Application of NEHRP classification to AVS30 obtained from microtremor array measurement in Muscat, Oman

This study is the first case in the Sultanate of Oman aimed to take advantage of Microtremor Array Exploration for determining shear-wave velocity structure at a site in the Sultan Qaboos University (SQU), Muscat city, Sultanate of Oman. The Spatial Autocorrelation (SPAC) method that uses array observation of Microtremors was performed to determine dispersion curve of surface-wave phase velocity in the frequency range from 2.5 Hz to 9.5 Hz. An inversion technique was applied to convert it to shear wave velocity profile of the examined site. The estimated shear wave velocity at the maximum survey depth (80 m) is bigger than 900 m/s and the average shear wave velocity in the upper 30m (AVS30) is 379 m/s. Then National Earthquake Hazards Reduction Program (NEHRP) approach is applied for site classification. Consequently, the site is classified "C" of NEHRP index (360 m/s <A VS30 <760 m/s) and the ground consists of mostly stiff soil. In conclusion, our results support the idea that SPAC method with NEHRP approach is very useful tool for site classification and then for seismic microzonation studies of Muscat city.