Monitoring ground subsidence in Jiaxing region using Envisat data

Abstract

Jiaxing is 110 kilometers far away from Shanghai, the high speed railway and the planed maglev from Shanghai to Hangzhou cross Jiaxing city. It is very important to monitor ground subsidence in Jiaxing region for the safe running of the high speed railways. However, the traditional ground subsidence measurement methods, such as precise leveling and GPS, have a very low spatial resolution and are laborious. DInSAR technology is a new effective method for monitoring ground subsidence with high resolution and accuracy, but due to the influence of many kinds of noises, the interferograms cannot reveal ground deformation directly. In this work, small baseline subset (SBAS) method is applied to extract the ground subsidence information. SBAS can reduce the effects of topographic error and spatial decorrelation, and also increase the number of useable InSAR pairs. Totally 13 scenes of the Envisat SAR images covering Jiaxing region between 2008 and 2009 are chosen and processed. The results show that a funnel shaped ground subsidence appears at Pinghu city.