Seismogenic independence of earthquake doublet: Insights from the 2023 Kahramanmaraş, Türkiye earthquake sequence

Abstract

The interplay between large earthquake doublets often involves a triggering mechanism, yet the specifics of their interaction during the seismogenic process remain poorly understood. Here, we examine the seismogenic relationship using the 2023 Kahramanmaraş, Türkiye earthquake doublet. By analyzing repeating earthquakes (REs) prior to the two 2023 events, we estimated the pre-seismic deep slip rates along the East Anatolian Fault (EAF) and assessed fault movement. Utilizing two distinct earthquake relocation techniques, we identified REs and improved the accuracy of their locations. Our findings reveal a higher deep slip rate of approximately 20 mm/year at the Maras triple junction (MTJ) of the EAF, contrasting with previous estimates based on surface fracture observations. The dense clustering of REs at the MTJ suggests that the seismogenic zone of the first event was weakly coupled and may have undergone accelerated creep before the doublet. Conversely, the seismogenic zone of the second event showed minimal seismic activity and a lack of REs. Integrating these results with regional tectonic data, we suggest that the seismogenic environments of the doublet are markedly different, indicating that the seismogenic processes of the two events are largely independent.