Post-earthquake scientific investigation is considered as one of the pillars supporting earthquake engineering. On the 6th of February, 2023, two deadly strong earthquakes, which magnitudes were M(w)7.8 and M(w)7.5, respectively, shook Southern-Central Turkiye, caused significantly large casualties and tremendous economy loss. Through on-site field survey, liquefaction phenomena and liquefaction-induced damage to buildings were observed. The observations are: (1) the consequences of soil liquefaction included sandboils, lateral spreading, ground subsidence and ground failure caused by loss of bearing capacity; (2) in two liquefied areas, lateral spreading was investigated and the spreading displacement ranged from several centimeters to meters, resulting in damage or demolishing of buildings; (3) in Golbasi town, many 6 to 10-story buildings significantly subsided and tilted due to liquefaction-induced loss of ground bearing capacity. Buildings subsided by tens of centimeters to 2 similar to 3 m, and tilted by several degrees to tens of degrees; (4) ground subsidence of tens of centimeters with respect to adjacent buildings was detected. The liquefaction phenomena were compared with those triggered by the 2008 Wenchuan, China, earthquake which maintained similar in magnitude and focal depth. The findings and lessons learnt will enhance the understanding of liquefaction hazard, challenge the current liquefaction countermeasures, and eventually facilitate to improve liquefaction mitigation techniques.

This study investigates the effects of the February 6, 2023, earthquakes in T & uuml;rkiye, measuring 7.8 and 7.6 magnitudes (Mercalli intensities XI and X). It comprehensively assesses their impact, along with the subsequent Hatay earthquake (Mw 6.4), on various structures, including residential RC buildings, commercial, industrial, and strengthened structures, as well as critical lifeline components such as roads, bridges, power, and telecommunication systems, and areas affected by soil failures. Immediate field observations were conducted to assess changes and gather insights. The findings will contribute to the development of recommendations for future seismic damage prevention and mitigation strategies.