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Microtremor for Evaluating the Effect of Shallow Sediments on Earthquake Ground Motion at Quseir City, Red Sea, Egypt
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Near Surface Geoscience 2016 - 22nd European Meeting of Environmental and Engineering Geophysics, Sep 2016, Volume 2016, cp-495-00031
Abstract
Recording microtremor data is increasingly used in determining the site effect on earthquake ground motion especially in regions of moderate to low earthquake activity. In this study we used microtremor data to evaluate the effect of shallow sedimentary layers on earthquake ground motion in Quseir city which is located in the Red Sea coast, Egypt. The increasing in urbanization and land use planning, and the constructions of tourist resorts in Quseir city are the motivation of this work. The microtremor data was recorded by single seismic stations and by array of seismic stations at number of sites at Quseir city. The single stations microtremor data was analyzed based on the horizontal-to-vertical (H/V) spectral ratio technique in order to get the fundamental site frequency (f0) and its associated amplitude of ground motion (A0). The raw data of array was analyzed by using the SPatial AutoCorrelation (SPAC) technique to infer the shear-wave velocity structure beneath Quseir city. The results demonstrate that the value of f0 is ranging between 0.56Hz and 2.5Hz. The retrieved shear-wave velocity profile is characterized by significant interfaces at depths 20m, 50m, and 80m corresponding to velocities 170, 240, and 365 m/s respectively. The resulted f0 values were used in the calculation of bedrock depth at the measured sites. The parameters obtained in this study show a good agreement with the geological setting of Quseir city.