From rupture to recovery: how fault materials shaped the 2023 Mw7.6 Elbistan Türkiye earthquake surface rupture

How does fault mineralogy influence earthquake rupture behavior? How do ruptures heal in the postseismic period? Addressing these questions improves our understanding of in situ earthquake processes and the controls on local ground shaking. This talk presents new observations from the Mw 7.6 Elbistan earthquake surface rupture - the second large-magnitude event of the devastating 6 February 2023 Kahramanmara?, Türkiye, earthquake sequence. Field observations, mineralogic analyses of unique rupture-interface samples, and quantitative rupture characterization reveal how variations in fault lithology and deformation fabric govern rupture localization and slip behavior. Repeated high-resolution CO? surface flux surveys along the rupture over the two years following the earthquake show that elevated gas flux correlates with the magnitude of surface offset. The rate at which flux declines with time, reflecting a progressive reduction in permeability as fractures close and the shallow fault zone heals, varies along strike and appears linked to the presence or absence of afterslip. Together, these observations link fault mineralogy, rupture mechanics, and postseismic permeability evolution, providing new insight into fault behavior throughout the earthquake cycle.

Speaker: Alexis Ault, Utah State University