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Anthropogenic problems threatening major cities: Largest surface deformations observed in Hatay, Turkey based on SBAS-InSAR

Anthropogenic problems threatening major cities: Largest surface deformations observed in Hatay, Turkey based on SBAS-InSAR

Authors
Şükrü Onur KARACA, Gültekin ERTEN, Semih ERGİNTAV, Shuhab D. KHAN

Keywords
Multi-temporal InSAR, Radar interferometry, Surface deformation, Hatay-Güzelburç, Turkey.

Abstract

The surface deformation caused by tectonic activities and anthropogenic factors poses a great threat to cities worldwide. The investigation and monitoring of these deformations are crucial in order to create risk analysis for the future. The problem in this case is to investigate the surface deformations and their negative effects caused by groundwater use and to identify possible landslide areas. In this study, the surface deformations in Hatay province were analyzed using SBAS-InSAR. The results from these analyses were evaluated by field observations. Sentinel-1 descending (183 datasets) and ascending (147 datasets) track geometries were selected to determine the surface deformation and its temporal evolution. Both east-west and vertical surface deformations were calculated, and the surface deformation profiles, surface 3D models and time series were created. These time series were associated with monthly precipitation data. The deformation area was interpreted with regard to available well-log data and geological setting of the study area. As a result of the study, a surface deformation resembling a bowl like structure was observed in the industrial zone located in the city center of Hatay-Güzelburç. The deformation rates are approximately 22.3 cm/year in the form of subsidence, 3.6 cm/year in the form of eastern movement and 10.1 cm/year in the form of western movement. The deformation of this bowl-like structure decelerated in the winter and accelerated in the summer due to excessive water use. The average monthly precipitation dataset supports these results. The stratigraphic data from water wells and the presence of limestone outside the eastern boundary of the deformation area show a thick clay layer in the eastern block of the bowl-shaped deformation structure. The difference between these two units, which causes a sharp anomaly at the eastern border of the deformation area, is interpreted as a probable normal fault.  The second study area where surface deformations are observed is the landslide zone. The deformation was found to be 7.5 cm/year in a westward direction and 1.5 cm/year as subsidence.

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