Stress status of earthquakes in the immediate vicinity before and after 6 February 2023 Kahramanmaraş earthquakes (Mw7.7 and Mw7.6) in terms of prediction of destructive earthquakes

Abstract

Abstract b value analysis obtained using earthquake catalogues has been associated with stress accumulation for a very long time. In this study, the spatial and temporal distribution of the b value, also known as the frequency magnitude distribution factor, was calculated and examined before and after the February 6, 2023, Kahramanmaraş earthquakes (Mw7.7 and Mw7.6). For this, all earthquakes that occurred between 1900 and the earthquakes of February 6, 2023, and all aftershocks that occurred until September 1, 2023, were used. A circular area with a radius of 300 km, including nearby active faults from the center of the first earthquake to the center of the second earthquake, was divided into grids of equal size. The b value was calculated for each grid using the maximum likelihood method. Very low b values were detected in the area where the first earthquake occurred, and it was observed that the b value decreased relatively in the area where the second earthquake occurred. From the change in b value over time, it was determined that the b value has decreased significantly in recent years. This situation is associated with stress accumulation in the area where both earthquakes occurred, especially the low b values of the region where the first earthquake occurred. The fact that b values obtained using aftershocks are still low is evidence that the tension in the region has not been completely relieved and aftershocks will continue for a long time. At the same time, as a result of this study, the low b value was considered as a precursor to major earthquakes.