Urban subsidence detection using the sentinel-1 multi-temporal insar data

Abstract

This paper outlines the results of subsidence estimation over an urban area using Sentinel-1 data and Permanent Scatterer Candidate (PSC) Interferometric Synthetic Aperture Radar (PS-InSAR) technique. The study area selected is Chandigarh City (UT, India) and its near vicinities, which is located at the junction of three Indian states namely Punjab, Haryana and Himachal Pradesh. PS-InSAR is a well-established technique to identify and monitor the ground deformation using the satellite imagery. This technique has been extensively used for monitoring the earth surface deformations. Time series Sentinel-1 data comprising of 43 ascending images acquired during 2014 to 2017 over the study area have been used in this study. The high spatial and temporal resolution of this data allowed to carry out the time series analysis in an effective manner. Sarproz software package has been used for all PS-InSAR processing. The atmospheric phase screen (APS) of the SAR data has also been estimated and removed to minimise the noise in the estimated values. The results indicate the significant rate of the subsidence over the study area. The maximum rate of subsidence estimated is around -20 mm/year in specific locations. However, a large part of the study area showed a comparably low rate of subsidence. The possible cause for the high rate of subsidence in this area may be the depleting ground water levels in the region which also corroborates with the available literature. This study provides preliminary information on the probable danger to the urban infrastructure in the area.