PSI - Issue 78

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

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enhance the resilience of historic cultural assets against future seismic events. This approach, here presented in its preliminary results, serves not only as a case study for the minaret of Princess Tatar al-Higaziya but also as a scalable methodology for the protection of religious heritage structures across other seismically active regions. 2. Methodology In this study, twenty-four preliminary seismic scenarios were computed to model ground shaking at the minaret site, by systematically varying the depth, dip, strike, and rake of the source that generated the 1992 Cairo earthquake (M w 5.8). These scenarios were simulated using Physics-Based Ground Motion Simulations (PBGMS), implemented through a validated web-based application (Vaccari, 2015; Vaccari and Magrin, 2022). The methodology adopts an Extended Source (ES) model to capture rupture complexities such as directivity and fling step, hence, to account for ground motion variability. Ground motions are computed as the tensor product of the earthquake source and the Green’s functions (Panza et al., 2012), incorporating source rupture kinematics, path effects, and local site conditions. The method has been recently benchmarked against past earthquakes and Ground Motion Prediction Equations (GMPEs) (Smiroldo et al., 2025). Synthetic accelerograms were generated in two main phases: fault rupture simulation and wave propagation/accelerogram computation. This process involves modeling the earthquake source, the crustal structure, and site-specific soil conditions. The ES model represents the distributed slip over the fault plane using the PULSYN algorithm (Gusev, 2011). Given the inherent aleatory uncertainty in future fault behavior, a Monte Carlo approach was employed to account for rupture variability. The fault surface was discretized into sub-faults, and the seismic moment was assigned using a non-stationary stochastic process. The model produces source spectra both amplitude and phase that include rupture dynamics and directivity effects. Seismograms were calculated in a laterally homogeneous medium (a semi-infinite space with horizontal layering) up to 10 Hz using the Discrete Wavenumber (DWN) technique (Pavlov, 2009). The adopted crustal model and site conditions, were derived from (Hassan et al., 2017, 2020). For the Dahshour seismogenic source (the source zone of the 1992 earthquake, M w 5.8), the estimated maximum magnitude ( M max ) varies across different studies (e.g. El-Aziz Khairy Abd El-Aal, 2010; Mohamed et al., 2012; Sawires et al., 2016), For this study, which focuses mainly on focal mechanism parameters influence, we decided to adopt a working scenario magnitude equal to 6.5; in fact, this value is also consistent with M design definition (Rugarli et al., 2019; Wen & Wang, 2024) applied to the 1992 earthquake and the associated magnitude uncertainty, which provides a cap that explicitly accounts for uncertainties in magnitude estimation. Source focal mechanism variability (i.e. depth, dip, strike, and rake) was explicitly considered based on available parameters (Abu El-Nader and Hussein, 2018; National Research Institute of Astronomy and Geophysics (NRIAG), 2024). The adopted source scenarios are summarized in Table 1.

Table 1. Main seismic source variables of adopted scenarios

Mw Lon [°]

Lat [°]

Depth [km]

Strike [°]

Dip [°]

Rake [°]

Mw Lon [°]

Lat [°]

Depth [km]

Strike [°]

Dip [°]

Rake [°]

Sce01 6.5 31.1 29.8 20 Sce02 6.5 31.1 29.8 20 Sce03 6.5 31.1 29.8 20 Sce04 6.5 31.1 29.8 20 Sce05 6.5 31.1 29.8 20 Sce06 6.5 31.1 29.8 20 Sce07 6.5 31.1 29.8 20 Sce08 6.5 31.1 29.8 20 Sce09 6.5 31.1 29.8 20 Sce10 6.5 31.1 29.8 20 Sce11 6.5 31.1 29.8 20

285 30 190 285 66 190 285 30 350 285 66 350

Sce13 6.5 31.1 29.8 10 Sce14 6.5 31.1 29.8 10 Sce15 6.5 31.1 29.8 10 Sce16 6.5 31.1 29.8 10 Sce17 6.5 31.1 29.8 10 Sce18 6.5 31.1 29.8 10 Sce19 6.5 31.1 29.8 10 Sce20 6.5 31.1 29.8 10 Sce21 6.5 31.1 29.8 10 Sce22 6.5 31.1 29.8 10 Sce23 6.5 31.1 29.8 10

285 30 190 285 66 190 285 30 350 285 66 350

70 70 70 70

30 190 66 190 30 350 66 350

70 70 70 70

30 190 66 190 30 350 66 350

170 30 190 170 66 190 170 30 350

170 30 190 170 66 190 170 30 350