Settimio Ferlisi

One of the main challenge in the functioning of any society is the safety from natural hazard. Among these hazards, rainfall-induced flow-like phenomena (e.g. debris flows, debris avalanches or hyperconcentrated flows) are a fundamental threat to the socio-economic development. To succeed in the challenge of a safer society, it is necessary to implement risk management strategies aiming at enhancing the preventing capacity to the occurrence of the abovementioned phenomena. Referring to the case study of Campania region (southern Italy), one of the most at risk areas in Europe, this paper shows how the results coming from the analyses of historical incident data can be profitably used by Authorities in charge of the risk to life reduction in implementing/improving, at medium scale, suitable warning systems with a cost-effective use of financial resources

This paper shows the results of a research aimed at analyzing the susceptibility and hazard, at the source areas, of slope instabilities involving shallow deposits of pyroclastic soils and characterised by own triggering mechanisms. This goal is pursued – at large scale (1:5,000) – with reference to Mount Albino, a carbonatic relief prone to different types of rainfall-induced slope instabilities (i.e., hyperconcentrated flows, debris flows and debris avalanches) which threaten the municipality of Nocera Inferiore (Campania region, southern Italy). In particular, susceptibility and hazard analyses specifically deal with the hyperconcentrated flows and are carried out via the use of heuristic and deterministic procedures thanks to the availability of geological and geomorphological information as well as data on both stratigraphic settings and geotechnical characteristics of potentially involved pyroclastic soils. The results highlight the role played by the above predisposing factors along with the conditions characterising the boundary-value problem at hand on the triggering mechanisms whose proper modelling is fundamental for a suitable assessment of the source volumes which can be mobilized during critical rainfalls

The processing of data acquired by Synthetic Aperture Radar (SAR) with advanced methods based on multidimensional imaging opens new perspectives in the monitoring of facilities in built environment. The availability of data acquired by recent meter-resolution satellite SAR sensors allows precise monitoring of even single buildings and infrastructures, therefore valuably helping in the detection and monitoring of exposed facilities. This paper deals with the potentialities offered by the use of SAR data in the framework of the built environment monitoring by discussing results obtained by the processing of Cosmo-Skymed data.

This paper shows the results of a study aimed at quantitatively estimating—in terms of direct (repair) costs, at large scale (1:5000)—the slow-moving landslide risk to a road network assumed as undamaged as well as the consequences to the same network in damaged conditions. The newly conceived methodological approaches address some challenging tasks concerning (i) the hazard analysis, which is expressed in terms of probability of occurrence of slow-moving landslides with a given intensity level that, in turn, is established based on empirical fragility curves, and (ii) the consequence analysis, which brings to the generation of time-dependent vulnerability curves. Their applicability is successfully tested in a case study in the Campania region (southern Italy) for which both very high-resolution DInSAR data and information gathered from in situ surveys on the severity of damage sustained by the selected road sections are available. Benefits associated with the use of the obtained r...

With escalating costs of landslide risk mitigation and relief, a challenge for local authorities is to develop landslide risk mitigation measures that are viewed as efficient, feasible and fair by the many stakeholders involved. Innovative measures and the participation of stakeholders in the decision making process are essential elements in developing effective strategies to deal with the ever-changing spatial and temporal patterns of landslide risk. A stakeholder-led policy process, however, can face many social and economic challenges. One of the most difficult is deciding between costly protection measures or relocating homes. Particularly in areas with high population density, protection works are often not built because of economic/environmental constraints or private interests of the local residents. At the same time it not always possible to relocate households even if the costs are deemed less than protecting them. These issues turned out to be crucial in a recent participa...

