Search

Interferometric methods are drivers of the recent exponential growth in the use of synthetic aperture radar (SAR) for monitoring both natural and anthropogenic hazards. Since the first use of interferometric SAR (InSAR) in the late 1990s to detect deformations associated with earthquakes and volcanoes, important developments have improved sensor performance and data-processing capabilities for the extraction of information of interest in geophysical applications. Here, we describe the improvements that have enabled the 3D reconstruction and monitoring of buildings, with reference to their protection against and prevention of risks. We focus on buildings affected by systematic displacements related to natural hazards-specifically, landslides. We address the straightforward use of InSAR methods in the detection and characterization of the hazard as well as in higher-level exploitation for geotechnical and structural studies and, more generally, vulnerability analysis.

The reconnaissance, mapping and analysis of kinematic features of slow-moving landslides evolving along medium-deep sliding surfaces in urban areas can be a difficult task due to the presence and interactions of/with anthropic structures/infrastructures and human activities that can conceal morphological signs of landslide activity. The paper presents an integrated approach to investigate the boundaries, type of movement, kinematics and interactions (in terms of damage severity distribution) with the built environment of a roto-translational slow-moving landslide affecting the historic centre of Lungro town (Calabria region, southern Italy). For this purpose, ancillary multi-source data (e.g. geological-geomorphological features and geotechnical properties of geomaterials), both conventional inclinometer monitoring and innovative non-invasive remote sensing (i.e. A-DInSAR) displacement data were jointly analyzed and interpreted to derive the A-DInSAR-geotechnical velocity (DGV) map of the landslide. This result was then cross-compared with detailed information available on the visible effects (i.e. crack pattern and width) on the exposed buildings along with possible conditioning factors to displacement evolution (i.e. remedial works, sub-services, etc.). The full integration of multi-source data available at the slope scale, by maximizing each contribution, provided a comprehensive outline of kinematic-geometric landslide features that were used to investigate the damage distribution and to detect, if any, anomalous locations of damage severity and relative possible causes. This knowledge can be used to manage landslide risk in the short term and, in particular, is propaedeutic to set up an advanced coupled geotechnical-structural model to simulate both the landslide displacements and the behavior of interacting buildings and, therefore, to implement appropriate risk mitigation strategies over medium/long period.

The analysis of consequence induced by landslides to the built environment is a key step in the landslide risk management process. For this purpose, a thorough knowledge of both the landslide mechanisms and the behaviour/characteristics of the exposed elements turn out to be crucial. Currently, scientists and technicians have access to unprecedented big data sources that provide a variety of useful information on landslide-affected areas. With reference to slow-moving landslides, this paper presents some case studies of an ongoing research aimed at defining and testing original procedures pursuing the exploitation of innovative monitoring/surveying techniques for the analysis and forecasting of vulnerability of buildings and roads.

Quantitative analysis of consequences (in terms of expected monetary losses) induced by slow-moving landslide mechanisms to buildings or infrastructure networks is a key step in the landslide risk management framework. It can influence risk mitigation policies as well as help authorities in charge of land management in addressing/prioritizing interventions or restoration works. This kind of analysis generally requires multidisciplinary approaches, which cannot disregard a thorough knowledge of landslide mechanisms, and rich datasets that are seldom available as testified by the limited number of examples in the scientific literature. With reference to the well-documented case study of Lungro town (Calabria region, southern Italy)—severely affected by slow-moving landslides of different types—the present paper proposes and implements a multi-step procedure for monetary loss forecasting associated with different landslide kinematic/damage scenarios. Procedures to typify landslide mechanisms and physical vulnerability analysis, previously tested in the same area, are here appropriately merged to derive both kinematic and damage scenarios to the exposed buildings. Then, the outcomes are combined with economic data in order to forecast monetary loss at municipal scale. The proposed method and the obtained results, once further validated, could stand as reference case for other urban areas in similar geo-environmental contexts in order to derive useful information on expected direct consequences unless slow-moving landslide risk mitigation measures are taken.

This paper presents the results of a numerical analysis aimed at investigating the response – in terms of damage occurrence and development – of a masonry building undergoing settlements induced by a slow-moving landslide. The analysis is performed by applying the Equivalent Frame Method to a model representative of a low-rise building with shallow foundations located in the historic centre of Lungro town (Calabria region, southern Italy). As a main novelty, data collected by way of both conventional (i.e. inclinometers) and innovative (i.e. DInSAR) monitoring techniques are used to derive the three-dimensional settlement trough to be imposed to the building model’s foundation in the numerical analyses. The obtained outcomes are compared with information gathered from multi-temporal damage surveys to the modeled building. Based on previous studies aimed at typifying the slow-moving landslides, the results obtained could concur to the generation of certain building-foundation-landslide typified models helpful for damage forecasting at the municipal scale.

