Determination of block movements for Izmir and uts surroundings using CORS-TR stations data

GNSS (Global Navigation Satellite System) positioning plays a critical role in modern geodesy, navigation, cartography, and numerous scientific research areas. High-accuracy engineering applications, continuous monitoring of tectonic plate movements, and seismic activities provide high temporal resolution data, enabling the observation of crustal changes and detailed information about dynamic geological events. This monitoring contributes significantly to understanding stress accumulation on fault lines, deformation amounts, and to the prediction of earthquakes and the development of disaster management strategies. In Turkiye and surrounding regions, tectonic movements cause time-dependent changes in point coordinates due to deformation and seismicity. These movements are precisely captured using continuously operating stations. The analysis of GNSS data is crucial for tracking these movements. Scientific software for GNSS data analysis provides the desired accuracy levels. To study block movements in and around Izmir, a campaign was planned utilizing TUSAGA-Aktif (CORS-Tr) stations (AYD1-AYD2, AYVL, CESM, DIDI, IZMI, KIKA, SALH). Measurements from 2009 to 2023, with a data frequency of 30 seconds over 24-hour sessions, were used. The GNSS observation data were processed using the academic processing software GAMIT/GLOBK, and the results were combined to obtain long-term time series. Velocity values in the ITRF20 datum were obtained. To examine block movements, displacement values for TUSAGA-Aktif stations were calculated by fixing the Eurasian plate, Arabian plate, Anatolian Block, and Aegean Block with the ITRF2014 datum. As a result, velocity estimates were made for these points, and accuracy values for the North (N), East (E), and Up (U) components were obtained. The results indicated that the values were within expected limits, with accuracies around a few millimeters. The velocity vector values and directions were compared with other studies conducted in the region and were found to be consistent.