Modelling land subsidence and fault reactivation due to groundwater pumping in the Alaşehir-Sarıgöl sub-basin, Turkey.

The Gediz river basin in Turkey (GBS) and its Alaşehir-Sarıgöl sub-basin (ASSB) are highly valuable for agriculture due to the presence of river sediments. Heavy agricultural irrigation has resulted in significant water stress in ASSB, leading to reduced groundwater levels, aquifer compaction, and land subsidence. It is important to note that there are primary and secondary faults present in ASSB as well. Tectonic movements have a significant impact on the ASSB area. Sentinel-1 SAR images taken between 2016 and 2020 have revealed significant subsidence in ASSB, with maximum rates of over 5 cm/year, affecting both urban and agricultural land use. And land subsidence is associated to earth fissuring in the Alaşehir-Sarıgöl plain. This research aims to investigate the relationship between pressure changes, land subsidence, and fault reactivation in the absence of tectonic plate movements. The displacement fields in the studied region over the past decade have been simulated using the GEPS3D simulator, a three-dimensional FE-IE geomechanical model developed at the Dept. ICEA, University of Padova.