In accordance with requirements listed in “Integrated Seismic Risk Study in Community Area (Yanbu Industrial City)”, the site characterization studies have been implemented by ER&E. The main task of this study was the quantification of the relationship between the local geology and the ground motion, in other words the estimation of the resonant frequencies and seismic amplification levels across the entire areas of interest. The shear wave velocity (Vs) of soil layers should be estimated, and the Probabilistic Seismic Hazard Assessment (PSHA) has been performed by ER&E. Thus, to achieve the main target of this proposed
The studies performed by ER&E result in the following :
- Probabilistic Seismic Hazard Analysis
- Uniform Hazard Response Spectra (UHRS), plots and data in digital format as ASCII files, for return periods 475 yrs and 2475 yrs, mean values, rock sites.
- Fractiles (5%, 10%, 50%, 90% and 95%) for selected oscillator natural periods, return period 475 yrs and 2475 yrs, to characterize uncertainty of the UHRS estimations.
- Results of deaggregation of seismic hazard showing predominant earthquakes with specific ranges of magnitudes and distances for selected oscillator natural periods, considering mean values of UHRS and return period 475 yrs and 2475 yrs.
- Site Effect Studies
- The natural periods due to the subsurface sections, or fundamental frequency and the expected amplification factors at the studied area due to the near surface effects.
- The average shear wave velocity down to 30m depth (Vs30) that obtained from seismic techniques of surface wave inversion (using ambient seismic noise).
- Seismic site classification based on the distribution of the obtained Vs30 value and according to the International Building Code (IBC, 2009) and the Saudi Building Code (SBC, 2018).
