Abstract Problem: One of the most important problems in Iranian cities is their vulnerability toward natural hazards, such as earthquakes and storms. This is particularly critical in the old part of cities due to the poor conditions of the physical structure of these areas, considering factors such as the quality of materials, lower permeability and a lack of renovation. Due to its geographic position, Iran is always under threat from earthquakes. According to official statistics, %6 of the human causalities in Iran have resulted from earthquakes during the past 25 years, and on average, an earthquake with magnitude of 6 on the Richter scale occurs every year, while an earthquake with a magnitude of 7 strikes the country every ten years. The most recent earthquake with 6.8 degree magnitude on the Richter scale hit the city of Bam in 2003 and caused large losses of human life. Such statics indicate the importance of appropriate planning to reduce the financial and human damage caused by earthquakes in Iran. Purpose: We aim to identify the most highly deteriorated areas within the old and new regions of the city of Sanandaj using GIS and relating techniques. We also attempt to recognize the main reasons causing these deterioration problems. Methods: To this end, we first conceptualize eleven physical-spatial factors. These factors are analyzed using fuzzy logic and IHPW (Inverse Hierarchy Process Weight) within GIS. Results and conclusions: The results of the model as applied to the structures of the city of Sanandaj illustrate that a fuzzy approach is a basic tool that can be used to identify vulnerability. Its application to the problem assists in unifying relevant theories and practices. It also generates maps of vulnerable points that may be more adaptable to changes and can greatly assist planners and policy makers in decision making.