Le frane e la loro conoscenza, essenziale per progettare gli interventi che concorrono alla gestione del rischio, presentano notevoli complessità e richiedono un impegno rilevante di tempo e di risorse. L'analisi sistematica dei risultati di studi su frane rappresentative in contesti geo-ambientali e sociali omogenei consente di individuare "famiglie" di frane tipizzate costituite da due o più frane che presentano un adeguato numero di elementi caratteristici simili (geomateriali, profondità massima, velocità caratteristiche, ecc.). Il metodo proposto nella nota consente una comprensione più rapida dei meccanismi di frana riconducibili ad una famiglia di frane tipizzate e, ancora, di trasferire e utilizzare le conoscenze dal singolo versante, all'area vasta ed all'analisi regionale in maniera circolare ed efficace. La diffusione delle rocce metamorfiche in Calabria, gneissiche in particolare, e il profondo grado di alterazione che le caratterizza, le espone ad un'elevata suscettibilità alle frane. In tale scenario, il metodo proposto ed i risultati che fornisce costituiscono utili strumenti per la definizione di efficaci strategie di intervento per l'adattamento, la mitigazione e la riduzione del rischio da frana. Utilizzando risultati relativi ad aree e siti oggetto di studi interdisciplinari, sono illustrati nella nota gli elementi di frana tipizzati con i livelli di analisi considerati (regionale, su area vasta e di dettaglio). La discussione dei risultati delinea la praticabilità del percorso proposto e conferma l'utilità a sviluppare l'approccio, con i dovuti approfondimenti e le necessarie precisazioni, per altri contesti geoambientali. Si rileva, in conclusione, come la disponibilità di frane tipizzate consente su area vasta di pianificare le priorità degli interventi e di programmare al meglio l'utilizzo delle risorse disponibili, mentre per il singolo versante permette di massimizzare le conoscenze a parità di risorse disponibili e, quindi, di garantire una maggiore sostenibilità socio-economica degli interventi nel medio-lungo termine. Gli elementi tipizzati con livello di analisi regionale indirizzano, infine, la scelta di aree di studio rappresentative di particolari possibili condizioni di rischio.

Community resilience is the ability of people exposed to disasters, crises and underlying vulnerabilities, to anticipate, to prepare for, to reduce the impact of, to cope with and to recover from the effects of shocks and stresses without compromising their long-term prospects. In February 2010, the town of Maierato (Calabria, southern Italy) was hit by a large landslide, which radically changed the morphology of the territory and produced an important social and economic impact. The aim of this paper is to deal with the concepts of social vulnerability and community resilience, within the framework of the landslide risk governance and the perception of the risk. Survey was conducted by means of a structured questionnaire interviewing 200 adults. Results, analyzed by means of qualitative methods with the support of descriptive statistics, highlighted several important remarks. Globally, this case study indicates that urgent actions should be taken to reduce disaster-risk such as: improving citizens' understanding of disaster management, reinforcing risk governance to improve disaster management, investing in risk mitigation and programs fostering adaptation and resilience, improving emergency planning strategies.

Several urban areas in Euro-Mediterranean countries are affected by slow-moving landslides that, even if rarely associated with the loss of human life, can cause damage to structures and infrastructure. In such contexts, the progressive decay of the built environment can bring along a generalized increase of the physical vulnerability and, as a result, slow-moving landslide risk increases over the time. Under these conditions, as long as suitable risk mitigation measures are lacking, the level of risk (also related to earthquakes) could turn out to be no longer acceptable within an a priori unknown time interval. This problem has a relevant social-economic impact, thus requiring the adoption of risk mitigation strategies that need to be effective and, at the same time, sustainable for the involved stakeholders. In this regard, this paper proposes a multi-scale methodological approach—based on the joint use of satellite-derived displacement monitoring data and the results of building damage surveys—whose applicability is tested with reference to urban areas affected by slow-moving landslides in Calabria region (southern Italy).

Slow-moving landslides are widespread natural hazards that can affect both social and economic activities causing damage to structures and infrastructure networks. This paper aims at providing an innovative simplified procedure to analyse road damage induced by slow-moving landslides based on the joint use of landslide inventory maps, a road damage database (collecting both the results of in-situ surveys and Google Street View images) and ground displacement measurements derived from the interferometric processing of satellite SAR images (DInSAR data). The procedure was applied to the case study of the Calabria region (southern Italy) following a two-scale approach. First, a regional-scale analysis was carried out to gather information on the level of road exposure (namely, Index of Exposed Roads) to slow-moving landslides in order to identify the most representative case studies. Then at local scale, relationships between road damage severity level and a selected parameter (i.e. differential settlement computed in two different ways) of slow-moving landslide intensity were derived for two road stretches that differ in geo-lithological and topographic conditions. The results underline the importance of the availability of both reliable landslide inventories and rich road damage databases as well as the potential of high-resolution DInSAR data for obtaining quantitative information on movement rates of roads useful to carry out in-depth studies pursing vulnerability analyses of the infrastructure.

The geometric and kinematic characterization of landslides affecting urban areas is a challenging goal that is routinely pursued via geological/geomorphological method and monitoring of ground displacements achieved by geotechnical and, more recently, advanced differential interferometric synthetic aperture radar (A-DInSAR) data. Although the integration of all the abovementioned methods should be planned a priori to be more effective, datasets resulting from the independent use of these different methods are commonly available, thus making crucial the need for their standardized a posteriori integration. In this regard, the present paper aims to provide a contribution by introducing a procedure that, taking into account the specific limits of geological/geomorphological analyses and deep/surface ground displacement monitoring via geotechnical and A-DInSAR data, allows the a posteriori integration of the results by exploiting their complementarity for landslide characterization. The approach was tested in the urban area of Lungro village (Calabria region, southern Italy), which is characterized by complex geological/ geomorphological settings, widespread landslides and peculiar urban fabric. In spite of the different level of information preliminarily available for each landslide as result of the independent use of the three methods, the implementation of the proposed procedure allowed a better understanding and typifying of the geometry and kinematics of 50 landslides. This provided part of the essential background for geotechnical landslide models to be used for slope stability analysis within landslide risk mitigation strategies.

