The complex dynamics of the 2023 Kahramanmaraş, Turkey, <i>M</i><sub>w</sub> 7.8-7.7 earthquake doublet.

Jia, Zhe; Jin, Zeyu; Marchandon, Mathilde; Ulrich, Thomas; Gabriel, Alice-Agnes; Fan, Wenyuan; Shearer, Peter; Zou, Xiaoyu et al. · Science · 2023

basic_science · Level V

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Abstract

The destructive 2023 moment magnitude (<i>M</i><sub>w</sub>) 7.8-7.7 earthquake doublet ruptured multiple segments of the East Anatolian Fault system in Turkey. We integrated multiscale seismic and space-geodetic observations with multifault kinematic inversions and dynamic rupture modeling to unravel the events' complex rupture history and stress-mediated fault interactions. Our analysis reveals three subshear slip episodes during the initial <i>M</i><sub>w</sub> 7.8 earthquake with a delayed rupture initiation to the southwest. The <i>M</i><sub>w</sub> 7.7 event occurred 9 hours later with a larger slip and supershear rupture on its western branch. Mechanically consistent dynamic models accounting for fault interactions can explain the unexpected rupture paths and require a heterogeneous background stress. Our results highlight the importance of combining near- and far-field observations with data-driven and physics-based models for seismic hazard assessment.