High-Resolution Surface Deformation and Slip Distribution Observations for the 2023 Kahramanmaraş, Türkiye, Earthquake Sequence Help Constrain the Rupture Process

ABSTRACT

Splay, or branch, faults are a common geometric feature of earthquake surface ruptures and may provide constraints on the rupture behavior of an earthquake. The 2023 Mw 7.8 Pazarcık and Mw 7.5 Elbistan, Türkiye, earthquakes are examples of ruptures with multiple small splays, and the Pazarcık earthquake nucleated on a splay fault, the Narlı fault, before rupturing bilaterally on the East Anatolian fault (EAF). Here, we present 3-m-resolution surface displacement from subpixel correlation of Planet Dove optical images for the entirety of both ruptures with corresponding surface slip distributions. For a 30-km-long study region spanning the Narlı-EAF intersection, we compare surface slip derived from five data sets with different resolutions (on-the-ground, WorldView, Planet Dove, Sentinel-2, and Sentinel-1) to elucidate complementary information. In addition, we integrate information from the surface expression of faulting with published dynamic rupture simulations and rupture process studies to constrain a rupture evolution for the Pazarcık earthquake that is consistent across data sets. This work highlights the complementary nature of disparate surface slip data sets and the role that high-resolution surface displacement information, including from fault splays, can play in constraining nonunique rupture models and refining understanding of the earthquake rupture process.