Monitoring deformations caused by Pazarcik (Mw=7.7) and Ekinozu (Mw=7.6) earthquakes in Kahramanmaras on 6 February 2023 with GNSS

Abstract

The high-precision determination of point positioning on the Earth's surface relies on the use of GNSS (global navigation satellite systems). The accuracy achievable in determining point positioning with GNSS depends on factors such as the satellite system used, evaluation software, data collection duration, data recording interval, and other influencing factors. The purpose of this study is to investigate the impact of the two major earthquakes that occurred in Kahramanmaras (Pazarcik, Ekinozu) on 6 February 2023, on CORS-TR stations. For this purpose, the daily RINEX data of 22 CORS-Tr stations located near the earthquake zone between 22 January 2023 and 22 February 2023 were evaluated using the GAMIT/GLOBK, with the help of RINEX data from 10 IGS stations. The daily solutions obtained were divided into two sections: pre-/post-earthquake, to reveal the earthquake's impact on the CORS-Tr stations in the region. The rmse of the coordinates for each CORS-Tr stations was calculated for both pre-/post-earthquake periods. Statistical tests were conducted to determine whether the changes in the stations were significant with a 95% confidence interval. The amount and direction of changes in the stations were identified, and changes in the coordinates were investigated using time series. Furthermore, changes in the base vectors were calculated in parts per million (ppm), and the area change in km(2) for the formed triangles was calculated in m(2). The study revealed that the changes ranging from 4.20 cm to 4.67 m and the largest coordinate change occurred at the EKZ1 station. The change in the base vectors ranged from 0.003 ppm to 48.082 ppm, with the largest change occurring between the EKZ1-TUF1 stations. The comparison of changes in the area revealed that the change per km(2) ranged from 0.09 m(2) to 57.88 m(2), and the largest change occurred in the triangle formed by the TUF1-EKZ1-MAR1 stations.