Fragility Curves of RC Buildings in Southeastern Turkey: Learning from Seismic Damage Data of The February 2023 Turkey Doublet Earthquakes

Abstract Mw 7.8 and 7.5 strong earthquakes struck the Kahramanmaras province, southeastern Turkey on 6 February 2023. More than 50,000 and 8,400 lives were lost in Turkey and Syria, and approximately 230,000 buildings were destroyed or heavily damaged. 379 and 387 strong-motion stations in Turkey observed the Mw 7.8 and Mw 7.5 strong ground motions, nineteen and one of them recorded the east-west peak ground acceleration (PGA) larger than 500 cm/s², respectively. Referring to the building damage assessment map of 2023 Turkey earthquakes, we calculated the averaged damage ratio of 24 strong-motion stations with a circle of 100m in radius. Site effects in several specific southern Turkey cities may lead to a very irregular distribution of building damage. Based on the reinforced concrete (RC) analysis model of building damage probability created from the building damage data of the 1995 Hyogo-ken Nanbu (Kobe) earthquake, we estimated the building damage probability of these southeast Turkey strong-motion stations. The optimal seismic vulnerability functions of residential RC buildings in southeast Turkey were obtained. The shear strength might be set to 60% of OLD-RC structure or 40% of NEW-RC structure in the Nagato-Kawase model for Kobe earthquake when build the building seismic damage probability model of southeastern Turkey.