Land subsidence characteristics of Ordos using differential interferometry and persistent scatterer interferometry

Land displacement in Ordos, China, between 8 January 2007 and 19 January 2011 was mapped using L-band ALOS PALSAR data. Twenty ALOS PALSAR scenes acquired were utilised to generate both PSI and DInSAR results. Several locations in the eastern Ordos experiencing rapid land subsidence were identified including Huo Luo Wan coalmine and Qu Jia Liang coalmine. The subsidence rates ranging from -35mm/year to 35 mm/year were detected. The comparison between PSI and DInSAR outcomes, although showing good agreement in general, reveals some gaps in PSI map near Qu Jia Liang coalmine mainly due to rapid changes within the four-year period. Six successive DInSAR results were exploited to generate time series deformation map, with selected points being analysed and the reason being given for the formation of gaps as well. The DInSAR deformation measurements were then converted into time series velocity maps and integrated with PSI outcome to generate a final product.