Contrasting lithospheric structure beneath the 2023 earthquake doublet in southeastern Türkiye

Large continental earthquakes occur at major crustal fault zones that mark the boundaries of major tectonic plates or blocks. However, the role of lithospheric structures on the nucleation and rupture process of large seismic events remains poorly understood. Here, we integrate newly acquired seismic and magnetotelluric data to delineate the key lithospheric interfaces and resistivity anomalies along the rupture zones of the 2023 Kahramanmaraş earthquake doublet in southeastern Türkiye. Our results reveal contrasting structures beneath the two events. The first earthquake occurred within a high-resistivity domain featuring a sharp and shallow Moho discontinuity and a shallow Lithosphere–asthenosphere boundary (LAB) in the Arabian plate. In contrast, the second event originated near a resistivity boundary coinciding with a wider and deeper Moho, and deeper LAB in the Anatolian block. Both mainshock ruptures and aftershocks occurred in regions with relatively high resistivity compared with surrounding areas. We also identify several lithospheric-scale conductors that are likely indicative of fluid migration pathways. These observations demonstrate how structural heterogeneity controls stress accumulation and fluid distribution and then contribute to large continental earthquake sequences.