# Probabilistic Seismic Hazard Assessment for United Arab Emirates, Qatar and Bahrain
## 7 Results and Discussion  
The isoacceleration maps (Figure 6) highlight the hazard in the northeastern edge of the UAE (the emirates of Ras Al-Khaimah, Umm Al-Quwain, Fujaira, Ajman, Sharjah, and Dubai), as the area that has a relatively higher seismic hazard values than the rest of the studied region (the emirates of Al-Ain and Abu Dhabi, as well as the cities of Doha and Manama) in the context of a low seismic hazard region. The depicted hazard maps show the same contour line pattern, as they have a decreasing value towards the southwest, which is greatly expected; the far the distance from the most active seismic sources, the lower seismic hazard. For a 10% probability of exceedance in 50 years, the northeastern region has seismic hazard values up to 0.13, 0.30, and 0.07 g for the mean PGA, SA (0.2 s), and SA (1.0 s), respectively. In this area, the emirates of Ras Al-Khaimah, Fujaira, Umm Al-Quwain, and Ajman share approximately the same PGA value (0.13 g for the first two emirates, and 0.12 g and 0.11 g, for the third and fourth ones, respectively) for a return period of 475 years (Table 5). In addition, the SA (0.2 s) values are equal to 0.30 g, 0.28 g, 0.29 g, and 0.26 g for these four emirates, respectively, for the same return period. The cities of Manama and Doha and the emirate of Abu Dhabi are exhibiting the lower PGA (0.06 g, 0.06 g, and 0.05 g, respectively), and SA (0.2 s) values (0.14 g, 0.13 g and 0.12 g, respectively), for the same return period. Finally, the emirates of Sharjah, Dubai and Al-Ain are characterized by in-between PGA (0.10 g, 0.09 g, and 0.07 g, respectively), and SA (0.2 s) values (0.25 g, 0.22 g, and 0.15 g, respectively), for the same return period. Additional seismic hazard values (for 475 and 975 years as return period, and for the considered site conditions) are tabulated for the selected major emirates and cities in Table 5. It depicts the obtained PGA, the maximum spectral acceleration (SA\({}_{\text{max}}\)) and its corresponding natural period (T\({}_{\text{max}}\)), SA (0.2 s), and SA (1.0 s) values for the selected sites. Those obtained seismic hazard values will provide a solid basis for the subsequent studies for site effects, as well as the estimation of the fundamental frequency and amplification factors for different soil profiles at any particular location. Another interesting output results from this assessment are the UHS. In Figure 8, the UHS for a 475 years return period, in comparison with the available seismic design regulations, as well as a proposed design spectrum based on [PERSON] (2016) criterion, are plotted. For each given spectrum, a number of 15 spectral ordinates have been computed in detail during the analysis. They are 0.0 (PGA), 0.04, 0.10, 0.15, 0.20, 0.25, 0.30, 0.40, 0.50, 0.70, 1.0, 1.5, 2.0, 3.0, and 4.0 s. From the displayed UHS in Figure 8, the greatest obtained seismic hazard values (SA\({}_{\text{max}}\)) for a 475-year return period were obtained for the emirates of Ras Al-Khaimah, Umm Al-Quwain, Fujaira, Ajman, and Sharjah (0.31 g, 0.31 g, 0.30 g, 0.27 g, and 0.25 g, respectively), while the lowest ones were obtained for the emirate of Abu Dhabi (0.12 g). In addition, as can be observed in Figure 8 and Table 5, the corresponding natural periods (T\({}_{\text{max}}\)) for the SA\({}_{\text{max}}\) were observed at natural periods of 0.15-0.20 s (usually, they correspond to buildings of three- to four-stories). There are clear differences between the obtained UHS in the current assessment and those elastic response spectra considered as design spectra in the regulations by the governmental agencies in each country. Relatively higher seismic hazard values for those cities (Dubai and Doha; see Figure 8) than those included in the available regulations that are officially enforced by these municipalities have been obtained.