relationships between different earthquake intensity scales in iran

intensity is one of the useful information in extract earthquake analyzing of a region; then, preparing a complete dataset of them is necessary for each region. one of the best intensity information of the most historical and several instrumental earthquakes in iran (from year 658 to 1979) was reported in an intensity scale with five degrees. there are also several earthquakes with reported intensity information in other three 12-degree intensity scales. intensity values of these earthquakes could be more useful, if they are converted to a uniform scale, especially in a recent 12-degree intensity scale. in this study, the intensity values were re-estimated for the earthquakes with different reports of intensity. these estimations were performed based on the definition of both the european macroseismic scale to consider the building damages and environmental seismic intensity scale to consider environment effects.orthogonal regression was also selected to estimate the relationships between different reported intensity scales (0.61 < σ < 1.80). by considering the results of the relationships of this study, the intensity values of iranian earthquakes with various intensity information, only descriptions, only intensity values, or both of them, could be re-estimated in a uniform intensity scale.