Local Site effects for ground motion acceleration and amplification at Bahrah, Saudi Arabia.
The soil conditions variability at site strongly influence ground motions during earthquakes. The disastrous earthquakes have shown that the local site conditions are the essential factors that impact surficial ground motions. In present study, local site effects are evaluated for ground motion acceleration and amplification at Bahrah. The town is situated on quaternary alluvial wadi deposits. The ground motion time series are obtained through Spectral matching technique.. The ground motion time series and shallow Geophysical data are utilized to carry out One-dimensional simulation for equivalent linear seismic response analyses for soil layers. Results of One-dimensional site response analysis are interpolated to generate maps that account for ground motion accelerations and amplifications at top of the soil for selected spectral periods (PGA, 0.1, 0.2 and 2) for 475 years return period. The maximum value of amplification ranges upto 3.46 and acceleration upto 0.86 g. The undulation of bed rock topography and existence of deep soft sediments are reflected considerably on the results of the study area.