Radar Interferometry-Based Investigation of Land Subsidence in Shiraz Plain Using ENVISAT ASAR C-Band Data: A Case Study of the South Zagros Region- Iran

 Land subsidence is the gradual or sudden downward movement of the earth's surface, often resulting from the extraction of groundwater, minerals, or hydrocarbons. This phenomenon, which can cause significant structural damage and environmental degradation, is increasingly prevalent in regions with excessive groundwater abstraction. The primary objective of this study was to assess subsidence in Shiraz Plain, using radar interferometry to analyze ground deformation due to groundwater depletion and other environmental factors, such as droughts and historical lake bed conditions.

  This study employed ENVISAT ASAR C-band radar images from 2007-2009 to investigate subsidence patterns in the Shiraz Plain. The images were processed using ENVI5.3.1 software with the SARscape plugin, including interferometry, ADAPT filters, and Goldstein filtering to mitigate errors and improve image quality. The final phase-to-displacement conversion and geocoding steps resulted in subsidence maps, which were used to analyze displacement across different regions. The data were validated by comparing the generated subsidence maps with field observations.

 The analysis revealed subsidence rates ranging from -14 cm to +5 cm, with the most significant displacements observed in the southeast of Shiraz and parts of Beiza. Ground displacement in urban and agricultural areas was also notable, with an average subsidence rate of -3.5 cm. The primary causes of subsidence in these regions were identified as excessive groundwater extraction, historical lake bed conditions, and geological factors such as fault zones.

The study highlights the importance of sustainable groundwater management to mitigate subsidence risks, and recommends continued monitoring and implementation of water conservation strategies to prevent further ground displacement in the region.