Mass movements of different thicknesses and types affect the slope where the Greci and Piscopie villages lie (Lago, Calabria, Italy). The study concerns a moderately urbanized area where the lithological, structural, and hydrogeological conditions have produced a large and complex unstable area. In the study area, a multi-temporal field survey has allowed for detailed landslide inventory mapping and definition of the geometric and kinematic characteristics of mass movements with long-term monitoring. In particular, an integrated monitoring network was progressively put in place, since 1996 to measure superficial and deep displacements (GPS stations and inclinometers). The network dataset shows that the mass movements in the study area are characterized by an extremely slow or very slow rate of displacement. The elements acquired by a long-term monitoring of the deep displacements point out that the landslide bodies are prone to develop new failure surfaces progressively shallower, with a consequent increase of the hazard. Moreover, medium-deep and deep-seated landslides may rapidly accelerate in relation to rainfall conditions and significantly affect structures and infrastructures. The integration of the geological and geomorphological knowledges with the monitoring data allows for distinguishing six different homogeneous sectors on the slope, as well as the relative geometric and kinematic characteristics, and the type of mass movements. In the study area, which is representative of several aspects of other areas, the method proposed and the knowledge acquired by long-term monitoring could be useful to define mass movement mechanisms, geotechnical models, and risk mitigation strategies.

Slope failures are the result of various predisposing factors (geo-structural and morphological conditions, topography, geotechnical characteristics, etc.). In an ordinary phase, a typical slope stability analysis includes the identification of factors that can trigger a slope failure, its mechanisms, the modelling of stability conditions and their assessment during critical situations. To define the predisposing and triggering factors, integrated monitoring represents an essential and powerful tool. In this paper, referring to the case study of a medium-deep landslide that occurred in Calabria (Southern Italy) during the winter of 2009–2010, a method and means of defining an emergency geotechnical model (smart geotechnical model) using a geological model are proposed. The definition of both models considers the resources that may be obtained in an emergency and the short time available to achieve the objectives (protection of public and private safety, restoration of normal conditions, etc.). The proposed method allows the orderly and systematic acquisition, under emergency conditions, of data that are useful for the management of a particular situation and for defining an initial cognitive state of the problem. These elements can be particularly effective in both emergency (to manage risk using progressively quantitative knowledge) and ordinary conditions to plan, design, realize and manage definitive measures for risk adaptation, mitigation and reduction. Moreover, the same knowledge can provide useful references to typify landslides that occur in similar geo-environmental contexts.

Shallow landslides (i.e., slide, flow, and complex) are widespread around the world, affecting the soil mantle and upper regolith as a result of the weathering of granitic bedrock, and periodically cause enormous social and economic damages. Shallow landslide hazards are predominantly due to the scarcity of warning signs during the pre-failure stage, high velocities reached in the post-failure phase, and an increase in mobilized volumes caused by the entrapment of material in the downhill path of the phenomena. Owing to the abovementioned aspects, susceptibility assessment of shallow landslides in weathered granitic rocks is a relevant issue for land use planning and design purposes. This study proposes a three-step methodology for the susceptibility assessment of these phenomena. The methodology has been tested and validated at the 1:10,000 scale over a 30.4-km2 area in southern Italy, where weathered granitic rocks are periodically affected by shallow landslides. This methodology is divided into three successive steps: step 1 consists of database creation, with an emphasis on the weathering grade map (including five weathering classes, from class II to class VI, each one characterized by comparable mechanical behavior), and steps 2 and 3 focus respectively on susceptibility map calibration and validation through statistical analyses. The area under the ROC curve (AUC) shows values ranging from 0.95 in step 2 (calibration) to 0.88 in step 3 (validation) and is a testament to the good overall predictive accuracy of the methodology. The obtained results demonstrate both the effectiveness and the consistency of the proposed methodology in performing susceptibility mapping of shallow landslides in weathered granitic rocks, as well as the important role played by the weathering grade map.

This paper presents a mass movement inventory map at 1:5000 scale of the Verbicaro area (about 13 km2) located in the Calabria region (southern Italy). The Main Map results from the visual interpretation of aerial photographs, multi-temporal geomorphological field surveys, and field investigations of damage suffered by buildings. Some 53% of the study area is affected by a total of 252 landslides, comprising different types, state of activity, and size. The mapped landslides, mainly complex type, involve low-grade metamorphic rocks; among these, 15% are active and slow-move on pre-existing sliding surfaces. Moreover, out of 492 surveyed buildings, 347 are located on landslide-affected areas and experienced damages covering a broad range of severity levels. The Main Map can represent a useful tool for authorities in charge of land-use planning and urban management and can be used to pursue landslide risk analyses.

This paper illustrates the methodology and techniques for the compilation of a thematic (engineering) geological map based on detailed mapping of the weathering grade of crystalline rocks occurring in a portion of the Sila Massif close to the San Giovanni in Fiore Village (Calabria, Italy). The map (1:5000 scale), covering an area of about 20 km2, was compiled combining new geological and structural data with the results of a weathering grade field survey. The methodology, used to distinguish and map the weathering grade classes, was performed using qualitative criteria, semi-quantitative tests, and petrographic analysis of weathered rock samples. The Main Map, presented in this paper, aims to provide a useful tool for land-use planning, for geological hazard assessment and engineering perspectives.

