Simone Frigerio

The recent Sentinel-1 mission, started by the European Space Agency in April 2014, provides the scientific community with new capabilities for the monitoring of the Earth surface. In particular, the Terrain Observation by Progressive Scans imaging technique used in the Interfero-metric Wide swath acquisition mode permits to acquire data over very wide areas (250 km of swath extension) at 20-m spatial resolution, with 12-day revisit time, making it suitable for ground displacement monitoring applications. With more than 1 year of synthetic aperture radar images available , it is now possible to carry out monitoring activities of slow moving phenomena such as landslides at both regional and local scales. In this work, the potential of Sentinel-1A for the monitoring of shallow (from 2 to 6 m of depth) landslides occurring in the NorthEastern Italian Pre-Alps was tested. Two stacks of Sentinel-1A scenes acquired in both ascending and descending orbits were processed using the Permanent Scatterer Interferometry (PSI) technique. The results, analysed in terms of PS density and quality, were compared with the ERS-1/2 and ENVISAT PSI database available from the Italian National Cartographic Portal to assess the capabilities of Sentinel-1A in detecting and monitoring landslides in respect to the previous satellite missions. The results of this work show the great potential of Sentinel-1A in the continuous monitoring of landslide-prone territories even at local scale. The achievable results can provide information that is useful to delineate the spatial and temporal evolution of landslides and precisely assess their rates of deformation.

This paper presents a prototype of an interactive web-GIS tool for risk analysis of natural hazards, in particular for floods and landslides, based on open-source geospatial software and technologies. The aim of the presented tool is to assist the experts (risk managers) in analysing the impacts and consequences of a certain hazard event in a considered region, providing an essential input to the decision-making process in the selection of risk management strategies by responsible authorities and decision makers. This tool is based on the Boundless (OpenGeo Suite) framework and its client-side environment for prototype development, and it is one of the main modules of a web-based collaborative decision support platform in risk management. Within this platform, the users can import necessary maps and information to analyse areas at risk. Based on provided information and parameters, loss scenarios (amount of damages and number of fatalities) of a hazard event are generated on the fly and visualized interactively within the web-GIS interface of the platform. The annualized risk is calculated based on the combination of resultant loss scenarios with different return periods of the hazard event. The application of this developed prototype is demonstrated using a regional data set from one of the case study sites, Fella River of northeastern Italy, of the Marie Curie ITN CHANGES project.

Vulnerability assessment, as a component of the consequence analysis, represents a fundamental stage in the risk assessment process because it relates the hazard intensity to the characteristics of the built environment that make it susceptible to damage and loss. The objective of this work is to develop a quantitative methodology for vulnerability and loss assessment of buildings exposed to debris flows and apply it to a study area in NE Italy at local and regional scale. Using existing conceptual models of vulnerability and loss, this paper seeks to identify solutions for maximizing the information gained from limited observational damage data and a heterogeneous building data set. Two vulnerability models are proposed: Model 1 is based on the generation of empirical vulnerability curves using observed intensities; Model 2 takes into account multiple resistance characteristics of buildings and uses modeled debris flow intensities. The process intensity descriptor in both cases is debris flow height. The vulnerability values obtained with the local (Model 1) and regional (Model 2) models are further multiplied with the building value to calculate the minimum and maximum loss for each building in the study area. Loss is also expressed as cumulative probability calculated with Model 1 using a Monte Carlo sampling technique. The methodology is applied in the Fella River valley (northeastern Italian Alps), a region prone to multiple mountain hazards. Uncertainties are expressed as minimum and maximum values of vulnerability, market values and loss. The results are compared with relevant published vulnerability curves and historical damage reports.

ABSTRACT A Deep-seated Gravitational Slope Deformation (DGSD) extends over an area of 3.75 km2 in the south-west flank of Mt. Ganderberg, north of Bolzano, Italy. The landslide stretches from an altitude of 2,330 m a.s.l. down to the River Passer at 1,170 m, with an estimated shear surface depth of 100 m. The area is characterized by typical Alpine morphological features and preserves traces of the last glaciation and clear evidences of recent gravitational phenomena. The DGSD induced some collateral mass movements such has rotational and translational slides. Since 2007 the DGSD has been monitored through a network of 20 Global Navigation Satellite System (GNSS) benchmarks. The results showed a different rate of displacement, between the north and the south sectors that allowed to define the kinematics patterns of the landslide, a key point to forecast future scenarios and to support risk managers and public administration in the definition of the countermeasures for risk mitigation.

Abstract According to the aim of the CHANGES network, an EU funded project, research is carried out towards the improvement of the emergency management strategies for hydro-meteorological hazards under the effects of climate and the pressure of socio-economic changes. Aim supported on the need to enhance local resilience to these hazards under different scenarios, if possible by means of a multi-disciplinary and multi-hazard approach. Both requirements recognized on the scientific and practical community. In this context, ...

