ارزیابی آسیب‌پذیری بلوک‌های ساختمانی شهر کرمانشاه در برابر زلزله و مکان‌یابی محل اسکان موقت جمعیت آسیب‌پذیر

Introduction



The risk of natural hazards, particularly earthquakes, is a highly significant concern in urban environments. This issue has garnered increased attention in light of recent seismic activity in Iran. Within the framework of this study, the initial phase entails estimating the vulnerability map of the building blocks in Kermanshah metropolis, as well as determining the number of individuals at risk during an earthquake. Subsequently, the research identifies and introduces safe zones or suitable locations for accommodating the vulnerable population during such seismic events. To construct the vulnerability map of the building blocks, various factors have been taken into account, including the distance from fault lines, the structural integrity of the buildings, the strength of the building blocks, and the size of the infrastructure. Additionally, population data for Kermanshah city has been utilized to estimate the vulnerable population. In this study, a fuzzy inference system consisting of eighty one fuzzy rules has been employed in order to approximate the vulnerability map during an earthquake. Subsequently, through the process of thresholding on said vulnerability map, blocks at high risk have been identified and subsequently the total population residing within said blocks has been acquired. The subsequent segment of this investigation involves the utilization of distance maps derived from rivers, faults, high voltage power lines, electric substations, fuel stations, roads, hospitals, fire stations, and police stations. These generated maps have then undergone fuzzification, and the weight of the criteria employed has been assessed using the fuzzy hierarchical analysis process (FAHP). Subsequently, by applying the weight associated with each criterion to the corresponding map and merging the resultant maps, maps depicting the suitability of certain locations for housing the vulnerable population during an earthquake have been obtained. Finally, through an examination of the map indicating the appropriateness of locations, the most optimal inner-city and outer-city sites for individuals' lodging amid an earthquake have been chosen. The outcomes of the initial phase of this investigation demonstrate that no less than 65,110 individuals will sustain injuries in the occurrence of an earthquake with a moderate level of intensity. The outcomes of the subsequent phase likewise suggest that a region in close proximity to the central area of the city's western boundary is apt for accommodating the vulnerable populace in the event of an earthquake.



Materials and methods

In this research, the shape files of faults, rivers, urban roads, high voltage power lines, hospitals, police stations, fire stations, fuel stations, building blocks and urban places such as: location of schools and educational centers, rescue and rescue centers, clinics and clinics, shelters, Basij offices and bases, etc. of Kermanshah city were used.

In this research, to prepare the vulnerability map of building blocks, the vulnerability criteria were first fuzzified. Then, using Matlab software, a fuzzy inference system was designed based on the Mamdani inference system with 81 fuzzy rules, and by defining the input and output membership functions, the vulnerability map of building blocks due to earthquake was obtained. Finally, by combining this map with the population density map, the amount of vulnerable population was estimated. Also, in order to prepare the map of accommodation sites, all the maps related to location were fuzzy using ArcMap software, then a weight was assigned to each of the maps, and finally, by overlapping the maps, the suitable places for the construction of the sites were determined



Results and discussion

In this research, an inner-city site and an outer-city site were identified for accommodating the earthquake victims. There are 151 places available in the proposed inner-city accommodation site during the earthquake that can be used. These places include: schools and colleges, green spaces, parks and gardens, hospitals, clinics and medical centers, administrative and organizational centers, service centers such as parking lots, terminals, etc. It was found that the total area of habitable places in the inner city site is over 978 thousand square meters. If the estimated population of vulnerable people in moderate and severe earthquakes are 65,110 and 448,282 people, respectively, a space of 15.02 square meters and 2.18 square meters can be allocated for each vulnerable person. In other words, if an earthquake with moderate strength occurs during the day, the density of vulnerable people in the proposed sites inside the city will be approximately 7 people per 100 square meters. Also, if a strong earthquake occurs during the night, the density of vulnerable people in the proposed sites inside the city will be approximately 46 people per 100 square meters, which is a high value, and for this reason, it is recommended that if the earthquake is strong and the number of people affected It is more likely that the proposed out-of-town site, which is near the inner-city site, should be used at the same time.





Conclusion

In this research, a method based on the fuzzy inference system for estimating the vulnerability of building blocks during an earthquake and estimating the vulnerable population, as well as locating safe points for housing the vulnerable population of Kermanshah metropolis, was introduced and described. The output results of the vulnerability map of building blocks show that the middle and western building blocks are in better conditions than other building blocks due to their distance from the northern and southern faults and the high strength of their structures, and they are less damaged in case of an earthquake. Considering the vulnerable population during an earthquake, it is necessary to secure and renovate blocks that do not have sufficient strength against earthquakes.

In the topic of safe places for earthquake victims, the factors of distance from faults and proximity or access to the hospital have the highest degrees of importance according to experts in the field of crisis management and the Red Crescent. In this regard, construction near existing faults should be strictly avoided. Also, the location suitability map produced shows that the area which is close to the middle of the western border of Kermanshah city is suitable for housing the vulnerable population during an earthquake, and this area is suggested as an urban site during an earthquake. And in case of an increase in the affected population, the injured or other displaced people should be accommodated in the out-of-town site by establishing a field hospital.