remote sensing Article Ground Deformation Analysis of Bolvadin (W. Turkey) by Means of Multi-Temporal InSAR Techniques and Sentinel-1 Data Mumin Imamoglu 1,2,* , Fatih Kahraman 1 , Ziyadin Cakir 3 and Fusun Balik Sanli 2 1 Informatics and Information Security Research Center, TUBITAK, 41470 Gebze, Turkey;
[email protected] 2 Department of Geomatic Engineering, Civil Engineering Faculty, Yildiz Technical University, 34220 Istanbul, Turkey;
[email protected] 3 Department of Geological Engineering, Istanbul Technical University, 34469 Istanbul, Turkey;
[email protected] * Correspondence:
[email protected]; Tel.: +90-262-675-3279 Received: 26 February 2019; Accepted: 22 April 2019; Published: 6 May 2019 Abstract: Surface deformations were observed in Bolvadin, located in the province of Afyon (western Turkey) in the last decade which occurred without any destructive earthquakes. In this study, ground deformation of the Bolvadin region is analyzed by means of multi-temporal interferometric synthetic aperture radar (InSAR) technique with Sentinel-1 synthetic aperture radar (SAR) data. Sentinel-1 data acquired in ascending and descending orbits between October 2014 and October 2018 are processed with the Sentinel Application Platform (SNAP) and Stanford Method for Persistent Scatterers (StaMPS) open source software tools. Deformation velocity maps and line-of-sight (LOS) displacement time series are produced and compared with geology, groundwater level and the water surface area of Eber Lake nearby. Deformation velocity maps reveal significant subsidence in most of the town and surrounding regions, which is confirmed by field observations that show severe damage to the settlements and infrastructure of the town. The most severe subsidence is observed to be in the southern part of Bolvadin with rates up to 35 mm/year, which is characterized by the presence of soft alluvial deposits.