On 15 February 2010, as a result of intense and long-lasting rainfalls, a large landslide affected a wide area near the town of Maierato (Calabria, Italy). The studies conducted – including (i) aerial photo interpretation, (ii) geological and geomorphological field investigations, (iii) interpretations of lithology and stratigraphy from borehole data, and (iv) observation of videos filmed during the main diastrophic phases of the landslide and of antecedent Google Street View® images – allowed researchers to reconstruct the geological and tectonic setting of the slope and the internal structure of the landslide with the estimation of the depth of the sliding surface, the triggering mechanisms and its evolution. The analysis of the prelandslide event setting demonstrates that this mass movement is the reactivation of a preexisting landslide of alleged seismic origin, remaining at an incipient stage. The Maierato landslide occurred on a gentle slope made of late Miocene to Plio-Pleistocene clastic and evaporitic sedimentary rocks. The main basal failure surface that developed on the hemipelagic marls has a maximum depth of 50 m. The volume of the landslide is ~ 5 million cubic meters. The type of landslide movement is a complex one, consisting of a very rapid slide of rock and earth and of flow of debris and earth. The landslide clearly shows three major types of failure mechanisms: the first type is described as a rapidly moving rotational slide where back-tilted blocks of sediment are preserved; the second type includes a very rapidly moving translational slide of large rock blocks; the third type includes sudden, extremely rapid flow-slides where the slide material is disaggregated while flowing downward along a gentle slope. The slide is a compound one, with a retrogressive evolution and transformation into earth and debris flow during the failure. After the triggering of the landslide, and as a result of the relevant displacement, an important portion of the lower evaporitic unit ( Calcare di Base Formation), close to the failure surface, collapsed, thereby undergoing a quick change of its mechanical behavior that became similar to that of a viscous fluid. During the landslide evolution, large rocky blocks consisting of Miocene evaporitic limestones, Pliocene silty clays, and sands were rafted, without severe disturbance, on the destructurated and fluidized limestone. The intense destructuration and the presence of water transformed the limestone (in the lower parts of the unit) into a viscous material that was squeezed out of the landslide mass through the jags between the several rafted rocky blocks and along the natural levees of flow tongue. This event is a rather frequent combination of mass movements made complicated and spectacular by the fluidization of the weak limestone that imparted great dynamics to the movements. Such fluidization is an infrequent phenomenon especially in this geological context.

The paper deals with the development of a multidisciplinary research on weathering profiles of granitoid and gneissic rocks related to tectonic and landscape evolution of the western Sila Grande Massif (Calabria, southern Italy). Field scale observations and petrographical and mineralogical features are used to characterize in detail the weathering processes. The weathering profiles of the granitoid cut slopes are generally simple showing a progressive weathering increase toward the top of the slopes, whereas the weathering profiles of the gneissic cut slopes are generally complex with irregularities in the spatial distribution of weathered horizons. The microfabric and petrographic analyses show that gneissic samples (classes V–VI of weathering grade) are characterized by higher percentage of altered minerals and microfracture and void rather than granitoid samples (classes V–VI of weathering grade). The main mineralogical changes concern the partial transformation of biotite and the partial destruction of feldspars (mainly plagioclases), associated with the neoformation of secondary minerals (clay minerals and Fe-oxides) and with a substitution of the original rock fabric. Neoformed clay minerals and ferruginous products replaced feldspars and biotite during the most advanced weathering stage. Referred as physical changes coupled with chemical variations, the final results of weathering process are a soil-like material characterized by sand–gravel grain-size fraction for the granitoid rocks and by both silt–clay and sand–silt grain-size fraction for the gneissic rocks. This generally produces a greater value of the SGI (Sand Generation Index) for granitoids and explains the great productivity in sandy deposits of this lithology.

Calabria is one of the Italian regions mostly affected by mass movements. The case study of a densely populated neighborhood (Iano) located in the central-western sector of Calabria is presented. The several landslides triggered in February 2010 caused heavy damages to the built area, infrastructures and productions of this neighborhood, and increased the risk for the inhabitants. The results obtained through field surveys, photo interpretation, analyses of rainfall data and of the urban fabric evolution, historical survey on the reports of the damages caused by landslides, have enabled to formulate hypotheses on the potential causes that triggered landslide events and produced severe consequences on the area. These results have revealed that almost all landslides of February 2010 are partial reactivations of pre-existing landslide deposits. Moreover, the analyses have indicated a critical role of cumulative rainfalls over an interval of 15 days. However, the severe damage framework is explained through an unplanned urbanization which took place across the years on an area characterized by a high level of instability per se. Some buildings have been erected in proximity of or within pre-existing landslide scarps; in other cases, buildings have been constructed even inside the landslide bodies.

La nota riassume quanto presentato nei "Seminari Operativi" di "Calabria Sicura" del 24 ottobre 2016. In particolare, assumendo come riferimento le proposte portate dal CNR-IRPI al tavolo tecnico sul "Rischio idrogeologico" e considerando le connessioni dei tre tavoli tecnici, sono evidenziate le specificità e le sinergie delle soluzioni proposte e segnalati alcuni temi di ricerca utili per migliorarle e per mantenerle efficaci nel tempo.

