The Role of Urban Expansion and Groundwater Conditions in the Spatial Distribution of Building Damage During the 6 February 2023 Kahramanmaraş Earthquakes

The city center of Kahramanmaraş suffered considerable damage as a result of the Mw 7.7 Pazarcık and Mw 7.6 Elbistan earthquakes, which took place on 6 February 2023. The present study examines the impact of urban development, groundwater conditions, and paleo-drainage systems on the pattern of earthquake damage in the Dulkadiroğlu and Onikişubat districts, which make up the urban center of Kahramanmaraş. Geological, hydrogeological, geomorphological, urban development, and building damage data were combined and analyzed using a GIS environment. Kernel Density Estimation (KDE) and spatial overlay analyses were carried out in order to show the spatial concentration of the damage. The results show that severely damaged or collapsed buildings were not distributed at random; rather, they were found in regions featuring largely young geological units, shallow groundwater levels, and former stream channels. In several areas where rapid urban expansion has occurred over the past thirty years, there is a clear spatial relationship between high damage densities and paleo-drainage systems. These findings reveal a spatial relationship between severe building damage and areas characterized by alluvial deposits, reconstructed paleo-drainage corridors, and potentially shallow groundwater conditions. Although the available data do not allow the damage to be directly attributed to site amplification or other geotechnical mechanisms, the observed spatial patterns identify areas where local ground conditions warrant further geotechnical and seismological investigation.