Recent estimates of crustal deformation and land subsidence in the Nile Delta, Egypt using GNSS-PPP datasets over 2012–2024

Abstract The Precise Point Positioning (PPP) technique has been utilized to process the Global Navigation Satellite Systems (GNSS) annual datasets at 24 stations in the Nile Delta region, Egypt from 2012 to 2024. The present study aims to present recent estimates of horizontal crustal deformation, vertical land movements, and the analysis of the International Terrestrial Reference Frame (ITRF) coordinate conversion between the two utilized ITRF frames in Egypt, namely ITRF2020 (epoch 2024) and ITRF2008 (epoch 2012). Based on the accomplished findings, it has been found that the land subsidence in the Nile Delta region ranges between −3.9 mm/year and 2.3 mm/year with an average of −1.5 ± 1.9 mm/year. Regarding the horizontal crustal movements, it is recognized that such crustal deformations vary between 25.8 mm/year to 27.6 mm/year with an average equals 27.0 ± 1.0 mm/year. In addition, the average direction of that deformation equals 38.6° ± 2.1°. Such results agree normally with those of other studies concerning the regional movements of the Nubia tectonic plate. The attained simple mathematical model describing the relationship between ITRF2024 and ITRF2008 frames shows that the average Cartesian displacement vector equals −0.312 m ± 0.026 m, 0.153 m ± 0.010 m, and 0.152 m ± 0.020 m in the X , Y , and Z directions respectively. Additionally, the velocities are −24 ± 2 mm/year, 12 ± 1 mm/year, and 12 ± 2 mm/year respectively.