The earth's rotation-dominated seismicity preceding the 2023 MW7.8 Gaziantep, Türkiye, earthquake

Abstract

For earthquakes (M ≥ 4.0) occurring along and around the East Anatolian fault zone and the Dead Sea fault zone within ten years immediately before the MW7.8 Gaziantep earthquake, Türkiye, of February 6, 2023, we explored the correlation between seismicity and the earth's rotation. We statistically evaluated the correlation using the Schuster's test. The results are quantitatively assessed by a p-value. We found a clear downward trend in the p-values from early 2020 to late 2022 in the studied region. We also obtained a spatial distribution of the p-values showing a low p-value area near the northeastern end of the aftershock zone. Although the stress induced by the rotation of the earth is very weak, it could control the earthquake occurrence when the focal medium is loaded to the critical state to release a large earthquake. The decrease in the b-value in the Gutenberg–Richter (G-R) relation is considered in the form of the tectonic stress increase in the crust. We investigated the b-value as a function of time in the study region. We found that the b-value had decreased for about eleven years before the p-value started to decrease, with a relative reduction of 57%. Therefore, the result of the lower p-values obtained in the present study infers that the earthquakes were dominated by the earth's rotation prior to the MW7.8 Türkiye earthquake due to a critical state of the focal region.

Keywords

• Earth's rotation
• MW7.8 Türkiye earthquake
• p-value
• b-value