Uncertainties And Fuzziness In Analysing Risk Related To Natural Hazards: A Case Study In The Ortles Alps, South Tyrol, Italy
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A. Zischg, S. Fuchs & J. Stötter
Uncertainty and fuzziness in the input parameters needed for the determination of the collective risk induced by alpine natural hazards are investigated for the Sulden road between Prad and Sulden in the Ortles Area, South Tyrol, Italy. The road is the access road to the major skiing area in the Vinschgau region and has therefore a high importance for winter tourism. It is endangered by 17 snow avalanche paths. The determination of the collective risk on roads is based on the analysis of the fatality risk. In this work the uncertainties in the risk parameters were quantified using a normal distribution and a Monte Carlo simulation. Handling every imprecise parameter as a fuzzy number is another possibility to compute them with the operators of the fuzzy set theory and provides the consideration of uncertainties when managing risks. The use of fuzzy logic illustrated that the approximations of risk parameters could be represented transparently and systematically when vagueness associated with numeric quantities occurs. The uncertainties in the risk analysis have a significant influence on the subsequent procedures in risk management, i.e. risk communication processes. Therefore, the established method of risk analysis has been extended taking the uncertainties into consideration. Keywords: risk analysis, snow avalanches, roads, uncertainty, Monte Carlo simulation, fuzzy logic, natural hazards, Sulden, South Tyrol, Ortles Alps. 1 Introduction Roads in the Alps, during wintertime, are often exposed to snow avalanche hazards. As a consequence, most of these roads have to be closed temporarily or permanently. The analysis of the risk of demise resulting from snow avalanches is a useful instrument to quantify the avalanche risk. These ideas were first outlined in Wilhelm [1, 2]. Later, this approach has been standardised as a
risk analysis, snow avalanches, roads, uncertainty, Monte Carlo simulation, fuzzy logic, natural hazards, Sulden, South Tyrol, Ortles Alps.