Site-specific probabilistic seismic hazard analysis in Nuweiba, Gulf of Aqaba, Egypt: Combining area source model and active faults

• Published in: Journal of African earth sciences (1994) 2024-07, Vol.215, p.105290, Article 105290
• Main Authors: Badreldin, Hazem, ElHadidy, Mahmoud, Abu El-Ata, Ahmed, Lala, Amir M., Abd el-aal, Abd el-aziz Khairy
• Format: Article
• Language: English
• Subjects: Active faults; Gulf of Aqaba; Logic tree; PSHA; Site-specific seismic hazard; Vs30
• ISSN: 1464-343X; 1879-1956
• DOI: 10.1016/j.jafrearsci.2024.105290

Gulf of Aqaba in Eastern Egypt is characterized by significant seismic activity and high deformation rate, making it a major source of destructive earthquakes in the region. While previous studies have produced probabilistic seismic hazard analysis (PSHA) maps for the region, they have not adequately accounted for active faults or site response in their calculations. This study introduces a newly developed seismic source model for the Gulf of Aqaba, considering area source, active fault source, and a combination of both models to improve seismic hazard assessment for the region. The study incorporates the previously measured average shear-wave velocity for the upper 30 m (Vs30), fundamental frequency (F0), and amplification factor (A0) at some selected sites in Nuweiba city. Accordingly, site-specific PSHA is carried out for the bedrock condition (Vs30 = 800 m/s, according to the Egyptian Building Code) and for the surface of soft sediments using F0, A0, and Vs30. Uncertainties in slip rate, maximum magnitude, and recurrence model are accounted during PSHA computation. Ground motion parameters such as peak ground acceleration (PGA) and spectral acceleration (SA) for various probabilities of exceedance in 50-year lifetime are calculated for both rock site conditions and soft sediments. The maximum calculated PGA and SA are 0.65 g and 1.25 g, respectively, for a 10% probability of exceedance over 50 years at bedrock conditions. •New seismic source model for Gulf of Aqaba is developed using active faults database.•PSHA is conducted at bedrock site condition and surface of soft sediment using F0, A0, and Vs30.•Uncertainty in slip rate, maximum magnitude, and seismicity parameters is considered.•PGA and SA periods for various probabilities of exceedance are computed.