H. E. Abdelhafiez

Old Cairo, also known as Islamic Cairo, is a UNESCO World Heritage Site representing a rich tapestry of history and culture. Today, among various significant aspects, its cultural heritage necessitates the elaboration of a proactive conservation strategy, which should take advantage of the intrinsic support provided by the efforts documented in the literature that have been made in several scientific fields, disciplines, and directions over the years. Most historic religious monumental buildings in Old Cairo, in particular, not only face the effects of local seismic hazards, which are emphasized by damage by past earthquakes, but also suffer the consequences of several influencing parameters that are unique to the Cairo city context. In this sense, it is known that the structural retrofitting of these monumental buildings requires sound knowledge of technical details and criticalities, based on inspections, numerical simulations, the in-field integration of technologies, and laboratory tests. Many other gaps should also be addressed, and a sound conservation strategy should be elaborated on the basis of a multi-target approach, which could account for the structural engineering perspective but also contextualize the retrofit within the state of the art and the evolution of past events. This is the target of the contemporary “Particular Relevance” bilateral Italy–Egypt “CoReng” project, seeking to define a multidisciplinary strategy for conserving Old Cairo’s cultural heritage and focusing primarily on the case study of the Religions Complex. To this end, a review analysis of major oversights and challenges relating to historic monuments in Old Cairo is presented in this paper. Learning from past accidents and experiences is, in fact, the primary supporting basis for elaborating new operational steps and efficient approaches to mitigating challenges and minimizing the consequences of emergency events. As such, this review contribution specifically focuses on the structural vulnerability of historic monumental buildings in Old Cairo, reporting on past efforts, past strategy proposals, research experiences, and trends.

Old Cairo is a unique site in the world because of its historical, cultural, and religious values. Old Cairo, a UNESCO World Heritage site, represents a rich tapestry of history and culture. Its significance lies in its role as a center of Coptic and Islamic civilizations and its preservation of numerous historical monuments. Today, the conservation of cultural heritage demands a proactive approach that integrates a robust multidisciplinary strategy. This approach must consider the unique characteristics of the heritage itself and the extensive research and efforts devoted to various scientific fields and avenues. As a case study, the focus is on the Religions Complex, the target of the “Particular Relevance” bilateral Italy–Egypt “CoReng” project. The historic Religions Complex in Old Cairo, a UNESCO World Heritage site, faces significant seismic hazards, threatening its irreplaceable Coptic and Islamic heritage. This research contribution focuses on reviewing and assessing aspects of geological and seismic hazards. This assessment serves as a crucial foundation for future vulnerability analyses and the development of effective retrofitting strategies for the Complex’s historic structures. The current work identifies critical vulnerabilities related to sub-surface geology and geotechnical conditions, various deterioration driving forces, rising groundwater levels, and earthquake ground shaking of the complex site to mitigate these risks and ensure the long-term preservation of this invaluable cultural heritage. In addition, attention is given to missing/weak characterization aspects and the proposal of possible future solutions and research developments.

Seismic microzoning is the process of mapping out and comprehending the differences in ground motion due to earthquakes in a certain location. Accurate seismic microzoning is vital for the development and safety of buildings and infrastructure in earthquake-prone locations. In this work, we present the application of microtremors, multichannel analysis of surface and machine learning approaches for seismic microzoning at Benban Solar Park in Aswan, Egypt. The findings of the investigation indicated that the ground at Benban Solar Park was generally stiff, with certain regions having stronger stiffness and damping qualities than others. The data also indicated variances in the ground conditions at various sites inside the solar park, with certain regions having a greater risk of ground motion due to earthquakes. Overall, the combination of microtremors, multichannel analysis, and machine learning has shown to be an excellent strategy for correctly and effectively mapping out the ground conditions at Benban Solar Park and assuring the safety and structural integrity of the solar power plants at the park. Moreover, the results of the research could be used to guide the design and construction of the future solar power plants at the park and to examine the safety and structural integrity of the solar park. Furthermore, the application of these techniques not only ensures the safety and structural integrity of the solar power plants at Benban Solar Park, but also promotes sustainable development by providing valuable information for the design and construction of future solar power plants at the park, in line with the principles of environmentally-conscious and responsible development.

In order to distinguish between shallow earthquakes and quarrying activity, we evaluated 3069 seismic signals from 413 occurrences (112 explosions and 301 shallow earthquakes, depths 5 km), collected by the Aswan seismic sub-network in southern Egypt from 2010 to 2021. The spectral properties and related source parameters (e.g., seismic moment and corner frequency) using the estimated P-wave source spectra for both earthquakes and quarry blasts were investigated. The analysis showed that the P-wave source spectra of shallow earthquakes have higher corner frequencies (8.8–23 Hz) than quarry blasts (1.0–2.6 Hz) within the same magnitude range. The source spectra of quarry blasts exhibited significant misfits with the omega-square model and had steeper falloffs at high frequencies. The selected quarry blasts have a narrow seismic moment range, from 2.03 × 10¹¹to 1.35 × 10¹²Nm. Our results demonstrate that the evaluation of misfit of P-wave spectra from the omega-square source model, based on spectral amplitude characteristics of high- and low-frequency bands, is the most reliable discriminant method in the routine data analysis of the target area.