Investigation of seismic site effects in the 6 February 2023 Kahramanmaras earthquakes: A case study of Gölbaşı

Many structures were damaged as a result of the Mw: 7.7 earthquake that occurred on February 6, 2023, with the epicenter in the Pazarcık district of Kahramanmaraş province and the Mw: 7.6 earthquake that occurred in the Elbistan district. Some of these damages occurred as a result of liquefaction occurring in weak soil layers. In the field investigations, damages such as settlement and loss of bearing capacity were observed in the structures located in the region where alluvial soil layers are located in Gölbaşı district of Adıyaman province, as a result of liquefaction. In this study, liquefaction potential analyses of the region were performed using analytical and empirical methods in the literature using the data obtained as a result of field tests in the Gölbaşı district. As a result of the analyses, liquefaction potential index(LPI) and liquefaction severity number(LSN) distribution maps for the region were created. Site-specific soil response analyses were conducted to investigate the effects of earthquake waves coming from the bedrock on the accelerations occurring on the surface in areas with different soil profiles and liquefied layers. Equivalent and nonlinear one-dimensional ground response analyses were performed using two different software and the results were compared. It was examined in two different studies, namely general field response analysis and Gölbaşı specific field response analysis. Response spectra were compared with design spectra created according to the regulation. When the spectra were examined, it was seen that ground amplifications occurred in certain periods. In the analyses where liquefied layers were modeled, it was concluded that the liquefied layers damping the accelerations and transmit them to the surface.As a result of this study, a seismic assessment was presented in line with the data obtained for the Gölbaşı district.