عنوان مقاله [English]
Fuzzy logic is one of the technique that can be used to take into account the uncertainties existed in the phenomenon enter probabilistic or mathematical models. Fuzzy set theory was first introduced by (Zadeh 1965) who developed the concepts of classical sets. Information is obtained from data, measurement or past knowledge, approximation must often be made which is turn introduce uncertainties. Fuzzy expert systems are modeled capable of solve problem as well as expert human.
Earthquake phenomenon is one of the most destructive natural disasters that occur every several years and it caused vast human and financial losses. In such awfully status, it is necessary to investigate the different sight of the earthquake. Earthquake is a complex issue, which result from various variables that affect its occurrence, like seismic hazard assessment. Uncertainty, which is a result of vagueness and incompleteness of the data, should be considered in a rational way. Fuzzy logic can be modeled for two kinds of uncertainties (as low knowledge and human instrumentation and as lack of perspicuity in complex phenomenon), whereas seismic hazard assessment (SHA) face with many uncertainties, using fuzzy logic system can help us to take into account the uncertainty existed for solving problems. Fuzzy set Logic has been used in some earthquake studies (Lamarre and Dong 1986; Chen et al. 1988; Furuta 1993; Chongfu 1996; Wadia-Fascetti and Gunes 2000). Recently it was used to develop to control seismically vibrations of buildings (Kim et al. 2010), to the classification of seismic damages in buildings (Anaxagoras et al. 2003), to seismic signal discrimination between earthquakes and quarry blasts (Lassari et al. 2012).Iran is located in Himalaya-Alpine seismic belt, a destructive earthquake occurs every several years. Northwest Iran is situated between three seismic thrust belts; the Caucasus thrust belt from the North and the Zagros seismic belt from the South and the Alborz Mountain belt to the East, and has experienced many destructive earthquakes. The presence of active faults by different focal mechanism have produced high seismicity in this region, especially Tabriz is considered one of the most important and densely populated cities in the country with a population of more than 1.6 million people in this seismic zone.
The northwestern region of Iran has experienced devastating earthquakes in recent years, causing irreparable mortalities and financial losses, which can be mentioned. The 858-year earthquake in Tabriz, which was completely destroyed, was a 4 November 1042 earthquake that killed 40,000 people from and part of the city was completely destroyed and the earthquake of January 8, 1780, which was destroyed by the city of Tabriz, and the number of kills was about 50,000. (Ambraseys and Melville. 1982), As a result, the risk assessment in this area is necessary for a way that reduces uncertainties.