Estimation of Seismic Vulnerability of Urban and Rural Housing in Iran regions by Using Skeletal and Materials Used

Damage to residential buildings is one of the most important physical damages of an earthquake that can cause further damages. The main question in this study is "How much is the vulnerability of residential units in country regions base of materials and skeleton as well as earthquake risk?" The main purpose of this study is to investigate the level of seismic vulnerability of residential units in Iran regions. The methods used in the research are AHP-fuzzy, DIMETEL-fuzzy and spatial analysis. The findings of the study show that there are many differences between the regions and the urban and rural areas regarding the vulnerability of residential units to earthquakes. The mean score of vulnerability in urban areas were 0.27 and in rural areas were 0.31, which indicates high vulnerability of rural areas in comparison with urban areas. Regionally, cities in Markazi, Hamedan, Isfahan, Tehran, Kurdistan, Gilan and Zanjan provinces are in good condition in terms of urban housing vulnerability while cities in eastern, southern, southwest and northwestern regions of the country are highly vulnerable. In rural areas, Markazi, Isfahan, Tehran, Kurdistan and Gilan provinces are more appropriate than other provinces and the eastern, central, southern and western provinces are also highly vulnerable.

Earthquake hazard is one of the most important natural hazards that annually cause a lot of damage to countries in the world. Identifying physical and structural vulnerability levels (one of the important aspects of vulnerability) of human settlements before of earthquake play a significant role in preventing and managing hazard and reducing costs. . Due to the geographical location of Iran and locating on the earthquake belt, there have always been major earthquakes throughout history. Destructive earthquakes such as Bojin Zahra earthquake in 1962, Roodbar earthquake in 1990, Bam earthquake in 2003, Varzaqan 2012, Kermanshah 2017 were the examples of destructive earthquakes in Iran during the last 60 years. The main purpose of this study is to evaluate the seismic vulnerability of housing in Iranian cities with regard to materials and skeleton type as well as seismic hazard.

AHP-fuzzy and DEMATEL-fuzzy are the methods that used in this research to assess the housing vulnerability in Iran regions. The study area in this study was the Shahrestans(one of the administrative regional division) of Iran in 2016 and the data used in this study were the type of materials and skeletons of residential buildings in 2016 and the seismic hazard map of Iran.

 For analyze urban and rural housing physical data after the formation of GIS data bank, in the first stage, estimate the vulnerability of urban and rural housing building in Iranian regions regardless of seismic risk base on type of materials and The skeleton using the expert opinions. In the second stage, seismic hazard estimation in Iranian regions was done using seismic hazard map and seismic hazard rate was calculated for each region. Finally, with integration of housing physical vulnerability and seismic hazard rate final vulnerability of housing in Iranian regions was obtained. Research findings are analyzed in two sections: rural and urban housing. According to the findings, urban housing sector in the Markazi, Hamadan, Isfahan, Tehran, Kurdistan, Gilan and Zanjan provinces are in good condition but in the in the eastern, South, Southwest and Northwest regions are not in a good condition. In the urban housing sector, most of the regions (41 percent) in terms of vulnerability are very vulnerable (0 to 0.21). In the rural housing sector, the regions located in the central provinces of Isfahan, Tehran, Kurdistan and Gilan are more suitable than other regions, and those in the eastern, central, southern and western regions are high vulnerable. In the rural sector, the low vulnerability class (score of 0.20 to 0.27) with 39% of the regions had the highest percentage. The average score obtained in rural housing sector is 0.31 and in urban housing sector is 0.27, indicating higher vulnerability of rural housing to urban housing units. This situation is more severe in Isfahan, Semnan, Zanjan, Gilan, Kermanshah, Kordestan and Chaharmahal -Bakhtiari provinces than other provinces and this indicates more attention to urban housing Strengthening and less attention to rural housing Strengthening. Other regions with positive numbers are located in the provinces of West Azerbaijan, East Azerbaijan, Kerman, Yazd and Lorestan, which shows the attention of these provinces to Strengthening of rural housing units.

The results show that there is a great differences in the vulnerability of residential units between cities and rural in Iran regions. The difference between urban and rural sectors are the result of the weak policies and actions of the responsible organizations in rural housing. In general, due to the lack of proper budgeting structure and lack of proper policymaking in the ​​housing consolidation of Iran, most of the regions, especially in the rural sector, have major weaknesses which have led to the vulnerability of residential units. Research proposals are also presented in two sections: Future Research and Practical Suggestions. In the first part, considering that the area under study in this study is a region and some facts may not be properly represented due to the extent of the region level, the studies should be done at a smaller level such as the city and rural and in the second part It has also proposed the creation of a database for housing agencies.