Geotechnical Investigations of the Ground Surface Deformations Associated with Local Soil Conditions During the February 6th Kahramanmaraş Earthquakes

During the devastating Kahramanmaraş earthquake doublets, numerous ground surface damages, including cracks, ruptures, ground separations, and settlements, were observed. While some incidents are associated with liquefaction, others were due to strong ground shaking. Such cracks caused severe upper structural damage, which was observed along roads and highways around reinforced concrete (RC) structures, and in infrastructural systems. It is of special interest to investigate such surface ground damages, as they not only indicate a colossal event but also adversely affect many industrial areas, resulting in significant economic losses. Such surface damages are observed to be threefold. One consists of observed liquefaction-induced damage on the ground surface, another is due to propagating fault-induced rupture causing soil mass movements in landslides, and the last is because of fissures and tensile cracks associated with lateral movement. Damage is also observed on roads, ports, factory buildings, and RC structures. Each case requires special attention, bearing forensic investigation. Thus, this paper focuses solely on the geological and geotechnical aspects of such surface damage. Numerous site investigations have been completed, along with seismic surface measurements aided by laboratory and field tests. As a result, while liquefaction plays a vital role in causing some of the related surface ground damages, intense ground shaking with large surface accelerations also plays a key role in the observed surface deformations.