Stress-mediated multi-fault rupture dynamics of the 2023 Kahramanmaraş earthquake sequence, Türkiye

The 2023 Kahramanmaraş (M7.8) and Elbistan (M7.6) earthquakes in Türkiye provide a profound case study in multi-fault rupture dynamics. We update a pre-existing Coulomb stress model¹ to analyse the historical and immediatestress conditions that caused this doublet. Our fi ndings indicate the Pazarcık segment of the Kahramanmaraşearthquake source rupture failed under high historical loading (12 bars since 1822) and immediate Coulomb stresstransfer (~2.5 bars) from the initial Narlı rupture. The pattern of stress changes is consistent with the observations ofsuper-shear rupture to the Northeast of the Pazarcık segment and sub-shear rupture speeds to the south-west.Conversely, the Elbistan earthquake was primarily triggered by signifi cant normal stress reduction (unclamping; ~11bars) from the mainshock, which overcame an initially negative stress state, and creating favourable conditions forthe observed super-shear rupture. This sequence underscores the critical role of combined coseismic and long-termstress transfer in driving complex, cascading fault ruptures.