Simone Frigerio

A web-based platform for automatic and continuous landslide monitoring: The Rotolon (Eastern Italian Alps) case study

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. We design a multi-source and web-based platform for automatic and continuous monitoring.A user-friendly web interface allows a practical up-to-date solution for decision-makers.A better knowledge of the processes improves the quality of research.The framework is open and supported for custom requests.

Medium-Scale Multi-hazard Risk Assessment of Gravitational Processes

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, showing triggering factors (earthquakes, meteorological extremes), contributing factors, and various multi-hazard relationships. The second part of the section gives an example of a medium scale multi-hazard risk assessment for the Barcelonnette Basin (French Alps), taking into account the hazards for landslides, debris flows, rockfalls, snow avalanches and floods. Input data requirements are discussed, as well as the limitations in relation to the use of this data for initiation modeling at a catchment scale. Simple run-out modeling is used based on the energy-line approach. Problems related to the estimation of temporal and spatial probability are presented and discussed, and methods are shown for estimating the exposure, vulnerability and risk, using risk curves that expressed the range of expected losses for different return periods. The last part presents a software tool (Multi-Risk) developed for the analysis of multi-hazard risk at a medium scale.

RiskCity and WebRiskCity: Data Collection, Display and Dissemination in a Multi-Risk Training Package

Within the activities of the United Nations University, the ITC School on Disaster GeoInformation Management (UNU-ITC DGIM) at the International Institute for Geo-Information Science and Earth Observation (ITC) has developed WebRiskCity, an Open Source WebGIS platform for multi-risk assessment. The platform is a support to the RiskCity project, a GIS distance education course for multi-hazard risk assessment. The course has a guide book which gives the theoretical background behind the spatial data requirements for risk and hazard assessment procedures, generation of elements-at-risk databases, vulnerability assessment, qualitative and quantitative risk assessment methods, and risk evaluation. The architecture of WebRiskCity is based on a hierarchic structure similar to the original RiskCity dataset. Different switches for every component of the risk assessment have been defined, and through various menus, the user can select the options for each exercise. Tools for spatial analysis are implemented to compare maps at different scales and for on-line interpretations. A complete educational database was compiled, merging original layers of local authority and simulated data. The purpose of WebRiskCity is to be a tool of knowledge and education for risk assessment, as well as to provide a means of supporting non-academic staff, and non-governmental organizations and stakeholders, whose knowledge in risk management is vital, but often lacks a scientific base.

Assessing the Effect of Mitigation Measures on Landslide Hazard Using 2D Numerical Runout Modelling

Landslide mitigation measures are used to reduce the risk affecting mountain communities. The quantitative estimation of the change or reduction in risk, after implementing mitigation measures, requires modeling of past events and the forward prediction of possible future occurences. However, the forward-prediction of landslide hazard is subjected to uncertainties due to the lack of knowledge on some key aspects like the possible source volume that can be triggered and model parameters that determine the landslide runout. In this study, a back-analysis of a debris flow event was carried out using MassMov2D to create a set of parameter ranges for forward-predicting runouts with mitigation measures. We approached the issue of uncertainty by systematically sampling parameters from wide ranges and running hundreds of different runout scenarios. Simulations from back-analysis were compared with the forward-predicted models to determine changes in the spread and intensity of debris flows affecting elements at risk (e.g. houses and roads). This study is a first step towards a quantitative risk assessment (QRA) being carried out within the EC FP-7 funded CHANGES network (Grant Agreement No. 263953).

Evaluating data quality collected by volunteers for first-level inspection of hydraulic structures in mountain catchments

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.

The Rotolon Catchment Early-Warning System

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.

Landslide monitoring with an integrated platform: methodology, design and case study

Landslide monitoring is usually linked to a complex physical system with several parameters and uncertainties. Different instruments are located and set up on field, but a simple, continuous and efficient integration is compulsory for an acceptable warning support.The South-East flank of Mount Carega (Eastern Italian Alps) is affected by a complex landslide that, since 1985, is threatening Recoaro Terme. After the last re-activation on November 2010 (637 mm of intense rainfall recorded in the 12 days prior the event), a mass of approximately 320.000 m3 detached from the flank of Mount Carega and evolved into a fast debris flow that ran for about 4 km along the stream bed.A real-time monitoring system was required to detect early indication of rapid movements, potentially saving lives and property. A web-based platform for automatic and continuous monitoring was designed as a first step in the implementation of an early-warning system. Measurements collected by the automated geotechnical and topographic instrumentation, deployed over the landslide body, are gathered in a central acquisition unit. After the calibration process, data are transmitted by web services on a local server, where graphs, maps, reports and alert announcement are automatically generated and updated. All the processed information is available by web browser with different access rights.

Multi-scale debris flow vulnerability assessment and direct loss estimation of buildings in the Eastern Italian Alps

Abstract 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.

Hands-On Experience of Crowdsourcing for Flood Risks. An Android Mobile Application Tested in Frederikssund, Denmark

There is evidence that the toll of death and destruction caused by natural hazards is rising. This is often ascribed to the impact of climate change that resulted in an increased frequency of extreme meteorological events. As a consequence, it is realistic to expect that the casualties and damages caused by floods will increase in the near future. Advanced weather forecast is a fundamental tool to predict the occurrence of floods and structural mitigation measures are crucial for flood protection. However, these strategies should be associate with tools to promote and increase natural-disaster awareness and nonstructural mitigation measures in the exposed population. To bridge this gap, we coupled innovative, ICT-based technologies with crowdsourcing. The idea is to exploit geospatial data gathered by citizens and volunteers with their own devices such as mobile phones to provide authorities with relevant information in case of flood emergencies. This paper describes the design and testing of an Android application named MAppERS (Mobile Applications for Emergency Response and Support), thought to enhance active participation and response of the population in territorial and flood-risk mitigation in Frederikssund, Denmark. The results of the piloting fully validate MAppERS as an effective tool to support the decision-making process during a crisis and to improve the awareness of the community and their disaster resilience.

Ganderberg Landslide Characterization Through Monitoring

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.