ite selection for Temporary Earthquake Shelter Compounds, Using Analytic Hierarchy Process and Weighted Linear Combination based on GIS; Case Study: Shahrood



Abstract

Natural disasters are unpredictable and unavoidable and their occurrence in human settlements has led to catastrophes in many cases. Therefore, it is necessary to prepare prior the occurrence of these events. A prompt response can be a solution to this goal. As long as assurance is provided to the affected population that there is no lack of assistance and facilities, their ability to return to pre-disaster conditions and recovery will be increased. Selecting the right accommodation according to the needs of people after natural disasters, as well as planning to meet the needs of the victims, not only reduces risks and expedites recovery operations during reconstruction, but also strengthens the protection structures and advances the safety aspects of communities prior to any kind of incident. Increasing concerns arising from high occurrence of natural disasters, especially earthquakes, and witnessing the unpleasant consequences, will emphasize the need for proper habitation conditions and facility provision. Iran is a country that is prone to disasters. In fact, no country in the world is immune to natural disasters. In this research, urban areas of Shahrood located in Semnan Province, have been studied with regard to seismic potential and proximity to the southeastern part of Alborz Mountain and Shahrood’s faults as a sample for selecting appropriate post-earthquake shelters. The overall purpose of this research is to propose a decision making process for efficient and safe spatial planning in the wake of crises. In the first step, the structural vulnerability of buildings in terms of foundation quality and their vulnerability measures is estimated at 24% of the city, which is equivalent to 12778 buildings prone to destruction, even facing a mild earthquake. After analyzing the possible damage to the city, according to the average household size of 3.43 people in Shahrood, 43829 people are estimated to be homeless. The amount of space needed to accommodate these people, with an estimated per capita of 30-45 square meters per person, was estimated at 132 to 198 hectares, which could be used in a few distinct and scattered spaces. After determining the area needed for settlement, the criteria influencing the location of temporary shelters were identified based on scientific literature and analysis of previous experiences. According to these studies, the criteria for influencing this concept are classified into nine groups including access, location, cultural, economic, compatible and incompatible neighbors, infrastructure conditions, land quality as well as space area. The subsets of these nine criteria can be categorized into two groups: constraint factors and classification possibilities. Factors such as distances from faults, high voltage electric power lines, vulnerable zones, gas stations and chemical storage facilities are known to cause limitations. The concept of the facility in this research, in addition to proximity to residential areas, main roads and storage depots, includes access to compatible applications, medical centers, security centers, fire departments and outdoor spaces; hence it is necessary to accommodate people at the minimal distance from these facilities. Parameters such as area, surface water, infrastructures and available energy sources are some of the criteria that need to be measured in terms of their quality in proposed options and decisions are to be made on the basis of their existence and accuracy. Since each parameter has a different effect on the location of temporary accommodation therefore, the list of priorities is sorted accordingly. In this article, a methodology for locating shelter after an earthquake has been recommended by using hierarchical analysis, weighted linear combination and GIS. In this multi-criteria decision-making process, the weighting process was performed on each parameter by paired questionnaires that were provided to 40 experts, and analyzed according to the principle of hierarchy (AHP) and arranged in Expert Choice software. Then, all of the data layers in GIS software were combined with WLC method according to the criteria and standardization. The Geographic Information System (GIS) has been used as one of the most useful tools in allocation and land use planning. To analyze the data in the software, after converting the data into the Raster structure and classifying the layers in appropriate categories and in accordance with the functional radius, a conclusion was made in the Arc GIS environment. The output, obtained by overlapping the collected items, is a list of land plots suitable for post-disaster shelters, sorted according to the aforementioned priorities.



Keywords: site selection, temporary sheltering, AHP, WLC, GIS