This section discusses the analysis of multi-hazards in a mountainous environment at a medium scale (1:25,000) using Geographic Information Systems. Although the term 'multi-hazards' has been used extensively in literature there are still very limited approaches to analyze the effects of more than one hazard in the same area, especially related to their interaction. The section starts with an overview of the problem of multi-hazard risk assessment, and indicates the various types of multi-hazard interactions, such as coupled events, concatenated events, and events changing the predisposing factors for other ones. An illustration is given of multi-hazards in a mountainous environment, and their interrelationships,

Profiling the potential destructive events that could occur in a study site, inventorying the assets (social and economic features) and estimating the physical effects due to the impacts are the basic issues for defining indicative risk scenarios. Moreover, the necessity of sharing and accessing available information is one of the most important component of risk management. GIS activity, modeling and analysis can improve results and scientific development, but most of end-user and disaster reduction components does not ...

Where and when a potentially damaging event will occur is one of the most important topics of discussion in the scientific community. As a matter of fact, landslide area will contribute to identify the vulnerable elements potentially affected by the event of a given magnitude and the degree of physical damage and the economic loss. Knowledge of the area and the time of occurrence, related to the triggering factors, permits to apply in advance an «early warning» system and related procedures to manage the crisis phase, according to Civil ...

In the Small Dolomites group (Eastern Italian Alps), the Rotolon catchment is affected by a landslide that historically threatened the nearby village of Recoaro Terme. After the last re-activation on November 2010, the need to deploy devices to monitor deformations on the unstable slope became of paramount importance. This paper deals with the methodology, the techniques and the integrated services adopted for the design and the realization of a web-based platform for automatic and continuous monitoring of the Rotolon landslide. The choice of a web environment simplifies data collection, while a remote control permits technical maintenance and calibration on instruments and sensors in the field. Data management is straightforward on a single server, with the dataset being continuously updated. There is a user-friendly web interface which allows a practical up-to-date solution for decision-makers. This web-based monitoring platform represents the first step in the implementation of a complete early warning system.

Within Mountain Risks Project, a methodology targeted to manage critical hydrogeological events is presented, taking advantage of GIS tools, decision support systems (DSS), and mobile technology. The methodology is settled and tested in a local Mountain Consortium of Municipalities (Lombardy Region, Italy), an area characterized by a high level of hydrogeological hazard and risk in a complex social and economic context. Initially, a landslide susceptibility and hazard assessment was performed to geographically define ...

The geomorphological change detection through the comparison of repeated topographic surveys is a recent approach that benefits greatly from the latest developments in topographical data acquisition techniques. Among them, airborne LiDAR makes the monitoring of geomorphological changes a more reliable and accurate approach for natural hazard and risk management. In this study, two LiDAR digital terrain models (DTMs) (2 m resolution) were acquired just before and after a complex 340 000 m3 landslide event (4 November 2010) that generated a debris flow in the channel of the Rotolon catchment (eastern Italian Alps). The analysis of these data was used to set up the initial condition for the application of a dynamic model.

The comparison between the pre- and post-event DTMs allowed us to identify erosion and depositional areas and the volume of the landslide. The knowledge of the phenomenon dynamics was the base of a sound back analysis of the event with the 3-D numerical model DAN3D. This particular code was selected for its capability to modify the rheology and the parameters of the moving mass during run-out, as actually observed along the path of the 2010 debris flow.

Nowadays some portions of Mt. Rotolon flank are still moving and show signs of detachment. The same soil parameters used in the back-analysis model could be used to simulate the run-out for possible future landslides, allowing us to generate reliable risk scenarios useful for awareness of civil defense and strategy of emergency plans.

Volunteers have been trained to perform first-level inspections of hydraulic structures within campaigns promoted by civil protection of Friuli Venezia Giulia (Italy). Two inspection forms and a learning session were prepared to standardize data collection on the functional status of bridges and check dams. In all, 11 technicians and 25 volunteers inspected a maximum of six structures in Pontebba, a mountain community within the Fella Basin. Volunteers included civil-protection volunteers, geosciences and social sciences students. Some participants carried out the inspection without attending the learning session. Thus, we used the mode of technicians in the learning group to distinguish accuracy levels between volunteers and technicians. Data quality was assessed by their accuracy, precision and completeness. We assigned ordinal scores to the rating scales in order to get an indication of the structure status. We also considered performance and feedback of participants to identify corrective actions in survey procedures. Results showed that volunteers could perform comparably to technicians, but only with a given range in precision. However, a completeness ratio (question/parameter) was still needed any time volunteers used unspecified options. Then, volunteers' ratings could be considered as preliminary assessments without replacing other procedures. Future research should consider advantages of mobile applications for data-collection methods

