Abstract

This paper presents the first comprehensive high deformation map for the Mosul dam which is located on the Tigris river in the western governorate of Ninawa, North West of Iraq from 2014 to 2016. This map generated from space-based multi-pass differential SAR interferometry (DInSAR) measurements which reveal that parts of the dam are undergoing rapid subsidence. (DInSAR) technic has been applied to review the vertical surface movement (movement of the dam body to downward), because an interferogram provides information about height variations present on the imaged surface Furthermore, the information obtained from phase difference in an interferogram can be adjusted to compensate for topography, resulting in information that can be related to very small relative movements of the dam body (centimeter or millimeter scale). Three datasets of SAR images, provided by sentinel 1A Mission, are acquired from October 16, 2014, November 28, 2015 and February 08, 2016. DInSAR data show a subsidence rate largely located within of the Dam body, with a subsidence rate from about 7–14 mm/yr within the period 2014–2015. Also, DInSAR data show a subsidence rate largely located within the Dam body for the period between 2015 and 2016 and a subsidence rate from about 9–20 mm/yr. This result encourages us that DInSAR which is successor of sentinel 1A/SAR that allows measuring surface and dam’s deformations up to millimetre accuracies and must be more useful tool for detecting and monitoring dam subsidence on long time scales when used in conjunction with geotechnical measurements and other geologic information.

Keywords: Sentinel 1A; DInSAR; Interferometry; Subsidence; Geotechnical