Slow-moving landslides yearly induce huge economic losses worldwide in terms of damage to facilities and interruption of human activities. Within the landslide risk management framework, the consequence analysis is a key step entailing procedures mainly based on identifying and quantifying the exposed elements, defining an intensity criterion and assessing the expected losses. This paper presents a two-scale (medium and large) procedure for vulnerability assessment of buildings located in areas affected by slow-moving landslides. Their intensity derives from Differential Interferometric Synthetic Aperture Radar (DInSAR) satellite data analysis, which in the last decade proved to be capable of providing cost-effective long-term displacement archives. The analyses carried out on two study areas of southern Italy (one per each of the addressed scales) lead to the generation, as an absolute novelty, of both empirical fragility and vulnerability curves for buildings in slow-moving landslide-affected areas. These curves, once further validated, can be valuably used as tools for consequence forecasting purposes and, more in general, for planning the most suitable slow-moving landslide risk mitigation strategies.

Deep-seated rock slides (DSRSs), recognised as one of the most important mass wasting processes worldwide, involve large areas and cause several consequences in terms of environmental and economic damage; they result from a complex of controlling features and processes. DSRSs are common in Calabria (southern Italy) where the complex geo-structural setting plays a key role in controlling the geometry of the failure surface and its development. This paper describes an integrated multi-disciplinary approach to investigate a DSRS in Palaeozoic high-grade metamorphic rocks of the Sila Massif; it focuses on the definition of the internal structure and the predisposing factors of the Serra di Buda landslide near the town of Acri, which is a paradigm for numerous landslides in this area. An integrated interdisciplinary study based on geological, structural, and geomorphological investigations--including field observations of weathering grade of rocks, minero-petrographic characterisations, geotechnical investigations and, in particular, fifteen years of displacement monitoring--is presented. Stereoscopic analysis of aerial photographs and field observations indicate that the Serra di Buda landslide consists of two distinct compounded bodies: (i) an older and dormant body (~ 7 ha) and (ii) a more recent and active body (~ 13 ha) that overlies the previous one. The active landslide shows movement linked to a deep-seated translational rock slide (block slide); the velocity scale ranges from slow (1.6 m/year during paroxysmal stages) to extremely slow (< 16 mm/year during stable creep stages). The geological structures and rock weathering have played a key role in the landslide's initiation and further development. Steep slope angles, rugged topography, river deepening and erosion at the toe of the slope are also responsible for the formation of this landslide. In particular, the landslide shows a strongly tectonic constraint: the flanks are bounded by high-angle faults, and the main basal failure surface developed inside an E-W southward-dipping thrust fault zone. The entire active rock mass (total volume of approximately 6 Mm3) slid at one time on a failure surface that dipped < 27°, and the maximum depth, as determined by inclinometer measurements, was approximately 58 m. Petrographic and mineralogical analyses suggest that the rocks in the thrust zones, where the failure surfaces develop, are highly affected by weathering processes that significantly reduce the rock strength and facilitate the extensive failure of the Serra di Buda landslide. Finally, the landslide's internal structure, according to geotechnical investigations and displacement monitoring, is proposed. The proposed approach and the obtained results can be generalised to typify other deep landslides in similar geological settings.

La nota propone un contributo per la definizione di una filiera per avviare, mantenere e migliorare un percorso metodologico cui concorrono competenze e strumenti, di varie discipline, per sviluppare, utilizzare e approfondire conoscenze, metodi, procedure e tecnologie per l'adattamento, la mitigazione e la riduzione del rischio prodotto da eventi di dissesto idrogeologico.

In this paper, a simplified methodological approach is used to assess damage indices related to landslide phenomena that occurred in Calabria (Italy) between November 2008 and January 2009. This approach, which was designed for and applied to single landslides, uses the Support Analysis Framework (SAF), a procedure containing the elements that can be damaged by a landslide grouped in categories. In this paper, we test wide-ranging use of the SAF on a number of landslides, assessing landslide damage on a municipal scale to get a final estimate of the amount of damage caused by all of the landslides that occurred in a selected municipality. Data regarding the damage caused by landslides were gathered from the press. Daily newspapers were systematically collected and elaborated to assess direct, indirect and intangible damage caused during the abovementioned period by a rainfall-triggered landsliding event. In the paper, regional- and provincial-scale results are described, and the methodological approach is briefly described. The application of the proposed methodological approach to the 2009 landsliding event shows that the results can be used to summarise landslide damage from a complex event in order to better plan an intervention strategy at a regional, provincial or municipal scale. The availability of newspaper data during the event and the speed of the proposed approach allow for rapid location of the damaged sectors during the event, which will continuously upgrade the regional damage framework. This can all be done almost in "real time". For regional agencies, this framework can be a starting point to both manage the emergency and to acquire and interpret data giving a more detailed damage distribution so that a response can be organised. Moreover, based on the damage assessment, a characterisation of the landsliding event can also be carried out and used to describe the damage scenario occurring after each type of event.

