ارزیابی نقش عوامل جغرافیایی در تخریب محوطه‌های باستانی (مطالعۀ موردی: موساسیر رَبَط در شهرستان سردشت)

Abstract
The ancient site of Mosasir, located in Rabat in Sardasht county, is one of the most important historical-cultural centers, and is exposed to natural and anthropogenic dangers according to field surveys and studies. Therefore, this research addresses the problem of preventing its destruction and ensuring its preservation. The implementation of protection programmes is contingent upon prior assessment of the vulnerability of ancient sites. Accordingly, the main goal of the research is to investigate and analyze the role of effective natural factors (slope, land use, geology, rainfall, elevation and distance from the fault line) in the process of protecting versus destroying the ancient site of Mosasir. ArcGIS software was used to prepare the data for these factors, and the TOPSIS model was used to rank them. Weights and the relative importance of each criterion were determined through pairwise comparisons by eight academic experts using the AHP model in Expert Choice. According to the results, the ancient site of Mosasir falls into the low-vulnerability category, and the factors of elevation, slope and distance from the fault line had the greatest effect on its potential destruction. Owing to the region’s exposure to rainfall and the proximity of the Zab River to the site, precipitation, and consequently an increased likelihood of flooding, can further exacerbate destructive processes. Considering the concordance of the TOPSIS and AHP results with field reality in the study area and a consistency index value of 0.09, it can be concluded that the zoning map of geographical factors produced with these models constitute a scientifically sound tool suitable for local authorities.
Keywords: ArcGIS Software, TOPSIS Model, Mosasir Ancient Site.
 
Introduction
An increasing number of ancient sites and structures are in danger of being lost. Once destroyed, these resources are lost forever, together with irreplaceable cultural heritage and scientific data. In addition to misguided tourism practices, historical monuments and places can also be affected by natural phenomena. The principal concern addressed by the present study is the protection of ancient sites and the identification of factors responsible for their destruction. One such site shown by investigation and field studies to be exposed to both natural and anthropogenic threats is the Mosasir site, located in Rabat, Sardasht. To date, more than 13,000 historical objects have been recorded in this area. Historic monuments and sites in cold- and temperate-mountainous regions, such as Sardasht, are at risk owing to heavy rainfall, vegetation growth, sediment compaction and removal, road construction, and similar processes. Therefore, it is necessary to identify environmental factors to reduce or arrest degradation, while quantifying the impact of each factor. Thus, the main goal of this study is to investigate the role of natural factors and processes in the protection or destruction of ancient sites, with an emphasis on the Mosasir ancient site. The central research question is: which geographical factors are effective in destroying the ancient site of Mosasir? We hypothesised that, among the natural factors, rainfall and flood events play the most important role in the destruction of ancient sites in the Sardasht region. ArcGIS software was used to prepare the datasets for these factors and the TOPSIS model was employed to prioritise them. Weights and relative importance for each criterion were obtained from eight academic experts via pairwise comparison in the AHP model using Expert Choice.
 
Identified Traces
According to the TOPSIS model results, height, slope, and distance from the fault line (in that order) exert the greatest influence on the destruction of ancient sites. An inspection of the fault-line boundary map for the study area indicates that most locations lie at very short distances from the fault. Sardasht city likewise occupies a mountainous setting, with the elevation of the majority of its sectors at or above 1000 meters. This topographic situation renders the region one of the areas particularly prone to natural hazards. Conversely, rainfall and flooding are also among the principal agents driving the deterioration of ancient sites. River sediment load depends on topography, climatic parameters such as precipitation, and basin erodibility, all of which control the quantity of sediment delivered to terminal basins. Erosion and sediment accumulation are manifested directly as reductions in soil fertility and land loss, the infilling of dam reservoirs, increased turbidity of river waters, and broader environmental degradation. Consequently, given these points and considering that the study area occupies a position relatively favorable to rainfall and that the Zab River runs close to the historical site of Mosasir, precipitation can amplify destructive and damaging processes. Thus, the research hypothesis is corroborated. Furthermore, owing to Harb’s strategic siting on the eastern bank of the Zab Koch River, it is plausible that Sargon passed through this region during military movements; Harb Hill and its environs constitute one of the most important historical-cultural centers, particularly in the first millennium B.C. Situated between the Urartian and Assyrian polities, some site destruction in the area may derive from such conflicts. Therefore, we recommend further investigation into the destructive effects of human factors on these related ancient sites.
 
Conclusion 
The erosion of ancient monuments and buildings has been the subject of many studies, but in our country relatively few measures are taken to preserve and maintain them. Given the agreement between the TOPSIS and AHP outputs and field observations in the study area, and the consistency index of 0.09, we conclude that the zoning map of geographical factors produced by these models provides a scientifically robust solution suitable for authorities. Furthermore, the use of modern satellite imagery and high-spatial-resolution aerial photographs for the detection of ancient artifacts and the retrieval of archaeological information can substantially assist future research and enhance knowledge of the past.