EMPIRICAL FRAGILITY ASSESSMENT AFTER THE 6 FEBRUARY 2023 KAHRAMANMARAŞ-GAZİANTEP TÜRKİYE EARTHQUAKE

Orhun Kalyoncu

(Thesis Supervisor: Prof. Dr. Ufuk Hancılar)

ABSTRACT

Post-earthquake field damage assessment play a pivotal role in understanding the causes of extensive structural damage and provide critical data for deriving empirical fragility functions, which are integral to earthquake loss modeling. On February 6, 2023, Southeastern Türkiye was struck by two catastrophic earthquakes with moment magnitudes (Mw) of 7.7 and 7.6, causing widespread devastation across the region.

In the aftermath, the Ministry of Environment, Urbanization, and Climate Change conducted an extensive damage assessment, surveying over 2 million buildings across 11 affected provinces. Using this dataset, this thesis aims at defining and constructing empirical fragility models as region-specific, which refers to building typology-free, considering on the (Mw) 7.7 earthquake, proposing 95\% confidence intervals via Markov Chain Monte Carlo simulation as well. Damage probability matrices for each region are provided in terms of modified mercalli intensity (MMI). Subsequently, these curves undergo detailed statistical analyses to evaluate their reliability and accuracy.

After that, the fragility curves are developed using different land use classes to create urban-zone fragility models. This approach adjusts the curves to better represent urban areas and introduces a method for incorporating land use patterns into fragility assessments. Finally, the fragility functions are compared with existing curves to address regional disparities in construction practices and adherence to seismic codes.