Examination of the Relationships between TEC Changes and Space Weather Conditions Before and After the February 6, 2023 Kahramanmaraş Earthquake (Mw= 7.8 and Mw=7.5)

Abstract

Earthquakes are major natural disasters that cause loss of life and property. Predicting earthquakes in advance is highly important. In recent years, GNSS measurements have been used to predict earthquakes, particularly by analysing total electron content (TEC) values obtained from these measurements. However, it is crucial to accurately analyse the TEC changes influenced by space weather conditions and distinguish them from those caused by earthquakes. This study investigated the impact of the Pazarcık-Kahramanmaraş (Mw: 7.8) and Ekinözü-Kahramanmaraş (Mw: 7.5) earthquakes that occurred on February 6, 2023, on TEC changes. To achieve this goal, space weather conditions, such as the Kp, Dst (nT), F10.7 (sfu), P (\(N⁄c{m}^{3}\)), Bx (nT), By (nT), and Bz (nT) indices, were examined for one month before and after the earthquake occurred. Potentially active days were identified. After establishing space weather conditions, their impact on TEC changes was investigated. The results indicated that there was no significant influence of space weather conditions on TEC changes during the selected time frame, suggesting that these changes may be attributed to the earthquake. Additionally, CODE-TEC and ESA-TEC values for the selected time frame were obtained using the coordinates of 15 CORS-Tr stations in the earthquake region. The upper and lower boundary values of the TEC were determined, and days with anomalies were identified. As a result, it was found that there were days with a positive anomaly approximately 15–18 days before the occurrence of possible earthquakes, which could serve as a preparation period. Furthermore, postearthquake anomalies were suggested to potentially be caused by aftershocks.