ارزیابی فرونشست زمین مبتنی بر تناظر داده‌های تصاویر ماهواره‌ای راداری، افت آب زیرزمینی و کاربری اراضی

The expansion the exploitation expansion of growth water resources has caused the phenomenon of subsidence in some parts of Iran, especially the Mahyar Plain, Isfahan, and it has caused serious damage to infrastructure, agricultural land, and environmental damage. Identifying areas subject to land subsidence and estimating its rate plays an important role in managing and controlling this phenomenon. The technique of differential radar interferometry (D-InSAR) with very high accuracy is one of the most suitable methods for identifying and measuring the amount of subsidence. In this research, differential radar interferometric technique was used to identify and measure land subsidence in Mahyar Plain in the period from 2004 to 2010. For this purpose, 8 pairs of time series images from the ASAR sensor were used in the C-band of the radar in the ascending pass. The method used in this research is based on the laboratory-survey method. Survey data, land use maps, geology and information of observation wells in the region were used to validate the method. The results show that the maximum average annual subsidence rate in the region is about 6.4 cm. Also, the highest amount of land subsidence has occurred in the cultivated areas as a result of excessive water extraction and the drop in the level of the underground water table. The relationship between land subsidence and the amount of changes in the piezometric well level showed that for every 2 cm drop in the level of the piezometric well, the plain has subsided by 4 milimeter.