Seismotectonic implications and strong ground motion modulation of recent significant earthquakes at the North Central Red Sea, Western Saudi Arabia

Abstract

The dynamic rifting of the Red Sea separated the African and Arabian plates, and poses significant earthquake hazard for the eastern and western countries particularly cities situated along the coast line either eastern Egypt or western Saudi Arabia. The northern central, and the southern parts of the Red Sea rifting have experienced various intensities and magnitudes of seismic activities that ranged from small to large earthquakes. The southern tectonic region of the Red Sea has higher earthquake activities than the central and northern ones. The current work aims to investigate the seismotectonic implications of the October 17, 2011 (\({M}_{L}=3.7\)) and the January 16, 2014 (\({M}_{L}=3.8\)) recent earthquakes that located at the Northern Central part of the Red Sea. The strong ground motion hazard parameters resulted from the two mentioned earthquakes are estimated and simulated at the Yanbu city, western Saudi Arabia by integrating the obtained source parameters in the current article with the path attenuation and the site response factors using the stochastic model. The best shearing mechanism obtained using the full waveform inversion technique indicated normal faulting with planes trending in the NNE-SW and NNW-SE directions are controlled the studied region. The integration of the source, site, and path parameters are led to strong ground motion modulation, the modulated parameters are represented by the time series, the peak ground acceleration (PGA), peak ground velocity (PGV) the peak ground displacement (PGD), and the pseud spectral acceleration (PSA). The PGA values of (0.28–0.70 cm/s²) and (0.32–84 cm/s²) are obtained for the October 17, 2011 and the January 16, 2014, respectively. The PSA values of (0.82–2.12 cm/s²) and (0.98–2.49 cm/s²) are obtained for the October 17, 2011 and the January 16, 2014, respectively. The obtained seismotectonic and hazard parameters are essential and crucial for earthquake risks and disasters resulted from the dynamical rifting of the Red Sea that affected the western Saudi Arabia urban development.