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.
