Land subsidence assessment under excessive groundwater pumping using ESA Sentinel-1 satellite data: a case study of Konya Basin, Turkey

Land subsidence analysis using satellite imagery is a consequential subject. Earth scientists have begun utilizing satellite imagery as an alternative to in-situ measurements and conceptual models. Synthetic aperture radar (SAR) images, moreover, utilize the reformer approach more than traditional satellite imagery with the use of high-resolution radar images. As a natural hazard, land subsidence is mostly attributed to excessive groundwater extraction, which is also the main reason for choosing the Konya Plain in Turkey as the study area for the present work. Since the Konya region is an agricultural and industrial land, groundwater extraction has been a challenging circumstance for the last few years. Change in groundwater level is also correlated with land subsidence rates through hydrogeological conceptualization. In this study, SAR images of the Sentinel 1 satellite are utilized for land subsidence rate calculation with the European Space Agency's SNAP software. Differential SAR interferometry (DInSAR) technique was used, which makes possible to detect deformation on the ground surface of the same portion of the Earth's surface using SAR images. The different acquisitions with DInSAR method allow to create differential interferograms that provide information ground motion with accuracy in cm. Three periods were utilized as 2016-2017, 2017-2018 and 2018-2019 the mean land subsidence rates were calculated for each period as 2.2, 1.4 and 1.7 cm/year, respectively. In the sum of the 3-year period, the maximum subsidence value went up to 16 cm.