Abstract



The Shapur I rock relief at Naqsh-e Rostam, one of the prominent stone monuments of the Sasanian period, has undergone various forms of weathering and deterioration due to prolonged exposure to environmental factors and the intrinsic properties of its stone substrate. This study aims to identify the main factors affecting its deterioration, characterise the physical and mineralogical properties of the bedrock, and develop emergency conservation strategies based on systematic condition assessment. Terrestrial laser scanning and digital photogrammetry were used to document the relief and produce three-dimensional models, orthophotos, and damage maps. Petrographic, physical, X-ray diffraction (XRD), and X-ray fluorescence (XRF) analyses were conducted on stone samples, complemented by regional climatic data and systematic field-based damage mapping. The results indicate that the bedrock is a calcitic limestone with minor clay minerals, whose microstructural discontinuities and reduced compressive strength under saturated conditions increase its vulnerability to moisture-related deterioration and chemical dissolution. Climatic and environmental factors, particularly precipitation, surface runoff, freeze–thaw cycles, temperature fluctuations, biological activity, and atmospheric pollutants, contribute to the deterioration processes. Damage mapping revealed a non-uniform spatial distribution and local overlap of deterioration features, indicating the interaction of multiple deterioration mechanisms. Based on the condition assessment, an emergency conservation programme following the principles of minimal intervention and preservation of authenticity was developed. Recommended measures include controlled surface cleaning, consolidation of unstable areas, injection of compatible natural hydraulic lime grouts, stabilisation of microcracks, and limited filling of deteriorated areas where structurally necessary. The integration of digital documentation, laboratory analyses, climatic assessment, and systematic damage mapping provides a scientific basis for understanding deterioration mechanisms, prioritising conservation measures, and establishing a reliable baseline for long-term monitoring and preventive conservation of the monument.