PSI - Issue 78

Fabio Micozzi et al. / Procedia Structural Integrity 78 (2026) 1205–1212

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© 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of XX ANIDIS Conference organizers

Keywords: 2023 Turkey Earthquake, Surface Faulting, Seismic Vulnerability, Fault-Structure Interaction

1. Introduction On February 6, 2023, southeastern Turkey and northern Syria were struck by two devastating earthquakes in close succession. The first event (Mw 7.7) occurred near Pazarc  k, followed approximately nine hours later by a second earthquake (Mw 7.6) with the epicenter in Elbistan, in the districts of Kahramanmara ş . These events activated multiple segments of the East Anatolian Fault Zone, producing more than 500 km of surface rupture with measured horizontal displacements exceeding 10 meters in some locations. The seismic sequence caused catastrophic impacts on the built environment, with thousands of fatalities and widespread damage to residential buildings, lifelines, hospitals, roads, and bridges. Ground motion effects were exacerbated by surface faulting, particularly in regions where structures were built close to or directly above active fault traces. Strike-slip fault displacement caused localized shearing and dislocation that posed a major threat to the structural integrity of infrastructure. In response to the disaster, an international, multidisciplinary reconnaissance mission was carried out from July 4 to 10, 2023. The team consisted of structural engineers, geologists, geotechnical experts, and urban planners from both the University of Camerino and Adana Alparslan Türke ş Science and Technology University. The objective of the mission was to evaluate the correlation between observed structural damage and proximity to fault rupture. A particular emphasis was placed on damage mechanisms affecting structures intersected by or located near surface faulting, in order to draw engineering and planning lessons for seismic design in fault-prone regions. The group explored areas affected by surface faulting in the provinces of Hatay, Kahramanmara ş , Gaziantep, and Ad  yaman. A total of 334 fault rupture records were collected through a combination of classical geological field mapping, UAV based photogrammetry, and GPS-referenced site inspections. The survey included a systematic documentation of structural and infrastructural damage near and across the fault, emphasizing cases of fault-structure interaction. Damage observations were correlated with geologic context, fault displacement characteristics, ground motion levels, foundation conditions, and structural typologies. Many papers and reports already published describe the damages and the faulting of the 2023 Turkish earthquakes, like the aforementioned example. Many of them include examples of structures located near or directly on the surface faulting (e.g., Aydan et al., (2024), Akta ş et al. (2024), Damc  et al. (2025), Demir et al. (2025), Ozkula et al. (2023), Shirato and Odawara (2023), Tobita et al. (2024), Toprak et al. (2025)). Overall, considering all the structures analyzed during the reconnaissance and not only the structures directly on the fault trace, the observed structural damage did not present major surprises. Buildings located in areas that experienced high ground accelerations exhibited significant levels of damage, as expected. However, the structural response generally aligned well with expected vulnerability levels based on building typology, construction quality, and the design codes probably in place at the time of construction. Notably, many modern neighborhoods, including several structures still under construction, demonstrated relatively good structural performance, reflecting the benefits of improved engineering practices and code compliance. On the other hand, infill walls once again proved to be a highly vulnerable component. These non-structural elements, often not detailed or anchored to prevent out-of-plane failure, frequently collapsed. Their failure contributed to substantial non-structural damage, often resulting in the loss of functional use of the building and necessitating demolition and full reconstruction, even in cases where the main load-bearing system remained largely intact. The lack of considering the infill behavior during the design phase always resulted in a concentration of the drift in the lower level and consequently also a concentration of damage and possibly an increment of the probability of collapse for many structures. Fig. 1 collects images of modern neighborhoods where a large amount of buildings experienced very high level of non-structural damages and collapses, ultimately necessitating the demolition of the entire district. Although no direct observation of surface faulting was made across this neighborhood, it lies between the along-strike projection of the fault trace mapped a few hundred meters away, showing approximately 1 m long horizontal displacement. The effect of the infill