In-situ investigation of site liquefaction and liquefaction-induced damage triggered by the Feb. 6th, 2023, Türkiye earthquakes

Post-earthquake scientific investigation is one of the essentials for earthquake engineering. On the 6th of February, 2023, two deadly earthquakes, which magnitudes were Mw7.8 and Mw7.5, respectively, shook Southern-Central Turkey, caused significantly large casualties and tremendous economy loss. Through in-situ site investigation, the liquefaction phenomena and related damage triggered by the double strong earthquakes are surveyed and preliminarily analyzed. The analytical results indicate: (1) the liquefaction induced by the earthquakes were significant, and distributed in wide area, and caused severe damage to buildings; (2) the consequences of site liquefaction were observed as sand boils, lateral spread, ground subsidence and loss of site bearing capacity, which yielded damage to residence buildings in great extent; (3) the liquefaction-induced lateral spread was observed in two investigation zones, that the distance of lateral spreading ranges from meters to tens of meters, resulting in damage or demolishing of buildings; (4) in an investigation area of Golbasi city tens of buildings were found subsided and tilting due to liquefaction-induced loss of soil bearing capacity. The subsidence of building ranges from tens of centimeters to meters, and the tilting angles vary from several degrees to tens of degrees with a measured maximum angle of 20 degrees in tilt. Through the field survey of liquefaction triggered by the shocks and the analysis of liquefaction-induced consequences, the characteristics of liquefaction and the lessons learned are presented, and the findings are expected to be beneficial for liquefaction hazard mitigation in China.