Earthquake hazard and risk analysis of the Red Sea region

The Red Sea region, including the Gulf of Suez and Gulf of Aqaba, has suffered frequently from strong earthquakes. Although Red Sea seismicity is described as moderate to low, there is a probability of occurrence of damaging earthquakes in the southern Red Sea and Gulf of Aqaba. The main objective of this chapter is to provide utilities with a practical and effective seismic hazard assessment that is appropriate for the seismic risk analysis of the Red Sea region. The approach consists of characterizing the seismic source zones combined with ground motion prediction equations (applicable to the Red Sea region) within the probabilistic seismic hazard analysis (PSHA) framework that can be utilized in the seismic risk analysis. The risk analysis is performed for credible earthquake design of the common building classes of the region. The fundamental results comprise detailed probabilistic hazard analysis and maps of peak ground motions, spectral acceleration for short period (SS = 0.2 second) and long periods (S 1 = 1 second), and Uniform Hazard Spectra (UHS) with probabilities of exceedance in 50 and 100 years at specific return periods including the regional soil classes effects. Fragility curves were performed for the common building classes of the Red Sea region, and the seismic risk analysis is presented in terms of the earthquake design levels and damage ratios for the cities of highest potential hazard in the region. This addresses an important link between the concepts of seismic hazard as viewed by seismologists and seismic risk as viewed by engineers.