PSI - Issue 78

Marco Fasan et al. / Procedia Structural Integrity 78 (2026) 831–838

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1. Introduction As part of the Italy –Egypt bilateral research initiative CoReng (“ Conservation of the Religions Complex in Old Cairo through the integration of geosciences and earthquake engineering ”), recognized as a project of Particular Relevance, an integrated methodological framework has been developed to support the seismic assessment and preservation of cultural heritage sites in seismic-prone regions. The CoReng project (Hassan et al., 2025a, 2025b) brings together expertise from structural engineering, seismology, and geotechnical engineering to address the multifaceted challenges associated with safeguarding heritage structures, with a particular focus on Egyptian monuments located in areas of moderate to high seismic hazard. On October 12, 1992, a moderate earthquake near Cairo, Egypt, caused significant devastation, claiming approximately 540 lives, injuring 6,500 people, and damaging or destroying 8,300 buildings (National Earthquake Information System). The seismic event also severely impacted Cairo’s cultural heritage, particularly post -pharaonic monuments. According to the Egyptian Antiquities Organization (EAO), 212 of the city’s 560 Islamic monuments were affected, along with histori c Coptic churches and Jewish synagogues, as reported by the Egyptian Minister of Culture on November 5, 1992. Sykora et al. (1993) classified earthquake damage into three levels — light, moderate, and severe — incorporating both engineering and preservationist perspectives. Below, we present examples of the three damage levels (light, moderate, and severe), with particular attention to the CoReng’s monuments where these effects were observed.  Light damage patterns refer to the development or enlargement of discrete minor cracks in walls, domes, arches, minarets, sagging floors, and broken parapets. Monuments with this damage level were as Abu Sufein Church.  Although the Coptic Museum is not very old, it was included with the moderately damaged monuments due to its adjacent location to the Hanging Church. Historical records indicate that seismic activity, particularly from the powerful Dahshour earthquake in 1992 and the Aqaba earthquake in 1995, has caused moderate damage to the Ben Ezra Synagogue, located in the historically affected area of Old Cairo.  Severe damage refers to the collapsed dome, large floor depression, bulking walls, and broken minarets. Monuments with this damage level were as El-Moalloqa/Hanging Church. Given the vulnerability of such structures, this study focuses on physics-based ground-motion simulations to assess seismic risk and support mitigation strategies for the Religions Complex (The Mugamma' al Adyan) in Old Cairo a site of immense historical and architectural significance. By integrating advanced seismic modeling, this research aims to enhance preservation efforts and reduce future earthquake-induced damage to this iconic complex. The 1992 earthquake caused varying degrees of damage to the Religions Complex, with well-documented structural impacts. A key component of the project is the development of site-specific seismic hazard models that go beyond conventional approaches by incorporating physically-based ground motion simulations. This allows for a more realistic representation of the seismic input, particularly in regions where historical earthquake records are sparse or incomplete. Within this framework, in this paper a preliminary seismic hazard assessment was carried out for the minaret of the Madrasa of Princess Tatar al-Higaziya (Hassan et al., 2023), located near the Religions Complex in Old Cairo an area of high cultural and historical significance. The key point is to include the effect of uncertainties in the hazard analysis, evaluating their impact on computed ground motions, hence also on structural performances. The hazard analysis was conducted using Physics-Based Ground Motion Simulations (PBGMS), which model the full wavefield propagation from the seismic source to the site, accounting for complex rupture processes and local site effects. Crucially, the CoReng approach emphasizes the need to rigorously account for epistemic and aleatory uncertainties in the definition of the seismic source. In this paper, for a target source, variations in the fault geometry and kinematics specifically the depth, dip, strike, rake angles and slip distribution were explicitly incorporated into the source model parametrization, while the location and magnitude retained fixed (Table 1). These variations were propagated to capture a realistic range of possible ground motion scenarios at the minaret site. By integrating this source variability into the PBGMS framework, the CoReng project achieves a refined estimate of the seismic input that reflects both the physical complexity of the seismic source and the uncertainty associated with its characterization. The resulting site-specific response spectra and accelerograms provide a more informed basis for structural assessment and risk mitigation planning. This hazard modeling approach, developed under the CoReng project, demonstrates how advanced seismological tools, when coupled with interdisciplinary collaboration, can