Omid Nejadkazem - Academic staff, Department of Construction and Mineral Materials, Faculty of Electrical, Mechanical and Construction Engineering, Standard Research Institute, Karaj, Iran
Behzad Saeedi Razavi - Academic staff, Department of Construction and Mineral Materials, Faculty of Electrical, Mechanical and Construction Engineering, Standard Research Institute, Karaj, Iran

In real life situations this is rarely the case that everythins can be said about anything is either absolutely true or absolutely false. Zadeh suggested that it is possible to understand a statement as being 0.70 true. The use of fuzzy numbers and fuzzy sets offered the scietists powerful tools for performing classification and ranking tasks. This paper presents a system for assessing the risk of natural disasters, particularly under highly uncertain conditions, i.e. where neither the statistical data nor the physical knowledge required for a purely probabilistic risk analysis are sufficient. The theoretical foundation of this study is based on employing fuzzy set theory to complement the probability theory with an additional dimension of uncertainty. This would allow for expressing the likelihood of natural hazards by fuzzy probability.

Earthquake, Risk Assessment, Fuzzy logic