The 2023 Pazarcık (Kahramanmaraş, Türkiye) Earthquake (Mw: 7.7): Implications for surface rupture dynamics along the East Anatolian Fault Zone

Southern Türkiye faced widespread catastrophic destruction by two devastating earthquakes on the same day. As the earthquakes occurred at 04:17 (Mw=7.7, Pazarcık, Kahramanmaraş) and 12:30 (Mw=7.6, Elbistan, Kahramanmaraş) on February 6, 2023, neighboring active fault systems were broken in succession between the Hatay and Malatya Provinces in the region. The first earthquake, one of the largest earthquakes in this region during the last century, caused widespread damage to infrastructure and buildings, and produced large scale seismo-gravitational surface deformation such as landslides, lateral spreading, liquefaction and also extensional cracks. Here, we present the surface rupture geometry and coseismic displacement characteristics of the fault systems, determined with field observations immediately after the February 6, 2023 Pazarcık (Kahramanmaraş, Türkiye) earthquake (Mw=7.7). Preliminary results show that the total rupture length (L max ) is 270±10 km on the Karasu, Pazarcık and Erkenek segments of the East Anatolia Fault Zone. Left-lateral strike-slip faulting is developed with a maximum horizontal displacement (D max ) of 7.30 m and an average displacement (D avg ) of 3.00 m. Although the surface rupture generally exhibits a narrow deformation zone width of 2-5 m, it expands up to 50 m in some sections of the faults. Our implications for rupture dynamics suggest that fracture development started on a secondary fault (Narlı Fault), transferred to the main fault and triggered the breaking of asperities on Pazarcık segment which exhibits a long period accumulation of stress to initiate the major rupturing. Supplementary material: Figures S1 – S12 with details on coseismic displacement are available at: https://doi.org/10.6084/m9.figshare.c.6487245