Long-term investigation of subsidence rate and its environmental effects using the InSAR technique and geospatial analyses

Abstract

Herein, we examined the subsidence occurring over two main plains for agricultural activities in Qom province in Iran using interferometric synthetic aperture radar (InSAR). ENVISAT-ASAR images from 2003 to 2010 and Sentinel-1A images from 2014 to 2019 were used to produce interferograms and mean velocity maps of subsidence in the line of sight (LOS) direction. Using the analyses in geospatial information science (GIS), the spatial correlations between areas with subsidence and water level drop and agricultural land-uses were explored. The results showed the mean velocity map which revealed 35 and 28 mm/yr of deformation going away in the LOS direction in Jafarabad and Qanvat plains, respectively, between 2003 and 2010 and higher subsidence rates between 2014 and 2019. Moreover, maximum subsidence occurred in the places that had not only a larger water level decline, but also a greater thickness of fine-grained sediments. Finally, the environmental effect of subsidence on the ground, infrastructures and water salinity was examined.