a landslide can be classified as a rock avalanche or as a complex, dry, extremely rapid rock fall—dry, extremely rapid debris flow. Landslides of this type and dimensions are quite rare in the southern Apennines, and even rarer in the Sorrento-Amalfi Peninsula. Therefore this one represents a singular case for assessing both the mechanisms leading to such a type of sudden, often hazardous mass movements, and the residual hazard still existing on Mt. Catiello. Due to the inaccessibility of the near-vertical rock slopes, the characterization of the instability mechanisms of the landslide was based on analyses of terrestrial stereoscopic photographs, taken from lateral and frontal positions with respect to the 2002 depletion zone, and on measurements/validations of structural settings carried out in accessible sectors of the mountain. Currently, the southwestern slope of Mt. Catiello, which corresponds to the depletion zone of the 2002 landslide, cannot be considered more unstable than the adjacent northern slope, where a smaller rock mass tower, with a volume of 20,000 m3 and clear signs of a propagating deformation-fracturing process at the base, was identified. Considering this remaining unstable rock tower as a part of the mass movement, the distribution of activity of the landslide can be considered as widening, and its state of activity as suspended.