Locating a Temporary Housing Site for Earthquakes in the Cities (Case Study: Zahedan City)

Introduction Iran is among the top ten countries vulnerable to natural disasters (Amini, 2005), the most important of which is considered to be earthquakes. Located on the Alpine-Himalayan belt, this country has experienced 130 earthquakes with magnitudes of Mw 7.5 on the Richter scale during the past few centuries (Zangi Abadei, Mohamadeisafaei, & Ghaed Rahmati., 2008). Considering the fact that Iran has experienced the most severe earthquakes in the world four times, it can be acknowledged that the country bears a record of witnessing intense and destructive earthquakes. Furthermore, the highest frequency of the strongest earthquakes occurred following the 1980s also belongs to this country; four earthquakes of this sort have been recorded in Iran (Ozey, 2011). Meanwhile, due to their population density and structural aspects, the cities are of substantial importance in this regard; the occurrence of any incidents would pose numerous problems and result in several ravages. Yet, what must receive grave attention here is the inadequate provisions of the cities in handling the events following the earthquake. In this regard, urban management must be able to take control of the situation in the city and prevent further disarrays after the occurrence of disasters such as earthquakes. One of the effective strategies in this area is to consider temporary housing sites which has been investigated in the present study.
Methodology The present study was conducted through a descriptive-analytical method, the results of which are of practical features. In terms of structure, spatial and non-spatial (descriptive) data were used in this study. The required data were gathered using the results of general population and housing census conducted in 2011, comprehensive and detailed urban plans, and other findings related to the subject at hand. Data analysis in this study was carried out using the Analytical Network Process (ANP), Analytical Hierarchy Process (AHP), and the Topsis model within the settings of softwares including Super Decisions, Expert Choice, and ARC GIS. In order to select convenient locations for temporary housing, first, the necessary criteria were provided and then scored according to the experts’ views; using the ANP and AHP models, these criteria were weighted and the indices were prioritized via the Topsis model. Due to the spatial nature of the majority of data, the initial investigations were carried out in the GIS setting as the software is capable of analyzing and interpreting spatial information. Following the preparation of different layers using the geographical information system, it was attempted to locate a temporary housing site.
Results According to the latest earthquake risk zoning map and considering the presence of fundamental faults in Zahedan and Nehbandan, the former is located in an area with a relatively high risk of earthquakes; therefore, it is necessary to adhere to a basic acceleration of 0.3 gal in construction projects (Consulting Engineers Shahr-o-Khaneh, 2006). Six layers of population density, user compatibility, access to roads, health centers, police stations, and fire stations in the city were examined in the findings of the study, according to the effective criteria on locating temporary housing sites, and then, a map of convenient areas for this purpose were provided. Through an integration of these layers, a final, optimal map for locating temporary housing bases in Zahedan was presented and the open spaces in the city were modified on this map. Different distribution of population in the city, hence, the different population density in Zahedan, has led to a set of regions to be of suitable and relatively convenient conditions for constructing a temporary housing site, particularly in the Northern half of city. Moreover, in terms of the extent of land use adaptability with the construction of temporary housing sites, a large area of Zahedan city is of relative adaptability and a number of regions in the Southern and Northern parts of the city are completely adaptable. Also, in relation to the criterion concerning the distance to fire stations, a number of central, eastern, north-western, and western regions of the city are convenient for constructing these sites, whereas the southern and a part of north-eastern and eastern countryside are inconvenient for such purpose. Regarding the street network coverage, many regions of the city are suitable for temporary housing sites in general, while a number of problems exist in the north-eastern parts of the city and therefore, construction of a temporary housing site is not recommended in these regions. In terms of the distance from health centers, it can be stated that except for the southern and north-western regions which occupy a relatively great area, there are large parts in the city suitable for constructing these sites; however, in terms of the presence of police stations, extensive parts of the city lack the required condition for constructing temporary housing sites.
Conclusion Preparation prior to the occurrence of crisis in the cities is one of the most important issues which has attracted the attention of many urban planners and experts. Earthquake, one of the most significant factors in creating a crisis, is an important matter in the cities due to the scale of the effects it may bear and must receive special attention. According to the evaluations carried out in the present study, areas located in the central region of Zahedan city are convenient for constructing temporary housing sites. Additionally, the lands in the eastern parts of the city can also be used for such purposes. Going farther from the central regions of the city, there are less convenient places for constructing these sites; the north-western, north-eastern, south-eastern, and southern parts of the city are the least convenient for construction. The results of the study show that for the construction of temporary housing sites, areas of almost 310, 745, 2432, and 1205 hectares are inconvenient, inconvenient to relatively inconvenient, medium to relatively convenient, and convenient, respectively. For a more practical procedure in locating a site, it is recommended to identify the present open spaces, offices with open spaces in proper locations and with the necessary managements for operation during crisis as well as investigating residential spaces located in distressed areas.