Physical Resilience of Buildings Against Earthquakes in the Earthquake-Affected Areas of Andika City

Introduction
Physical resilience is very low due to the high fragility of rural settlements in the face of conditions and limited capacity to deal with changes. Rural housing as an important part of man-made environment, generally in accidents that happen quickly, suffer a lot of damage, so it is important to pay attention to the provision of resilient housing, especially in areas where natural hazards have intensified. Also, it is very important to pay attention to the rural areas that seem vulnerable to disasters due to the weakness in facilities and socio-economic level.
The study area is Andika city. Andika city in Khuzestan province was hit by an earthquake with a magnitude of 5.7 and a large area in 2021, and this earthquake caused considerable damage to rural residential houses in this city. Also, in this earthquake, 600 residential units were damaged and more than 10 billion tomans cost of damage to housing in this city is estimated. According to the statistics and information obtained from the Rural Disasters and Crisis Unit of the General Administration of the Housing Foundation in Andika City and Khuzestan Province, out of a total of 552 inhabited villages in this city, 120 villages have been affected by accidents and suffered a lot of damage in the physical part, especially in housing, as for example in the village of Repi 100 houses have been completely destroyed. The studied villages are scattered in the central part, and they form the statistical population of the present study. According to the issues raised in the problem statement, the research question is raised as follows: At what level is the current state of houses of rural households in Andika city evaluated in terms of resilience?
Materials and Methods
In terms of its nature, this research is of the type of quantitative research, and in terms of its purpose it is of applied research, and in terms of the method it is descriptive-analytical. In the studied area, out of a total of 1726 rural houses in the city, 600 houses were damaged by the earthquake in 1400. In this study, villages were selected as samples, where the destruction of rural houses in the face of an earthquake was more than 20 units. Based on this, 9 villages that had the most damage caused by the earthquake in terms of housing were selected as sample villages. The sample size was calculated with the help of Cochran's formula, and with the help of the ratio sharing rule, the number of investigated houses in each village was determined. The total number of houses in the 9 surveyed villages was 256.
Results and Discussion
Due to its location on the earthquake belt, Iran has always been at risk of earthquakes. The formation of large faults and the presence of active stress fields have made Iran prone to earthquakes. In rural areas, due to the construction of non-standard houses, which is done due to various reasons such as incorrect government policies and economic savings, the houses are vulnerable to the risk of earthquakes. Therefore, it is very important to pay attention to the concept of rural housing resilience. In the context of earthquake management, resilience can be defined as the capacity of a system, potentially exposed to hazards, to adapt through resistance or change to reach and maintain an acceptable level of performance and structure. In the present study, the physical resilience of housing under 5 components with 36 indicators was investigated. According to the significant level obtained in all dimensions of the housing's physical resilience (except the spatial and structural dimensions), the mean is significantly lower than the theoretical mean and is evaluated at a low to medium level. Except for the spatial average with 3.24 and the structural dimension with 3.14, which is higher than the theoretical average (number 3), in other dimensions, the physical resilience of the villagers' housing is lower than the theoretical average and poorly evaluated. So that the averages of mental image dimension with 2.65, functional dimension with 2.74, and physical resilience structure of rural housing with 2.99 were lower than the theoretical average.
There is a significant relationship between all variables except the number of household members living in a residential unit with resilience structure. There is also an inverse relationship with weak intensity between the variables (duration of residence in the village, age of the respondents) and resilience. There is a weak direct relationship between the variable number of years of education and resilience. According to the significance level of 0.01, there is a significant direct relationship with medium intensity between the variable of average income and resilience. There is a significant relationship between housing characteristics and resilience, except for the variable of total infrastructure area. There is an inverse relationship with moderate intensity between the variables (building age, number of floors) and resilience; in such a way that with the increase of each of the variables, the resilience decreases and with the decrease of each of them, the resilience increases. The relationship between the variables (total area of the residential unit, number of rooms) and significant resilience is of a direct type with medium intensity. There is no significant relationship between individual characteristics and the structure of housing vulnerability. There is a direct and moderate relationship between the characteristics of the roads and the resilience of the houses. The type of loan received, the quality of the structure in terms of almond, semi-durable and low-durable, and the types of framing of the residential unit are effective on the physical resilience of the housing.