Seismic microzonation of Ubhur district, Jeddah, Saudi Arabia, using H/V spectral ratio

Abstract

Ubhur district is the northern extension of Jeddah. A lot of the new investments and mega structures will be constructed in this area; the highest skyscraper in the Arabian Gulf region will be built in Ubhur. The surface geology of the investigated region is complex, where the sabkha deposits spread everywhere. The subsurface structure of the subsurface soil is complex and includes different soil classes. Microtremor data was acquired at 76 sites located in Ubhur district. The horizontal to vertical spectral ratio technique is used to determine the resonance frequency (f0) and the maximum amplification factor (A0) at the selected sites. This technique is considered as the cheapest and most reliable one for determining the resonance frequency. The acquired data was processed using the Geopsy software where the reliability of the H/V curves and peaks was considered through the data processing and analysis. The results indicate that the predominant resonance frequency of Ubhur district ranges between 0.77 and 5.7 Hz, while the maximum amplification factors range from 2 to 6. It is indicated that the central zone of the Ubhur district is considered suitable for the construction of high-rise facilities compared to other parts of the region, which should be taken into consideration during land use planning.