Envisat and Sentinel 1-A InSAR analysis of sinkhole subsidence in Hamedan, Iran

The purpose of this research is to access land subsidence and sinkhole deformation in Hamedan plain, Iran. In the past decades, due to excessive extraction of water from the underground resources, the water table in plain has dropped sharply. This has led to land subsidence and increased sinkhole occurrence in the area. We used interferometric synthetic aperture radar (InSAR) data from the Envisat and Sentinel-1 (S1) satellites to investigate land subsidence in Hamedan. The Envisat data covers a period from September 2003 to November 2007, while the S1 data covers a time period from November 2014 to March 2017. To derive the spatial extent of the deformation signal, we used a coherencebased small-baseline subset (SBAS) method and derived the time series of ground subsidence. The InSAR data analysis reveals up to approximately 20 cm of line-of-sight displacement over 4 years (2003-2007) and 7 cm over 3 years (2014-2017). The InSAR results are discussed in this presentation and are analysed against geological information and in-situ data to derive the relationship between the location of sinkholes and areas affected by land subsidence.