The Support Analysis Framework (SAF) is a tool that converts descriptions of landslide effects into numerical indices expressing direct, indirect and intangible damage. Sections assessing direct damage are made up of ‘elements’ characterised by relative values and the ‘levels of loss’ that they can suffer. By typing an x value into the cell representing an element and a level of loss, formulas multiply the value of the element by the level of loss, obtaining a value used in the damage indices assessing. Indirect damage deals with: (a) emergency response and (b) efforts to restore pre-landslide conditions. The level of loss depends on the number of people affected (a) or the cost of actions (b). For intangible damage, the level of loss depends on the number of people affected. We assess the damage indices for a landslide occurred in Calabria (Italy) in 2005, using both the SAF and the SAFL, a customised version that takes into account the local socio-economic framework by including only elements present in the analysed municipality. We assess the damage indices for three scenarios with different initial conditions and compare them to the 2005 event; the results would have been useful to mitigate damage. The SAF can be used by nonspecialists, and it allows the ranking of damage caused by different landslides, thus supporting local authorities in prioritising countermeasures and civil protection offices to speed up responses to refund requests. The sorting of dormant phenomena according to their possible damage helps with defensive measures, emergency plans and insurance purposes.

The work aims at identifying susceptible areas and pluviometric triggering scenarios at a regional scale in Calabria (Italy), with reference to shallow landsliding events. The proposed methodology follows a statistical approach and uses a database linked to a GIS that has been created to support the various steps of spatial data management and manipulation. The shallow landslide predisposing factors taken into account are derived from (i) the 40-m digital terrain model of the region, an ∼ 15,075 km2 extension; (ii) outcropping lithology; (iii) soils; and (iv) land use. More precisely, a map of the slopes has been drawn from the digital terrain model. Two kinds of covers [prevalently coarse-grained (CG cover) or fine-grained (FG cover)] were identified, referring to the geotechnical characteristics of geomaterial covers and to the lithology map; soilscapes were drawn from soil maps; and finally, the land use map was employed without any prior processing. Subsequently, the inventory maps of some shallow landsliding events, totaling more than 30,000 instabilities of the past and detected by field surveys and photo aerial restitution, were employed to calibrate the relative importance of these predisposing factors. The use of single factors (first level analysis) therefore provides three different susceptibility maps. Second level analysis, however, enables better location of areas susceptible to shallow landsliding events by crossing the single susceptibility maps. On the basis of the susceptibility map obtained by the second level analysis, five different classes of susceptibility to shallow landsliding events have been outlined over the regional territory: 8.9% of the regional territory shows very high susceptibility, 14.3% high susceptibility, 15% moderate susceptibility, 3.6% low susceptibility, and finally, about 58% very low susceptibility. Finally, the maps of two significant shallow landsliding events of the past and their related rainfalls have been utilized to identify the relevant pluviometric triggering scenarios. By using 205 daily rainfall series, different triggering pluviometric scenarios have been identified with reference to CG and FG covers: a value of 365 mm of the total rainfall of the event and/or 170 mm/d of the rainfall maximum intensity and a value of 325 mm of the total rainfall of the event and/or 158 mm/d of the rainfall maximum intensity are able to trigger shallow landsliding events for CG and FG covers, respectively. The results obtained from this study can help administrative authorities to plan future development activities and mitigation measures in shallow landslide-prone areas. In addition, the proposed methodology can be useful in managing emergency situations at a regional scale for shallow landsliding events triggered by intense rainfalls; through this approach, the susceptibility and the pluviometric triggering scenario maps will be improved by means of finer calibration of the involved factors.

Geological and geomorphological criteria complemented with geotechnical monitoring of ground displacements are routinely applied for geometric and kinematic characterization of landslides. However, these activities may be challenging in densely built-up historic centres. In order to tackle all constraints posed by the presence of complex urban fabric, this paper proposes a procedure for integrating the results of geological/geomorphological analyses with deep and surface ground displacement data acquired via geotechnical monitoring and spaceborne Differential Interferometric Synthetic Aperture Radar (DInSAR) data. The selected test site is a village in southern Italian Apennines characterized by complex geological/geomorphological settings, widespread distribution of landslides and a peculiar urban fabric. The results of the integration procedure show that it is possible to overcome specific limits and provide a better understanding and definition of the geometry and kinematics of slow-moving landslides to be used for slope stability analyses and landslide risk management in historic centres.

The paper describes a methodology to detect landslide triggering scenarios in geological homogeneous areas and for some specific landslide categories. In these scenarios, the rainfall–landslide relationship as well as the pluviometric load conditions influencing slope instability have to be investigated. The methodology is applied to an area located in northern Calabria (Italy) and affected by widespread and different slope instability phenomena. Outcropped, fractured, and deeply weathered crystalline rock masses, determining geologic homogeneous conditions, are present. In the same area, suitable and homogeneous climatic features have also been found. According to the methodology adopted, the hydrologic analysis of rainfall time-series is initially carried out notwithstanding historical data concerning landslide mobilization, but using simple models to determine critical pluviometric scenarios for the three landslide categories: shallow, medium-deep, and deep. Landslide-triggering scenarios individualized according to this procedure are less significant as compared to the landslide mobilization detected in the study area by means of historical research and ascribed to the three landslide categories according to geomorphologic analysis. Subsequently, the possible landslide triggering scenarios are outlined by carefully investigating the hydrologic analysis limited to the periods identified according to the historical data. In the study area and approximately for all the areas characterized by the outcrop of fractured and deeply weathered crystalline rocks, significant triggering scenarios can be outlined. In particular, shallow landslide triggers could be activated by rainfall events with intensities exceeding 90 mm/day and/or with amounts exceeding 160 mm. As for medium-deep and deep landslides, triggering mechanisms are more complicated; and effective rainfall contribution must be taken into account compared to groundwater storage. Moreover, a more complex link between deep landslides and precipitation is confirmed. The results obtained to date highlight the potential of this methodology, which enables us to define and progressively improve the knowledge framework by means of a work sequence integrating different disciplinary tools and results.

