LAUSR

Critical infrastructure such as pipelines, tunnels, and bridges are vulnerable to permanent ground displacements. One cause of such permanent ground displacements is the rupture of a fault that propagates up to the ground surface in the case of large-magnitude earthquakes. For the earthquake-resistant design of pipelines, tunnels, and bridges, accurate estimation of such excessive permanent fault displacements is essential. This study provides crucial insights into the earthquake resistant design of critical infrastructure, with implications for the seismic resilience of communities. The 6 February 2023 Pazarcık Türkiye earthquake with moment magnitude 7.8 ruptured three consecutive segments of the East Anatolian fault zone and two segments of the Dead Sea fault zone. This was followed by the 6 February 2023 Elbistan Türkiye earthquake with moment magnitude 7.7. The total observed surface rupture after these events exceeded 567 km, with measured permanent displacements reaching 8.8 m near Ekinözü. Within the scope of this study, probabilistic fault displacement hazard assessment was carried out for the fault sources of the 6 February 2023 double shocks. Computed displacements for different return period levels were critically compared against the observed permanent on-fault displacements. Design on-fault permanent ground displacements were estimated using different methodologies suggested by the Pipeline Systems and Liquid Storage Tanks Earthquake Code of Türkiye (PTECT, 2021) and EN 1998-4:2022. These code-based estimates were compared with observed permanent on-fault displacements and probabilistic fault displacement hazard results.