STRAIN ANALYSIS OF THE KAHRAMANMARAŞ EARTHQUAKES (6 FEBRUARY 2023) USING CORS-TR DATA

Türkiye is a seismically active region, which frequently leads to the occurrence of earthquakes across the country. The high seismic activity and frequent earthquakes in Turkey have attracted the attention of many researchers. Using Global Navigation Satellite Systems (GNSS), one of the fundamental geodetic measurement techniques, it is possible to compute earthquake-induced displacements and perform strain analyses. This study aims to determine the strains caused by the earthquakes that occurred on February 6, 2023, in Kahramanmaraş, using data from the Continuously Operating Reference Stations-Türkiye (CORS-TR). For this purpose, a total of 31 days of 24-hour RINEX data, including pre-earthquake, post-earthquake, and earthquake-day, from 21 CORS-TR stations were analyzed. These datasets were processed using GAMIT/GLOBK, AUSPOS, and Trimble-RTX software, and two-dimensional strain analyses were conducted based on the derived coordinates. The study area was divided into 28 triangular elements, with the CORS-TR stations serving as vertices, and strain analyses were performed for each triangle. The results reveal that the largest strains occurred in the EKZ1-MAR1-ANTE and EKZ1-ANTE-MLY1 triangles, due to the proximity of EKZ1, MAR1, ANTE, and MLY1 stations to the epicentres. Moreover, considering the coordinate displacements, the largest shifts were observed at EKZ1, MLY1, MAR1, ANTE, and TUF1 stations, respectively. Based on this observation, each station was subsequently selected as a reference point, and strain parameters were computed relative to directions originating from these reference points. The parameters obtained from different software packages were consistent with each other, similar to the triangular division method.