Investigation of the effect of Pazarcık, Elbistan (Kahramanmaraş) and Defne (Hatay) earthquakes that occurred in february 2023 on CORS-TR stations

Anatolia has been exposed to many major earthquakes in history due to its location and geological structure. Most recently, the february 2023 earthquakes, which are described as the disaster of the century, occurred, which deeply affected a total of 11 provinces, including Malatya, Elazığ, Adıyaman, Kahramanmaraş, Kilis, Hatay, Gaziantep, Adana, Diyarbakır, Şanlıurfa and Osmaniye. In this thesis, earthquakes occurred at 04:14 and 13:24 (Mw: 7.7, Mw: 7.6) local time on February 6, 2023, centered in Kahramanmaraş (Pazarcık, Elbistan), and at 20:04 local time (Mw: 6.4), centered in Hatay (Defne) earthquakes and their effects on Turkey National Fixed GNSS Network Active (CORS-TR) stations were emphasized. In the first step of the study, in order to reveal which stations were affected by the earthquakes mentioned in the study, processes were made in ITRF14 datum with GAMIT-GLOBK software, using a total of 4 years of GNSS data (rinex) between 2020 and 2023 of all CORS-TR stations, and the affected stations were examined by analyzing the time series. In addition, the coordinates and velocities of these stations in five different combinations; ITRF14, Eurasian Plate fixed, Arabian Plate fixed, Anatolian Plate fixed and Aegean Block fixed were calculated, velocity vectors were drawn with Generic Mapping Tools (GMT), and angular velocities were calculated. The coordinates in the ITRF14 datum, calculated separately for ITRF14, the Eurasian Plate fixed and the Arabian Plate fixed and were also converted into the ITRF96 datum 2005.00 epoch, which is our Turkish National Reference System. In the second steo of the study, the displacements created in the stations by the two earthquakes that occurred on the same day on February 6, 2023 and the earthquake on February 20, 2023 were calculated. Thus, by calculating the total effect of the first earthquake (Kahramanmaraş/Pazarcık, Mw: 7.7), the second earthquake (Kahramanmaraş/Elbistan, Mw: 7.6), the third earthquake (Hatay/Defne, Mw: 6.4), the total effect of the first and second earthquakes, the total effect of the first, second and third earthquakes was calculated. Separate displacement vectors/slips were drawn in GMT for each of them, based on the amount of displacement in the north and east components and the amount of change in the up component and were drawn with GMT.