Wide-area ground deformation monitoring in geothermal fields in western Turkey

The large-scale production and injection of geothermal fluids induce pressure, volume, and temperature gradient changes in the subsurface, which may result in surface deformation as well. Interferometric synthetic aperture radar (InSAR) is a promising utility for monitoring ground surface deformation and inferring subsurface reservoir operations that are difficult to observe directly. This study provides the first wide-area InSAR-derived long-term ground deformation across major geothermal fields in western Turkey. It aims to identify ground deformation hotspots within the geothermal exploitation sites and analyze their relationship with energy production and pumping. In the present study, the whole 2014–2020 Sentinel 1-A and 1-B SAR archive available over the region along ascending and descending orbits was processed using the persistent scatterer interferometry (PS-InSAR) technique. Compaction and land subsidence hot spots caused by fluid withdrawal are found within the geothermal fields. The results indicate that the observed systematic surface subsidence deformation result from the increase of geothermal production during the observation period in western Turkey. The real-time power data of geothermal plants retrieved from the transparency platform of the Turkish energy exchange are related to surface deformation. We estimated the drainage area of the production wells using subsidence deformation, caused by pore pressure decline in the reservoir. The results provide supporting evidence for the systematic monitoring and identification of deformation patterns in spatial-temporal extend can reveal reservoir dynamics and compartments, which are crucial for reservoir characterization and field development plan.