ABSTRACT This paper demonstrates an innovative role for experts in supporting participatory policy processes with an application to landslide risk management in the Italian town of Nocera Inferiore. Experts co-produce risk mitigation options based on their specialized knowledge taking account of local knowledge and values by directly coupling stakeholder discourses with option design. Drawing on the theory of plural rationality and based on a literature review, interviews and a public questionnaire, stakeholder discourses are elicited on the landslide risk problem and its solution. Armed with the discourses and in close interaction with stakeholders, experts provide a range of technical mitigation options, each within a given budget constraint. These options are subsequently deliberated in the participatory process with the intent of reaching compromise recommendations for landslide risk mitigation. As we show in an accompanying paper, “Compromise not consensus. Designing a participatory process for landslide risk mitigation” (this issue), the provision of multiple co-produced policy options enhances stakeholder deliberation by respecting legitimate differences in values and worldviews.

The paper focuses on the behaviour of a model strip footing, resting on a saturated dense sandy soil, subjected to centred or eccentric vertical loading. Experimental tests, carried out on a small-scale physical model, are able to reproduce effective stress levels equivalent to those prevailing in prototype problems, thanks to the maintenance of a downward steady-state seepage in the soil. The test program consists of three series of tests, each corresponding to an imposed value of hydraulic gradient, and each involving five load eccentricities; one series, in particular, is carried out with still water. Relevant points of load–settlement curves are related to the evolution of soil-footing collapse mechanism, evidenced by the distortion of some vertical coloured sand strips. The collapse mechanism is formed either by one or two sliding surfaces, depending on both load eccentricities and hydraulic gradient values. Significant differences are shown to occur between centred and eccentric loading footing response. Shear strength parameters obtained from back-analyses carried out on load values recorded at the appearance of each sliding surface on the free soil surface, in both hypotheses of associated and non-associated flow rule validity, are adopted to draw, for each test, a theoretical collapse mechanism consisting, in plane strain, of a log-spiral line with adjacent-end tangents; the obtained theoretical sliding surfaces, in turn, are compared to the experimental ones, showing that these latter are either stress characteristic or zero-extension lines depending mainly on cumulative footing displacements and current effective stress level in the soil.

ABSTRACT Modern geomechanics approaches frequently adopt collapse interaction diagrams obtained from load tests carried out on small-scale footing models in order to describe the overall behaviour of footings under the combined action of inclined and/or eccentric loads. Collapse interaction diagrams are used as yielding relationships, in a plasticity theory formulation, for the “macro-element” formed by the footing and the resisting soil. The main theme of this paper is to explore the potential of an expert system, named adaptive network-based fuzzy inference system (ANFIS), to determine such interaction diagrams for predicting foundation behaviour, subjected to vertical centred and eccentric loads, starting from results of small-scale model experiments. The inference system is trained by the results of a series of load tests both in normal and “incremented” gravity conditions, to predict load–settlement curves for a footing of given size with an assigned value of the eccentricity ratio. Cluster analysis is used to support the proposed inference system in order to learn from any simulated load–settlement curve the points corresponding to the collapse mechanism occurrence. Predicted results compare favourably with tests results. The simulation model predicts convincingly the load–settlement curve, the settlement value at which collapse takes place as well as the different types of collapse mechanisms. The results encourage the use of ANFIS in supporting the optimisation of model testing program, since the proposed method allows the identification of the minimum number of tests needed for a good performance of the expert system, particularly when this is to be used in problem formulations of the inverse type: a few careful experimental tests can thus suffice in generating new responses of the investigated geotechnical system, corresponding to conditions not yet explored from an experimental standpoint.

ABSTRACT The main goals of the EU FP7 project ‘Living with landslide risk in Europe: assessment, effects of global change, and risk management strategies’ (or SafeLand, www.safeland-fp7.eu/) were to:provide policy makers, public administrators, researchers, scientists, educators, and other stakeholders with an improved harmonised framework and methodology for the assessment and quantification of landslide risk in European regions;evaluate the changes in risk pattern caused by climate change, human activity, and policy changes;provide guidelines for choosing the most appropriate risk management strategies, including risk mitigation and prevention measures.To fulfill the above goals, a Consortium of 27 partners from 13 European countries worked on a research programme organised into 21 Work Packages, with several work tasks under each of the Work Packages. The scientific development comprised 18 Work Packages, and to facilitate management of the Work Packages, these were grouped under five Resear ...