In the last decades, building damage caused by landslides in urban areas has increased due to the rapid growth of urbanization even on landslide-prone slopes. This work presents the analysis results of landslide damage evolution by means of a macrodamage index in relation to the characteristics of landslides. The study area is located in southern Italy, and is affected by slow-moving landslides, which, over time, have caused relevant effects on the buildings. A series of geological and geomorphological studies and field surveys, supported by monitoring via conventional geotechnical techniques, allowed us to classify four categories of landslides based on the following criteria: landslide movement, type of material and estimated depth. Detailed field surveys aimed at evaluating distribution and evolution of the damage to buildings located within and near the unstable area were carried out in 2005 and 2011. The evaluation of the macrodamage index in two different years enabled us to directly correlate the features of the landslide categories and their effects on the urban fabric.

A deep-seated gravitational slope deformation (DSGSD) and a number of landslides of different thickness and types affect the Greci slope (Lago, Calabria, Italy). The geological settlement of the area is characterized by the presence of tectono-metamorphic thrust sheet belonging to the Calabrian belt. The study concerns a moderately urbanized area, crossed by an important road, where the lithological-structural and hydrogeological conditions predispose to slope instabilities. This paper deals with the kinematic characteristics relative to the instability mechanisms in the Greci slope, defined with a long term monitoring. Specialized monitoring networks have been progressively realized since 1996 to measure the surficial and deep displacements (GPS benchmarks, GPS permanent stations and inclinometer verticals). After a period of continuous and intense rainfall (2008–2010), a detailed landslides inventory map has been prepared to update the landslides boundaries. The new elements and data acquired confirm that the mass movements mechanisms in the Greci slope are characterized by extremely slow or very slow rate of displacements (Cruden and Varnes classification). Moreover, new knowledge demonstrate the landslides may significantly accelerate and affect structures and infrastructures.

This paper describes the activities conducted for the development of a thematic map of shallow landslides (and other landforms) resulting from by consecutive rainfall events during the fall-winter seasons of 2008/2009 and 2009/2010 in the Catanzaro Strait (Central Calabria, South Italy). The methodology is based on the interpretation of Google Earth high-resolution satellite images (post-event images are dated 19th March 2010), followed by processing and management of the collected data through a geographic information system. The inventory covers a wide area (692 km2) and includes 3483 shallow landslides and many other geomorphological features (zones of incipient shallow landslides and areas affected by soil erosion) related to the 2008–2010 rainfall events. The map produced may provide useful data to define shallow landslide events, develop landscape evolution models and characterise active geomorphic processes. Furthermore, the map may also be used as a basic tool to produce landslide or erosion susceptibility maps, which can be used for land-use planning strategies and landslide hazard analyses.

Crystalline rocks are often subjected to several types of mass movements, depending on their weathering grade. These rocks are present in the European area along the Italian and French Alps, in the North-East area of Portugal, in the Sierra Nevada Massif (Spain) and in Greece. In particular, crystalline rocks are also widespread in Calabria and a high percentage of these rocks is present in the Sila, Serre and Aspromonte Massifs. Fresh or weathered crystalline rocks, highly fractured, may be affected by deep-seated landslides due to the presence of tectonic structures, which may predispose and control the landslide mechanisms. The Serra di Buda landslide, near the town of Acri (Cosenza), can be included among the deep-seated landslides which affect weathered crystalline rocks. Starting from the geological model, the analysis of the geotechnical data (digital terrain model, borehole logs, piezometer levels, superficial and deep displacements, geomaterial characteristics, etc.) allows to detect the uncertainties inherent the elements that concur to define the geotechnical model. To reduce some of these uncertainties a calibration by means of numerical modelling is carried out, and the results obtained show the usefulness of this approach.

The paper aims at checking the contribution that DInSAR data, processed via different algorithms, can provide to the analysis of damages recorded to buildings located in slow-moving landslide affected areas. For this purpose, an urban area in Calabria region, southern Italy, was selected due to the availability of both DInSAR data since 1992 and historic information concerning damage data recorded via municipal ordinances. The combination of DInSAR data and the results of supplementary damage surveys allowed the preliminary investigation of a cause (maximum velocity)—effect (damage) relationship which, once validated, can be valuably used for damage analysis and forecasting.

Rainfall-induced shallow landslides involve several geo-environmental contexts and different types of soils. In clayey soils, they affect the most superficial layer, which is generally constituted by physically weathered soils characterised by a diffuse pattern of cracks. This type of landslide most commonly occurs in the form of multiple-occurrence landslide phenomena simultaneously involving large areas and thus has several consequences in terms of environmental and economic damage. Indeed, landslide susceptibility zoning is a relevant issue for land use planning and/or design purposes. This study proposes a multi-scale approach to reach this goal. The proposed approach is tested and validated over an area in southern Italy affected by widespread shallow landslides that can be classified as earth slides and earth slide-flows. Specifically, by moving from a small (1:100,000) to a medium scale (1:25,000), with the aid of heuristic and statistical methods, the approach identifies the main factors leading to landslide occurrence and effectively detects the areas potentially affected by these phenomena. Finally, at a larger scale (1:5000), deterministic methods, i.e., physically based models (TRIGRS and TRIGRS-unsaturated), allow quantitative landslide susceptibility assessment, starting from sample areas representative of those that can be affected by shallow landslides. Considering the reliability of the obtained results, the proposed approach seems useful for analysing other case studies in similar geological contexts.