Severe instability processes have affected the Rotolon catchment (Eastern Italian Alps) for long time. The first written proof of a landslide occurrence dates back to 1798. The last re-activation occurred in November 2010 when, after a cumulative rainfall of 637 mm in 12 days, a mass of approximately 320,000 m3 detached from the unstable slope and evolved into a debris flow that ran for about 4 km along the channel, threatening the villages along the stream. Since then, the design and the implementation of an early-warning system was considered of primary importance, in order to mitigate the risk for the valley inhabitants. A monitoring network consisting of 42 topographic benchmarks and 6 wire extensometers was installed and a warning system was deployed along four sections of the channel. The latter consists of 3 pendulum sections and a trip-wire section. Alarm sirens installed near the settlements are activated when the warning system is triggered by a debris-flow event, guaranteeing some minutes lead time to the local population. In this way the inhabitants could evacuate in time and reach safe areas thus reducing the risk. A Decision Support System (DSS) is also integrated with the deployed sensors, therefore technicians may support crisis response with a user-friendly instrument.

A large DSGDS (Deep-Seated Gravitational Slope Deformation) which extends on an area of 3.75 km2 affects the southwest flank of Mount Ganderberg some 40 km north of Bolzano. The gravitational sagging of the slope is generating a wide field of tension cracks in the crown area where a rock slab of about 800.000 m3 shows clear precursory signs of possible detachment.
In 1401 a rock avalanche detaching from the same area dammed the Passer River thus creating a 35 m deep lake which through sequential breaching caused many casualties in the villages downstream. Using geomorphological survey and historical analysis it was possible to estimate the volume of the landslide deposit in 2 × 106 m3.
In this study the historical event is back-analyzed using the 2D code DAN-W in order to select the proper soil parameters to use in the modelling of the present potential rock avalanche. Then a 3D modelling is carried out using DAN3D software to evaluate the run-out scenario and the shape of the natural dam. Owing to the relevant discharge of the Passer River, a 2 × 106 m3 lake might be quickly filled. This can cause the breaching and subsequent collapse of the landslide dam with great risk and potentially heavy damages for the downstream population.

Il lavoro proposto rientra tra le attività svolte all’interno del Progetto Marie Curie Mountain Risks (Contract number MCRTN03598). L’attività ha considerato la crescente interferenza e sovrapposizione di eventi naturali sia come fattori innescanti sia per le conseguenze a effetto domino. Le classiche metodologie di analisi modellistica per singola tipologia di processo vengono integrate sempre più frequentemente in sistemi Multi-Hazard, dove i fenomeni non sono semplicemente sovrapposti ma vengono considerati per diverse potenziali nuove interazioni. Il sistema di validazione ne risulta conseguentemente modificato. L’attività ha portato alla realizzazione di un prototipo di piattaforma MultiRISK, basata su un modulo Modelling, di modellazione integrata, e un modulo Visualization, per una concreta analisi da parte di esperti dei risultati proposti, mediante semplici servizi web. Gli step operativi hanno dunque come obiettivo quello di offrire un completo sistema di modellazione ma allo stesso tempo una chiara strategia di comprensione e utilizzo del dato prodotto.

As part of the capacity building activities of the United Nations University - ITC School on Disaster Geo-Information Management (UNU-ITC DGIM) the International Institute for Geoinformation Science and Earth Observation (ITC) has developed a distance education course on the application of Geographic Information Systems for multi-hazard risk assessment. This course is designed for academic staff, as well as for professionals working in (non-) governmental organizations where knowledge of disaster risk management is essential. The course guides the participants through the entire process of risk assessment, on the basis of a case study of a city exposed to multiple hazards, in a developing country. The courses consists of eight modules, each with a guide book explaining the theoretical background, and guiding the participants through spatial data requirements for risk assessment, hazard assessment procedures, generation of elements at risk databases, vulnerability assessment, qualitative and quantitative risk assessment methods, risk evaluation and risk reduction. Linked to the theory is a large set of exercises, with exercise descriptions, answer sheets, demos and GIS data. The exercises deal with four different types of hazards: earthquakes, flooding, technological hazards, and landslides. One important consideration in designing the course is that people from developing countries should not be restricted in using it due to financial burdens for software acquisition. Therefore the aim was to use Open Source software as a basis. The GIS exercises are written for the ILWIS software. All exercises have also been integrated into a WebGIS, using the Open source software CartoWeb (based on GNU License). It is modular and customizable thanks to its object-oriented architecture and based on a hierarchical structure (to manage and organize every package of information of every step required in risk assessment). Different switches for every component of the risk assessment course have been defined and through various menus the user can define the options for every exercise. For every layer of information tools for querying, printing, searching and surface analysis are implemented, allowing the option to compare maps at different scale and for on-line interpretations.

