Multi-Method Analysis of Surface Deformations in Western Anatolia with InSAR and GNSS Data

Abstract

In this study, geodynamic processes in the Western Anatolia Region were analyzed using Interferometric Synthetic Aperture Radar (InSAR) and Global Navigation Satellite Systems (GNSS) data, incorporating wavelet transformation of InSAR time series based on GNSS observations. InSAR data were processed over a six-year period to produce line of sight (LOS) displacement maps. Ascending and descending track data were merged to derive information on both horizontal and vertical displacements. The InSAR-derived displacements were then compared with GNSS station data from the region to assess variations in the east and up components obtained by both techniques. Significant horizontal and vertical displacements were detected. While the Menemen Plain experienced a subsidence of up to 15 centimeters over a six-year period, the island of Samos experienced a rise of 29 centimeters. The performance of InSAR results was evaluated against GNSS data using Root Mean Square Error (RMSE). The RMSE values significantly decreased after applying corrections to the InSAR processing, indicating improved accuracy. For the DEUG station, the RMSE between InSAR and GNSS time series improved to 1.93% in the east component and 5.29% in the vertical component after wavelet-based noise removal. At the IZMI station, the RMSE was reduced to 2.62% (east) and 6.00% (vertical). Finally, at the CES1 station, the RMSE was reduced to 2.71% for the east component and 5.84% for the vertical component, all after correction.