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Land subsidence in Changzhou city (China) detected by C-band SAR dataset

Changzhou, China has been undergoing significant land subsidence along with over exploitation of groundwater for many years. In order to warn of the subsidence disaster, it's urgently necessary to obtain the detail information of land subsidence in Changzhou. In this paper, a spatial-temporal analysis about land deformation was adopted with the help of SBAS-InSAR method. C-band Envisat ASAR dataset acquired during 2004 to 2012 was used to unveil the spatial and temporal variations of land subsidence. The InSAR-derived land subsidence was compared to land deformation levelling survey and groundwater table data at wells. The comparison result between InSAR result and levelling survey data indicated that the SBAS-InSAR method can monitor land subsidence in a large area with high accuracy. Correlating groundwater table and multi-band InSAR measurements at groundwater-well stations showed that with the rise of the water table, the land rebounded. Our study provides scientific evidence on the management of groundwater extraction and the assessment of land-subsidence hazards.