Profiling the potential destructive events that could occur in a study site, inventorying the assets (social and economic features) and estimating the physical effects due to the impacts are the basic issues for defining indicative risk scenarios. Moreover, the necessity of sharing and accessing available information is one of the most important component of risk management. GIS activity, modeling and analysis can improve results and scientific development, but most of end-user and disaster reduction components does not have a high level of this background knowledge. In disaster risk management the capacity of quickly actions for planners, administrators, engineers, end.-users, architects, technicians, etc... is one of the most important matter. For this reason the best way to proceed was the possibility to create user-friendly instruments and devices, based on a geographical platform to share available information and supply requisite activities. In the work it was proposed a CartoWeb solution as a simple and ready-to-use open-source Web-GIS instrument (based on GNU License) as well as a convenient framework for building advanced and customized applications, following the necessity of disaster management experts. It is highly modular, customizable for its object-oriented architecture and based on hierarchical structure (to manage and organize blocks of information of each step required and used in risk assessment). Different switches for every package has been defined and more kind of menu and organization types of data has been structured (susceptibility map and vulnerable element with related data at different scale); for every layer many tools of query, printing, searching and surface analysis are improved, following the necessity to compare maps at different scale and for real-time interpretations. First goal of this activity was the comparison between a traditional GIS system to manage every information and an open source WebGIS platform; an user-friendly solution was provided and applied at local scale as testing issue, while next goal in future will be fit the structure with same switches of data to all municipalities of the study area and implement WMS connections to existing services for data sharing. With this kind of technique the capacity to access to other data packages and sharing updated information will increase (cadastrial maps, buildings maps, personal data, available resources in case of event, etc...). The study site is a Mountain Consortium of Municipalities (Valtellina di Tirano, Lombardy Region) located in Northern Italy. In particular, the village of Tresenda (municipality of Teglio) was chosen as a test-site among "critical" zones in the entire study area: it is a highly susceptible/hazardous area with the presence of vulnerable elements. A local risk scenario was pointed out, in which prospective direct damage has been assessed.

Many regions worldwide are threatened by multiple natural hazards with the potential to cause high damages and losses. However, the modeling of multiple hazards in a joint analysis scheme is still in the early stages of development as a range of serious challenges emerges in the multihazard context such as differing modeling approaches in use for contrasting hazards; the time- and data-demanding conduct of each single preparative, intermediate and analysis step; and the clear visualization of the modeling outcome. Under consideration of these difficulties, a regional multihazard exposure analysis concept is developed for five natural hazards: debris flows, rock falls, shallow landslides, avalanches, and river floods, complemented by a visualization scheme to present the modeling outcome. An automation of the two schemes resulted in a beta version of the MultiRISK modeling and the MultiRISK visualization software tool forming together the MultiRISK platform. To test the analysis scheme and the software implementation of MultiRISK a case study is performed in the Barcelonnette basin in France with a worst-case parameterization of the models on the basis of extensive literature reviews. Experiences from this case study offered many insights into the multihazard topic and even more questions, e.g. with respect to coherent multihazard model parameterization, validation or the comparability and interpretation of single-hazard modeling results, respectively. Although analysis schemes can be proposed and software tools can be provided to facilitate many steps, a well-conceived and reflective approach to multihazard settings is essential. The worst-case analysis based on literature values apparently leads to an overestimation of the susceptible areas and the number of exposed elements. Nevertheless, depending on the data situation of an area, especially in areas without any information on past events, this approach may offer the determination of general hazard distributions, overlaps, and areas of potential risk without data-demanding calibration.► We developed a regional multi-hazard exposure analysis and visualization scheme. ► We implemented the schemes into the MultiRISK Modeling and the Visualization Tool. ► In a case study the software tools proved supportive and user-friendly.

More and better training is needed to identify
and prevent or mitigate risk presented by
natural hazards. Too often, the concept of
risk is misunderstood, and neither responders nor the
public may fully understand what is at issue here.
Clear terminology is the first line of defence. But, in
order to facilitate widespread sharing of information
and knowledge necessary for the development of reliable
and extensible solutions for dealing with risk, one
also needs to employ the web and its graphic communication
capabilities.

Perception has been identified as resource and part of the resilience of a community to disasters. Risk perception, if present, may determine the potential damage a household or community experience. Different levels of risk perception and preparedness can influence directly ...

... Affiliation: AA(Department of Geography and Regional Research, University of Vienna, Vienna, Austria (simone.frigerio@univie.ac.at)), AB(School and Observatory of Earth Sciences, Institute of Earth Physics, CNRS & University of Strasbourg, Strasbourg, France (jeanphilippe ...

Sterlacchini, S., Frigerio, S., Canziani, M., Poli, S., De Amicis, M., & Sironi, S. (2007). Proposta di una metodologia per la gestione di emergenze idrogeologiche nella Comunità Montana Valtellina di Tirano. Rendiconti della Società Geologica Italiana, 123-128.