Geotechnical Reconnaissance Observations for Marine Structures after the February 2023 Türkiye Earthquakes

In February 2023, various waterfront structures along the Gulf of Iskenderun coastline experienced ground motions from a magnitude 7.8 (Pazarcık) earthquake, a magnitude 7.6 (Elbistan) earthquake, and subsequent aftershocks with magnitudes ranging from 4.0 to 6.6. To assess the general performance, ASCE/COPRI deployed a reconnaissance team in May 2023 to observe the aftermath. The team focused on observing and documenting the impacts on port systems and harbor structures, specifically structural integrity and operational functionality. This paper is the first of a three-paper series presenting the observations and findings from the field reconnaissance. The focus of the paper is regional seismicity, ground motions, and geotechnical observations. Ground motions recorded during the two main events and two strongest aftershocks were compiled to make comparisons with the 72-, 475- and 2,475-year return period earthquakes used in design per Türkiye’s 2008 Port Regulations. The findings from the evaluation of the ground motions are presented in this paper. In addition, the effects of liquefaction and settlement on coastal structures, specifically reclaimed lands and breakwaters, are documented in this paper.