Deep-seated mass-movements of different types affect the Pizzotto–Greci slope in northwest Calabria, Italy. The slope is carved out of phyllitic rocks capped by gneissic layers. Its geological structure is extremely complicated by tectonic structures that pervasively cross the slope transversely and downslope. A large-scale gravitational deformation of sackung type affects the slope. On the upslope side a debris-flow source area feeds a large fan constructed by recurrent debris-flow deposits. Aggradation is consequently occurring along the stream at the base of the slope. In order to define the internal structure of the slope for a stability slope model, geological, geostructural, geomorphological, historical and dendrogeomorphologic studies, as well as direct geotechnical logs and indirect geophysical investigations have been carried out over a two-year project financed by the EC Environment Programme. The main aspects of the geological and geomorphological studies and some preliminary geotechnical data are presented here, along with a conceptual model aimed at describing the relationships between the mass-movements on the slope and the construction/destruction stages of the fan at the base of the slope. The model is based on the assumption that aggradation has a stabilising effect on the slope, thus debris-flow activity is reduced and, consequently, destruction of the fan occurs, bringing the slope again towards unstable conditions. The reactivation of mass-movement, however, leads to the reconstruction of the fan and the buttressing effect at the base of the slope is restored. Thus, the process is cyclic and self-regulating.

This paper illustrates the compilation of an engineering geological map based on structural architecture and weathering grade of crystalline rocks occurring in the central-western portions of the Mucone River basin (Sila Massif, Calabria, Italy). The map, drawn at 1:10,000 scale and covering an area of about 100 km2, was compiled by combining new geological and structural data with the results of a weathering-grade field survey. Five weathering classes, each characterized by comparable mechanical behaviour, have been mapped, from the class VI (residual and colluvial soils) to class II (slightly weathered rock). Both qualitative and semi-quantitative criteria (e.g. rock colour, discolouration processes, samples broken by hand and hammer, sound of the rock when it is struck by a geological hammer, Schmidt Hammer tests) were used to distinguish and map weathering-grade classes at outcrop scale. The thematic map presented in this paper aims to provide a useful tool for land planning policy, for the evaluation of geological and geotechnical hazard and for environmental and engineering perspectives of land use.

The work deals the monitoring of a single ancient landslide detected in the Vonace area, southwards of Maierato (Calabria, Italy). A 18-hour-measurement campaign has been carried out using the Ground-based Synthetic Aperture Radar (GBSAR) interferometry technique carried between March, 25th and 26th. Displacement maps have been geolocated and overlaid to a Digital Elevation Model of the scene. It has been observed that the Vonace area is almost stable except two portions located at the foot of the ancient landslide and at the centre of the town, respectively. In both cases, a maximum displacement of about 0.5 mm has been measured. A further campaign is needed to confirm this displacement.

The field monitoring is an essential tool to define geotechnical model able to assess landslide stability conditions, with particular reference to the hydrological response of the slopes in presence of widespread landslide events — the occurrence of several landslides trough wide areas. The results relative to two sample sites, representative of study areas characterised by homogeneous geological elements and where field monitoring has been carried out for adequate time intervals, are illustrated in the paper. In particular, we consider an area with outcroppings formed by a sort of “melange structure” made up of blocks and fragments of phyllites, clays, shales, ect., in a prevalently clayey matrix (Lungro sample site), and an area where are present rocks and soils deriving from weathering of crystalline rocks (“Serra di Buda”, Acri, sample site). In the Lungro sample site a piezometer monitoring network and a rain gauge give indications about the hydrological response of the slopes in an urban area; in the “Serra di Buda” sample site the piezometer levels measured for a long time period, and the rainfall, permit to identify some relationships between the cumulative rainfall and the piezometric levels. Values of cumulative rainfall of about 700 mm on 120 days represent a necessary, but not sufficient, condition for critical stability conditions in the considered sample sites, in relation to possible scenarios of widespread landslide events.

I movimenti in massa (frane e instabilità dei versanti) contribuiscono in maniera rilevante ai processi geologici che fanno vivere il nostro Pianeta, governandone la sua evoluzione spazio-temporale. I fattori che predispongono il territorio ai movimenti in massa variano nel tempo, così come variano le forzanti climatiche, che costituiscono le più frequenti cause di innesco delle frane. Nel contesto richiamato la conoscenza dei movimenti in massa, l'individuazione di strategie di prevenzione del rischio e la definizione di interventi di prevenzione, dovrebbero positivamente confrontarsi con le emergenze prodotte da eventi di franosità, per trarne i migliori risultati in termini di prevenzione. La nota fornisce dunque alcuni spunti di riflessione, prendendo come riferimento alcune emergenze che hanno interessato il territorio della Calabria, per individuare un approccio, semplice e condivisibile da tutti i Soggetti interessati, che consenta di trarre i migliori risultati in termini di prevenzione dei movimenti in massa partendo da una gestione efficace e sostenibile delle emergenze.