Soil liquefaction and subsidence disaster in İskenderun related to the 6 February 2023 Pazarcık (Mw: 7.7) and 20 February Defne (Mw: 6.4) earthquakes, Türkiye

Abstract

: The Mw 7.7 Pazarcık earthquake on February 06, 2023, struck southern Türkiye, causing typical liquefaction along the shores of İskenderun Bay. This liquefaction was characterized by lateral spreading, subsidence, and flooding. Subsidence-triggered sand ejecta, water flows, and opening cracks were identified in areas spanning approximately 2 km in length and 300 m in width. Based on coastal references such as lighthouses or harbor platforms, settlements of 0.8 m and lateral spreading of 0.4% were recorded along the coastal zone following the Pazarcık earthquake. According to camera recordings, liquefaction-related water and silty sand outflows occurred 29 min after the earthquake. The largest water outlet observed had dimensions of 2 m in length, 1 m in width, and 0.5 m in depth. Images captured at the moment of liquefaction show water gushing for 2 m.