Bateira, Carlos

Pereira, Susana da Silva

Silva, Márcio

English

Repositório Aberto da Universidade do Porto

Geophysical Research AbstractsVol. 13, EGU2011-13070-2, 2011EGU General Assembly 2011© Author(s) 2011Vulnerability Assessment of Buildings and Roads to Shallow TranslationalLandslides in Santa Marta de Penaguião, Vila Real, PortugalMárcio Silva (1), Carlos Bateira (1), and Susana Pereira (2)(1) Dynat, CEGOT, Oporto University, Portugal (marciofssilva@hotmail.com; carlosbateira@gmail.com), (2) RiskAM, CEG,IGOT, Lisbon University, Portugal (spereirageo@gmail.com)Landslides are among the most frequent geomorphologic processes in the planet and every year is considerablethe number of human lives lost and the economic consequences related to this phenomenon.According to the expression proposed by Varnes (1984), risk analysis and cartography combines three majorcomponents – the probability of occurrence of a certain phenomenon with a given magnitude, the identificationand valuation of the elements exposed to the process and, at last, the degree of loss that those elements areexpected to suffer (vulnerability).Following this idea, the concept of vulnerability can be defined as the degree of loss that the elements in risk areable to experience as consequence of a phenomenon with a particular magnitude (Glade et al., 2005). Essentially,vulnerability refers to the potential loss, damage or destruction of an element (Alexander, 2000).However, although landslide susceptibility and hazard studies are frequent and the identification of exposedelements can be reasonably easy to achieve, internationally few works have contemplated the spatial assessmentof vulnerability (Bell & Glade, 2004). Once the term vulnerability is defined and comprehended in many manners,the quantity of methods and variables selected to its analysis is equally extensive (Hufschmid et al., 2005).In fact, the difficulties inherent to data collection and the collaboration needed between different sciences expertsmake studies about vulnerability very expensive, time-consuming and hard to realize (Parise, 2001). This impassebecomes even more serious when it is assumed that quantitative risk assessments make possible the identificationof areas where are expected the most important losses and where the mitigation efforts should take place inorder to obtain the best harmony possible between cost and benefits (Remondo et al., 2008) in the occupation ofterritories.In this context, the present study, integrant part of the research project named “MapRisk”, focuses in thecontribution to the development of fixed elements vulnerability assessment to landslides, namely buildings androads.Taking as work field the council of Santa Marta de Penaguião (70 km2), localized in the Portuguese district of VilaReal, the main objectives that have structured this study were the identification of the different exposed elementsand the estimation of their vulnerability face to shallow translacional landslides.Considering the concept of vulnerability as the degree of loss of a certain element exposed, expressed in a scalebetween 0 (no loss) and 1 (total loss), resultant of the occurrence of a process with a certain degree of intensity,this assessment of buildings and roads vulnerability contemplated two vectors – the destructive capacity of thephenomenon and the constructive consistence of the exposed element. Based on these two components we havedeveloped the following formula which results in the classification of vulnerability for different structures: V =DC x (1 - CC)V – VulnerabilityDC – Destructive Capacity of the landslideCC – Constructive ConsistenceTo the area of Santa Marta de Penaguião is available the cartography of susceptibility to shallow transla-cional landslides conceived by Pereira (2009), equally during the “MapRisk” project. For the identification of theexposed elements and assessment of vulnerability we have mapped more than 8100 buildings and over 301 km ofroads, based in ortophotomaps dated from the year 2006.In this study we also resort to an intensive field research, creating a functional evaluation of almost every structurebuilt, considering its own characteristics (typology, building technique, major building materials, number of floors,state of conservation, . . . ); identifying the structures that are affected to civil protection services and distinguishingthe different types of roads existing in the study area.The main results of this study are the identification of the different elements placed in areas of high and veryhigh susceptibility to shallow translacional landslides and the assessment of their vulnerability, in function of theintensity expected for this kind of processes and the construction characteristics of the elements in study. The finalcartography produced with this work constitutes a contribute to the analysis of Santa Marta de Penaguião council,allowing to determine the structures that present the highest vulnerability levels face to shallow translationallandslides and providing an important instrument to the study and mitigation of the possible consequencesresultant of this risk.ReferencesAlexander, D., 2000. Confronting Catastrophe – New Perspectives on Natural Disasters. Oxford UniversityPress, Oxford, 282 pp.Bell, R. & Glade, T., 2004. Quantitative Risk Analysis for Landslides – Examples form Bíldudalur, NW-Iceland. Natural Hazards and Earth System Sciences, No 4: 117-131.Glade, T., Anderson, M. & Crozier, M, 2005. Landslide Hazard and Risk. John Wiley & Sons, Ltd, London, 802 pp.Hufschmid, G., Crozier, M. & Glade, T., 2005. Evolution of Natural Risk: Research Framework and Per-spectives. Natural Hazards and Earth System Sciences, No 5: 375-387.Parise, M., 2001. Landslide Mapping Techniques and Their Use in the Assessment of the Landslide Haz-ard. Physics and Chemistry of the Earth, Elsevier Science, Vol. 26, No 29: 697-703.Pereira, S., 2009. Perigosidade a Movimentos de Vertente na Região Norte de Portugal. Faculdade de Le-tras da Universidade do Porto. 370 pp. (Tese de Doutoramento).Remondo, J., Bonachea, J. & Cendrero, A, 2008. Quantitative Landslide Risk Assessment and Mapping onthe Basis of Recent Occurrences. Geomorphology, No 94: 496-507.Keywords:Vulnerability, Landslides susceptibility, Exposed elements.

Vulnerability assessment of buildings and roads to shallow translational landslides in Santa Marta de Penaguião, Vila Real, Portugal

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Vulnerability assessment of buildings and roads to shallow translational landslides in Santa Marta de Penaguião, Vila Real, Portugal

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