Modelling the rainfall-induced mobilization of a large slope movement in northern Calabria
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Two recent phases of mobilization of a large, rainfall-induced debris slide are analysed in terms of relationships between rains and phases of displacement. The first activation at San Rocco (San Benedetto Ullano, Calabria) occurred on 28 January 2009, after extraordinary rains had stricken the region for a couple of months. Detailed geomorphologic field surveys, combined with measurements of superficial displacements at datum points, were performed to properly recognize the evolution of the phenomenon. In addition, a real-time control system of rains and superficial displacements measured at extensometers was implemented, to better analyse the evolution of the phenomenon. In early May 2009, the activity reduced to very slow displacements, persisting in the same condition for the following 8 months. On 1 February 2010, premonitory signs of a new phase of activation were noticed, again following 2 months of extraordinary rainfalls. After few days of further precipitations, the middle sector of the landslide activated since 11 February, disrupting the road network and threatening the major lifelines and some buildings. A hydrological analysis aimed at simulating the dates of activation and the main phases of acceleration of the phenomenon was carried out, by calibrating the empirical model FLaIR against the daily rainfalls and the history of known phases of mobilization since 1970. Calibration allowed to successfully simulate both the cited phases of activity of the San Rocco landslide, by predicting the beginning of the movements as well as the following paroxysmal stages, as testified by the measurements at datum points and extensometers. The set of parameters obtained through calibration reflects the influence of both prolonged antecedent rains, and of high-intensity rainfalls of shorter duration, which slightly preceded the major displacements. Once calibrated the model, a suitable threshold could be defined, by analysing the trend of the mobility function against the history of activations of the considered slope movement, and by excluding false alarms. Accordingly, a reliable tool for predicting the phases of activity of a large slope movement could therefore be obtained.
KeywordsRainfall-induced landslide Geomorphological survey Superficial displacements Hydrological modelling
Authors are grateful to S. L. Gariano for drawing some of the illustrations and to the anonymous referees who helped through precious suggestions to improve the original manuscript. The study was partly funded by the Administration of San Benedetto Ullano. The in situ monitoring system was implemented by the Advanced Devices S.p.A.
- Amodio Morelli L, Bonardi G, Colonna V, Dietrich D, Giunta G, Ippolito F, Liguori V, Lorenzoni S, Paglionico A, Perrone V, Piccarreta G, Russo M, Scandone P, Zanettin Lorenzoni E, Zuppetta A (1976) L’arco calabro–peloritano nell’orogene appenninico–maghrebide. Mem Soc Geol Italy 17:1–60 (in Italian)Google Scholar
- Campbell RK (1975) Soil slips, debris flows and rainstorms in the Santa Monica Mountains and vicinity, Southern California. U.S. Geol. Survey, Professional Paper 851, 51 ppGoogle Scholar
- Capparelli G, Tiranti D (2010) Application of the MoniFLaIR early warning system for rainfall-induced landslides in Piedmont region (Italy). Landslides. doi: 10.1007/s10346–009–0189–9
- Cascini L, Versace P (1988) Relationship between rainfall and landslide in a gneissic cover. In: Bonnard C (ed) Proceedings of V international symposium on landslides, 10–15 July, Lausanne, Switzerland. A. A. Balkema, Rotterdam, The Netherlands, pp 565–570Google Scholar
- CASMEZ (1967) Carta Geologica della Calabria, F.229IIINE “Lattarico” (in scale 1/25000). Poligrafica & Carte Valori, Ercolano (Napoli), Italy (in Italian)Google Scholar
- Iovine G, Iaquinta P, Terranova O (2009) Emergency management of landslide risk during Autumn–Winter 2008/2009 in Calabria (Italy). The example of San Benedetto Ullano. In: Anderssen RS, Braddock RD, Newham LTH (eds) Proceedings of 18th World IMACS Congress and MODSIM09 Int. Congress on Modelling and Simulation, pp 2686–2693Google Scholar
- Iovine G, Lollino P, Gariano SL, Terranova O (2010) Coupling limit equilibrium analyses and real-time monitoring to refine a landslide surveillance system in Calabria (southern Italy). NHESS 10. In: Iovine GGR, Huebl J, Pastor M, Sheridan MF (eds) special issue on “approaches to hazard evaluation, mapping, and mitigation”. doi: 10.5194/nhess-10-1-2010
- Ramesh MV (2009) Real-time wireless sensor network for landslide detection. In: The third international conference on sensor technologies and applications. SENSORCOMM 2009, Athens/Glyfada, Greece, 18–23 June 2009, pp 405–409Google Scholar
- Sirangelo B, Versace P (1992) Modelli stocastici di precipitazione e soglie pluviometriche di innesco dei movimenti franosi. In: Proceedings of XXIII Convegno Nazionale di Idraulica e Costruzioni Idrauliche, Firenze, Italy, III, pp D361–D373 (in Italian)Google Scholar
- Sirangelo B, Versace P (1996) A real time forecasting for landslides triggered by rainfall. Meccanica 31:1–13Google Scholar